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"fynnashba@yahoo.com" <fynnashba@yahoo.com>: Jul 30 11:29AM -0700 Please I have to make a transformerless power supply using a capacitor. I have made the circuit and its working well, my problem is how to measure the current when its on load and the no-load current. When I use the normal way of measuring current the meter is not stable at all. Please how do l do it. Also for academic purpose how do I calculate the current drawn by the load (the load is a relay) What are the advantages of using the transformerless PSU(using a capacitor) thanks

Phil Allison <pallison49@gmail.com>: Jul 30 07:06PM -0700 fynn...@yahoo.com wrote:   -------------------------------   > Please I have to make a transformerless power supply using a capacitor. > I have made the circuit and its working well, my problem is how to > measure the current when its on load and the no-load current.   ** Our problem is we cannot see you damn circuit !!   Is there one diode or a bridge ?   Is the rely coil switched on and off or shorted to disable ?       .... Phil

Tim R <timothy42b@aol.com>: Jul 31 06:29AM -0700 Seriously? bringing your class homework here?

"Dave M" <dgminala@mediacombb.net>: Jul 31 09:59AM -0500 A few questions to you first, to get an idea as to what you want to do, and what you've done so far.   Are you trying to make a DC power source or an AC source? Is the load the relay coil or a load that is being switched by the relay? What kind of instrument are you using to measure the current, and how are you hooking it into the circuit? Is the relay a DC or AC relay? DC and AC relays are built differently, so they have different characteristics. If it's a DC relay coil, then just measure the coil resistance, divide that value into the voltage across the coil and you'll know what the current should be. If it's an AC relay coil, then you really need the Mfr's specs to know how much current the relay coil will draw. It's not just the coil's DC resistance that determines the current; also the coil inductance.   Cheers, Dave M

Tim R <timothy42b@aol.com>: Jul 31 05:30AM -0700 Huh. Interesting ideas.   I don't know where the air travels now. It might be worth borrowing a smoke tester and checking.   It would be useful to know which component in an amplifier generates the most heat and therefore convective air flow, and which component is most sensitive to overheating. I'm assuming they are not the same component.

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Robert Roland <fake@ddress.no>: Jul 30 12:04PM +0200 >if you test individually: 0.6v one way only   Unless the output is shorted. -- RoRo

Robert Roland <fake@ddress.no>: Jul 30 12:21PM +0200 >Would you think one of those component testers would be able to >identify the PWM reg, at least with a go/no-go result?   I do not know which component tester you are talking about, but I would be very impressed if it could. -- RoRo

T i m <news@spaced.me.uk>: Jul 30 11:54AM +0100 On Sun, 30 Jul 2017 12:21:53 +0200, Robert Roland <fake@ddress.no> wrote:   >>identify the PWM reg, at least with a go/no-go result?   >I do not know which component tester you are talking about, but I >would be very impressed if it could.   Well, whilst I think they are 'quite clever' I agree that it probably couldn't test the TOP223Y's.   http://www.eetimes.com/author.asp?section_id=30&doc_id=1329331   I bought one (ironically) for measuring the ESR on SMPS caps (Topfield STB) but have used it (mostly successfully) for many other things since. ;-)   On that ... do you think it might be worth testing (or even just replacing) the two main caps in case they are getting weak? I note they have an extra heat shrink 'skin', probably because they are pressed up against the tiny heatsink on the TOP223Y's?   Cheers, T i m

Robert Roland <fake@ddress.no>: Jul 30 05:18PM +0200 >Well, whilst I think they are 'quite clever' I agree that it probably >couldn't test the TOP223Y's.   >http://www.eetimes.com/author.asp?section_id=30&doc_id=1329331   I have one similar. Yes, they are impressively clever for the money. By they do not do ICs, only generic components. The only component that I found will fool it, was a germanium power transistor. The low Vbe, combined with the low DC gain probably threw it off.   >On that ... do you think it might be worth testing (or even just >replacing) the two main caps in case they are getting weak?   Hard to say. There are so many factors that affect the aging of caps. It does not take many seconds to take them out and test them, though.   >I note >they have an extra heat shrink 'skin', probably because they are >pressed up against the tiny heatsink on the TOP223Y's?   Yes, I noticed that, too. Hopefully, the TOP does not get all that hot. -- RoRo

T i m <news@spaced.me.uk>: Jul 30 05:30PM +0100 On Sun, 30 Jul 2017 17:18:11 +0200, Robert Roland <fake@ddress.no> wrote:   >>couldn't test the TOP223Y's.   >>http://www.eetimes.com/author.asp?section_id=30&doc_id=1329331   >I have one similar. Yes, they are impressively clever for the money.   Aren't they. ;-)   >By they do not do ICs, only generic components.   My only thought was that whist the TOP is actually a 'clever' 3 pin device, there may be some basic logic that it could respond to that might make the tester think it was a working FET or Triac or some such? eg. You might be able to use it as a go / no-go test, *if* it detected something positive (however misdirected) in comparison to a good one?   >The only component >that I found will fool it, was a germanium power transistor. The low >Vbe, combined with the low DC gain probably threw it off.   Ok ... and that's not even a 'clever' component at such. eh. ;-) >>replacing) the two main caps in case they are getting weak?   >Hard to say. There are so many factors that affect the aging of caps. >It does not take many seconds to take them out and test them, though.   True, as whatever 'glue' they used to hold stuff down seems to have gone off a bit in any case. Maybe I'll replace the diodes first and if the unit then works, treat it to a fair of quality (low ESR?) caps at that point. >>pressed up against the tiny heatsink on the TOP223Y's?   >Yes, I noticed that, too. Hopefully, the TOP does not get all that >hot.   I doubt it would (for that heatsink) as it's got next to no radiative qualities (being partially masked by the cap) and only a small thermal mass. It might just be there to rest the cap on. ;-)   Cheers, T i m

Jeroni Paul <JERONI.PAUL@terra.es>: Jul 30 06:31AM -0700 Last week I was playing my favourite vintage games in my vintage television when the picture began to slightly shake horizontally with a tendency to shift to the left and back to its correct position quickly. I shut down the set, take the cover off and try tapping some boards, that did not change anything. It got progressively worse, shifting more and more to the left, until it stabilized to its new position:   https://imgur.com/a/nNu7b   Now the picture is stable but misplaced. Depending on the picture content the color is decoded or not and darker horizontal bands appear when bright objects are displayed in the hidden part of the picture. Also when tuning the signal from my DTV decoder the horizontal shift is the same but the vertical hold is very weak, it requires precise fine tuning and even so the picture rolls randomly.   This is a 26" Telefunken PAL Color from around 1980 of unknown model/chassis as the identifier label fell off many years ago however the relevant video/sync circuits are identical to chassis 714: http://www.eserviceinfo.com/downloadsm/62140/Telefunken_Chassis%20714.html   It uses a TBA950 IC horizontal oscillator and phase sync, apparently the most likely culprit. I also have my scope in need of repair, so for now only DVM and ESR meter. I have checked U3 12V supply, all capacitors and resistors in the board with special attention to C531 and R531 composite sync pass through and the video buffer in the CHROMA IA board T201, R200, R201, R202 and R203. Given the picture brightness/color did not change I believe the composite video output on pin 201/4 from CHROMA IA should be fine. That leaves the TBA950 itself or some associated component that escaped my checks. Capacitor C538 is tantalum, checks 15 ohm on ESR meter and 10K on resistance check, that could be effect of the IC.   Any thought before I try to source a replacement TBA950? (I couldn't find any in my pile of junk old boards).

T i m <news@spaced.me.uk>: Jul 30 10:49AM +0100 On Sat, 29 Jul 2017 19:26:36 -0700 (PDT), Tim R <timothy42b@aol.com> wrote:   >I run the headphone jack of the PC we use for internet into a Yamaha AV amplifier and a set of stereo speakers. It's not an audiophile system but it's much better than PC speakers.   >It would be really convenient to stand the amp vertically to save desk space. But it has vents top and bottom, none on the front back or sides.   >Can you run these vertically? or do they need the airflow from the bottom to stay cool enough?   If you consider how it cools itself normally, it probably draws a small amount of air in though the bottom and passes it out the top, plus random air movement of air from the top of the board out though the top grille.   So, depending on where the vents were (all along or just specific locations) you might find it could be made to cool better when on it's edge because you could get a greater 'chimney' affect.   On my home server I blocked all the external holes in the case except the air intake under the front panel and the PSU exhaust. I then created air dams from polycarbonate sheet that ensured all the incoming air went over the 3 hard drives and another over the motherboard that ensured the air then went over the RAM and LSI heatsinks, before being drawn out an over the PSU by the only fan in there (in the PSU).   By sealing the case like that, ensured the air had to move *though* the case, and not just round and round inside it and because of it's height and general openness to airflow, convection would possibly keep it cool even if the fan failed (in fact now the PSU only contains a 120mm slow speed fan as the PSU is an external 'brick').   So, say your amp had vents all the way along the top and the bottom but a main board that covered most of the area of the inside of the case. If you blocked off the middle section of the top and bottom of the case and stood it on it's edge, convection would then cause air to be sucked in at the (new) bottom of the case (on both sides), up inside (behind the blocked off bits) and back out of the top? The remaining open grill at each end only needs to roughly equal the cross sectional area of space that is available inside the case.   In fact that's exactly what I have here with a TP-Link 16 port Gb switch where there are only vent holes at the two ends and back and nothing anywhere else (and no fan etc). I use it on it's end and just added some extra feet to (what is now) the bottom to lift the end off the work surface. It's also sitting beside a PC to I also added bigger (stick-on rubber) feet to the bottom (now the side) so that it ensures an airgap between the switch and the PC so that heat can radiate out of the switch case and then air convect up the gap).   With some cardboard and tape you can experiment with your amp and see if it feels hotter in use. ;-)   Cheers, T i m

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Tim R <timothy42b@aol.com>: Jul 29 07:26PM -0700 I run the headphone jack of the PC we use for internet into a Yamaha AV amplifier and a set of stereo speakers. It's not an audiophile system but it's much better than PC speakers.   It would be really convenient to stand the amp vertically to save desk space. But it has vents top and bottom, none on the front back or sides.   Can you run these vertically? or do they need the airflow from the bottom to stay cool enough?

jurb6006@gmail.com: Jul 29 08:24PM -0700 If you are going to really push the thing, a fan would be a good idea.   I had a Pioneer SA-1270 on the floor u on its side running into 2.3 ohms, and cranked quite often. Without the fan, which was a breeze box type, it would start smelling like an overheated iron. I am surprised it survived.   If you are running into eight ohms you probably don't have to worry.   At the very worst you'll have to get one of those little muffin fans and tape it or whatever to the top, the circulation it induces should be as good as the convection the amp was designed for.   Run it a while and feel it, if it is hot get a fan.

N_Cook <diverse@tcp.co.uk>: Jul 30 09:01AM +0100 On 30/07/2017 03:26, Tim R wrote: > I run the headphone jack of the PC we use for internet into a Yamaha AV amplifier and a set of stereo speakers. It's not an audiophile system but it's much better than PC speakers.   > It would be really convenient to stand the amp vertically to save desk space. But it has vents top and bottom, none on the front back or sides.   > Can you run these vertically? or do they need the airflow from the bottom to stay cool enough?   Could you remove the top cover of the amp , cut a hole in the side that would become the new top face and cover that with a fan grille or similar mesh? A matching lower hole would not be required, assuming there will be airflow into the original air vants

Robert Roland <fake@ddress.no>: Jul 29 08:02PM +0200 >D1,4 test as short cct.   I would take those out and check outside the circuit.   If the short is at the output of the bridge rectifier, and all four diodes are good, you should measure a diode drop (0.6 V or so) across the diodes in both directions. -- RoRo

"Dave M" <dgminala@mediacombb.net>: Jul 29 01:17PM -0500 Replace the shorted recctifiers!!!! As a precaution, replace all 4 of them; they're cheap. Even in circuit, they should not test as a short corcuit.   Cheers, Dave M       T i m wrote:

tabbypurr@gmail.com: Jul 29 11:49AM -0700 On Saturday, 29 July 2017 19:03:01 UTC+1, Robert Roland wrote:   > If the short is at the output of the bridge rectifier, and all four > diodes are good, you should measure a diode drop (0.6 V or so) across > the diodes in both directions.   if you test individually: 0.6v one way only if testing at bridge input: 1.2v both ways   An easy way to find faults is to run the psu via a filament light bulb, then it's easy to probe the [dangerously live] circuit for voltages with due care. Since I don't know if you can do this safely, don't do it.     NT

T i m <news@spaced.me.uk>: Jul 29 08:29PM +0100 On Sat, 29 Jul 2017 13:17:05 -0500, "Dave M" <dgminala@mediacombb.net> wrote:   >Replace the shorted recctifiers!!!! As a precaution, replace all 4 of them; >they're cheap. Even in circuit, they should not test as a short corcuit.   <snip>   Thanks Robert / Dave,   I haven't played much with SMPS (for obvious (safety) reasons) so assumed there might be some strange 'appears short but isn't in use' type thing going on. I should have pulled those diodes before asking here. ;-(   However, I just desoldered one end of both and one appears to be dead short but the other was ok (but I've pulled them all).   Problem is, while I probably have 1,000 IN4004's, I don't have any 1N4007's and I'm guessing we need the 1000V peak reverse / DC blocking voltage (rather than just 400) and 700 over 280V RMS? ;-(   So, I can pick some of those up next week (eBay) or it looks like Maplin have 1N4007S's in stock but are they an acceptable equivalent? (Peak forward surge current, 30 not 50A)?   http://pdf1.alldatasheet.com/datasheet-pdf/view/329384/CHENG-YI/IN4004.html   http://www.mouser.com/ds/2/395/1N4001S%20SERIES_F15-1082941.pdf   Cheers, T i m   p.s. How long is a piece of string question but ... Is it 'likely' that diode just went (the charger is a good few years old now and has been used quite a bit), or is it more likely something further down the line took it out?

T i m <news@spaced.me.uk>: Jul 29 08:38PM +0100 >> diodes are good, you should measure a diode drop (0.6 V or so) across >> the diodes in both directions.   >if you test individually: 0.6v one way only   Yeah, my diode test function was showing around 520mV on the good ones.   >if testing at bridge input: 1.2v both ways   Understood.   >An easy way to find faults is to run the psu via a filament light bulb,   I did remember that earlier and was going to rig up a plug - lamp -socket jig to make it easier. I thought I'd better ask here first. ;-)   >then it's easy to probe the [dangerously live] circuit for voltages with due care.   Understood.   >Since I don't know if you can do this safely, don't do it.   Understood. Whilst I have co-designed and scratch built plenty of mains powered kit (including disco sound-to-light, sequencers and strobes) I prefer not to be playing with live kit unless it's the only way (or the kit is very well mounted and otherwise insulated / protected, not just loose on the bench etc).   Cheers, T i m

"tom" <tmiller11147@verizon.net>: Jul 29 03:54PM -0400 "T i m" <news@spaced.me.uk> wrote in message news:h9npnct8gjd7pmoh3e9m6g7sh8rvm06721@4ax.com... > that diode just went (the charger is a good few years old now and has > been used quite a bit), or is it more likely something further down > the line took it out?   It is likely that the off line switch regulator is also failed. Grab a copy of the TOP223Y datasheet to see the reference design for your supply.   Here is a source for those chips:   http://www.ebay.com/itm/5PCS-TOP223Y-Encapsulation-TO-220-Three-terminal-Off-line-PWM-Switch-/371080857393?hash=item5666248731:g:h~8AAOSwnLdWrEJR

"Dave M" <dgminala@mediacombb.net>: Jul 29 02:59PM -0500 Yes, the 1N4007 recrifiers should be good replacements. Likely to be the only problem in your unit.   As a precaution, you should check the large transistors on the board. They are likely to be high voltage MOSFETs, and should NOT be shorted or low resistance from drain to source or from gate to any other terminal. Best to take them off the board to test, since they're certain to be connected to the low resistance transformer windings, which could lead you astray.   Cheers, Dave M   T i m wrote:

"tom" <tmiller11147@verizon.net>: Jul 29 04:02PM -0400 Dave,   The "large transistors" are TOP223Y off line switching regulator ICs. Google the part number for the datasheet and reference design.   Regards       "Dave M" <dgminala@mediacombb.net> wrote in message news:1KmdnWTYV6-adOHEnZ2dnUU7-THNnZ2d@giganews.com...

T i m <news@spaced.me.uk>: Jul 29 09:14PM +0100 On Sat, 29 Jul 2017 15:54:33 -0400, "tom" <tmiller11147@verizon.net> wrote:   <snip>   >> been used quite a bit), or is it more likely something further down >> the line took it out?   >It is likely that the off line switch regulator is also failed.   There are two in this PSU so could that apply to one or both?   > Grab a copy >of the TOP223Y datasheet to see the reference design for your supply.   I have looked at this:   https://www.digchip.com/datasheets/parts/datasheet/373/TOP223Y-pdf.php   ... and see roughly how it would work but not sure if that means I should be able to test it somehow? FWIW, I have one of the little component testers but I don't know if it will know what that is or even damage it?   >Here is a source for those chips:   >http://www.ebay.com/itm/5PCS-TOP223Y-Encapsulation-TO-220-Three-terminal-Off-line-PWM-Switch-/371080857393?hash=item5666248731:g:h~8AAOSwnLdWrEJR   Thanks for that. However I am in the UK and but get them here also. ;-)   Cheers, T i m

T i m <news@spaced.me.uk>: Jul 29 09:22PM +0100 On Sat, 29 Jul 2017 16:02:34 -0400, "tom" <tmiller11147@verizon.net> wrote:   >Dave,   >The "large transistors" are TOP223Y off line switching regulator ICs. Google >the part number for the datasheet and reference design.   Would you think one of those component testers would be able to identify the PWM reg, at least with a go/no-go result?   From testing around there were no shorts around the devices but that doesn't stop them being OC or just non-functional?   Cheers, T i m

"tom" <tmiller11147@verizon.net>: Jul 29 04:23PM -0400 "T i m" <news@spaced.me.uk> wrote in message news:2nqpnct2pd9g7dna6m64vudnfotf5k1t9h@4ax.com...   > Thanks for that. However I am in the UK and but get them here also. > ;-)   > Cheers, T i m   A quick ohmmeter check across the three pins should not show a short circuit.   If it does so in circuit, you may need to remove the device to check.

"tom" <tmiller11147@verizon.net>: Jul 29 04:32PM -0400 "T i m" <news@spaced.me.uk> wrote in message news:2nqpnct2pd9g7dna6m64vudnfotf5k1t9h@4ax.com...   > Thanks for that. However I am in the UK and but get them here also. > ;-)   > Cheers, T i m   Look at fig 8 in the datasheet for how your unit works. If I read your post right, this charges LiIon batteries, right? So the outputs should be about 4.0 to 4.2 volts. There is some feedback coming from the battery that probably looks at the battery temperature for a safety shutdown.   You could probably reverse engineer the whole schematic (or half of it) to get a better view of what is going on.   BTW, the transformer on the right next to the capacitor is not a transformer. It is a common mode choke for RFI filtering.

T i m <news@spaced.me.uk>: Jul 29 09:57PM +0100 On Sat, 29 Jul 2017 16:32:22 -0400, "tom" <tmiller11147@verizon.net> wrote:   <snip>   >> should be able to test it somehow? FWIW, I have one of the little >> component testers but I don't know if it will know what that is or >> even damage it?   <snip>   >Look at fig 8 in the datasheet for how your unit works.   OK. Again, I get the rough idea but I was more into digital electronics than SMPSU etc.   >If I read your post >right, this charges LiIon batteries, right?   Sorry, no, it's a general purpose multi-cell NiCad / NiMh charger Tom.   http://www.conrad.com/medias/global/ce/2000_2999/2500/2500/2503/250363_RB_00_FB.EPS_1000.jpg http://www.ansmann.de/en/service/downloads/send/6-bedienungsanleitungen-aelterer-produkte/66-5207123-energy-16   <snip>   The PSU board feeds a fairly complex logic / output board (4 PSU outputs to the logic board) and in turn the 16 charger outputs.   >You could probably reverse engineer the whole schematic (or half of it) to >get a better view of what is going on.   Ok.   >BTW, the transformer on the right next to the capacitor is not a >transformer. It is a common mode choke for RFI filtering.   Ah, ok, thanks ... that (now) makes more sense as even with that (choke) in and D1-4 out, I've lost the short I was seeing across the mains input. ;-)   Cheers, T i m

"tom" <tmiller11147@verizon.net>: Jul 29 05:17PM -0400 "T i m" <news@spaced.me.uk> wrote in message news:respncdm39h95fhbhrnaukpaaet7f92nbb@4ax.com... > (choke) in and D1-4 out, I've lost the short I was seeing across the > mains input. ;-)   > Cheers, T i m   Ok, good. That makes more sense for why so many outputs.   Doing any measurements on this device (scope, etc) will require an isolation transformer to look at the primary (line) side. The outputs all appear to be isolated.   Hope it's just the shorted diodes.   Good luck.   Regards

tabbypurr@gmail.com: Jul 29 02:27PM -0700 On Saturday, 29 July 2017 20:59:12 UTC+1, Dave M wrote: > the low resistance transformer windings, which could lead you astray.   > Cheers, > Dave M   I've been led astray by small amounts of capacitance before     NT

T i m <news@spaced.me.uk>: Jul 29 10:38PM +0100 On Sat, 29 Jul 2017 17:17:26 -0400, "tom" <tmiller11147@verizon.net> wrote:   <snip>   >> (choke) in and D1-4 out, I've lost the short I was seeing across the >> mains input. ;-)   >Ok, good. That makes more sense for why so many outputs.   It's quite an expensive unit (I think it cost me ~100 UKP some years ago) so I'd like to get it going if I can.   >Doing any measurements on this device (scope, etc) will require an isolation >transformer to look at the primary (line) side.   Understood.   >The outputs all appear to be >isolated.   Ok.   >Hope it's just the shorted diodes.   Fingers crossed. ;-)   >Good luck.   Thanks for your help and I'll let you know how I get on.   Cheers, T i m

tabbypurr@gmail.com: Jul 29 02:45PM -0700 On Saturday, 29 July 2017 22:38:41 UTC+1, T i m wrote:   > >> Ah, ok, thanks ... that (now) makes more sense as even with that > >> (choke) in and D1-4 out, I've lost the short I was seeing across the > >> mains input. ;-)   you would, 99% of the time     > >Good luck.   > Thanks for your help and I'll let you know how I get on.   > Cheers, T i m   if it's only 1 bad diode try running it without it, on half load or less it should be ok. 2x400v diodes in series should do as replacements temporarily.     NT

T i m <news@spaced.me.uk>: Jul 29 11:17PM +0100 On Sat, 29 Jul 2017 14:45:34 -0700 (PDT), tabbypurr@gmail.com wrote:   <snip>   >if it's only 1 bad diode try running it without it, on half load or less it should be ok.   Now I've got them all out it seems to be two bad diodes but one was reading strange things so maybe died fully as I got it out?   >2x400v diodes in series should do as replacements temporarily.   Ok, I can give that a go tomorrow ... especially as I have so many 1N4004's. ;-)   Cheers, T i m

etpm@whidbey.com: Jul 29 12:10PM -0700 I apologize because have very little info on the lamp but am still seeking guidance. My son has this lamp: Larson Electronics epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED modules and each module is driven by its own driver board. Besides various diodes, capacitors, inductors, and resistors each board has an 8 pin device and a power transistor. There are no other semiconductor devices. Only one of the LED modules works properly. All the others flash for a bit, then stay but don't come up to full brightness, and then shut off after several seconds. Then the sequence repeats. My son figured the LEDs were probably driven with a PWM voltage and so he measured the frequency of the power to the LEDs. The one good LED module is being driven at 150 Hz. The failing modules are being driven at various lower frequencies, depending on which module he tested. My son replaced all the electrolytic caps and this had no effect. The 8 pin device on each board has some sort of opaque coating on it that completely obscures and numbers or letters that may be printed on it. I think the problem with the boards is probably the power transistor. I think the 8 pin device is either a microcontroller or a LED driver IC that is designed to drive a power transistor. The meter my son used to measure the frequency of the pulsed DC powering the LEDs is undoubtably some cheap meter so I don't know how trustworthy it is. From what my son says the lamp is supposed to be some kind of "smart" lamp so that it is more efficient etc. and this is why I think the 8 pin device is a microcontroller or a LED driver. I think the various frequency measurements he is seeing are the result of the power transistors failing. I told him he should order some new ones and try them out, especially since, according to my son, they do have legible numbers on them. Since I'm really busy right now and don't know much about how these things work anyway I'm asking for some advice and opinions. So, is the 8 pin device probably a microcontroller? And are failing power transistors probably the problem? What can my son do to determine what the 8 pin device is? Thanks, Eric

Jeff Liebermann <jeffl@cruzio.com>: Jul 29 01:22PM -0700 >My son has this lamp: Larson Electronics >epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED >modules and each module is driven by its own driver board.   Is the lamp one of these? The numbers are similar, but there are additional suffix letters that you did not provide: <http://www.larsonelectronics.com/p-70368-class-1-division-1-explosion-proof-150-watt-high-bay-led-light-fixture-paint-spray-booth-approved.aspx> <http://www.larsonelectronics.com/p-144814-ceiling-mount-explosion-proof-150w-high-bay-led-light-fixture-17500-lumens-140-beam-spread.aspx>   Only $2,200 each: <https://www.grainger.com/product/LARSON-ELECTRONICS-LLC-Explosion-Proof-Lighting-20LN23>   I don't see six LED modules, although with 12 LED's, I can how 6 modules might work and fit: <https://www.google.com/search?q=Larson+Electronics+epl-hb-150led&tbm=isch> No disassembly photos. Bummer.   Could you double check the model number?   If you only have one out of 6 modules currently functional, my guess(tm) is that you're doing something wrong in the operation of the light. It might be getting too hot, insufficient ventilation, or too much applied AC voltage. Difficult to tell from here. If you repair one or more modules by replacing blown parts with identical parts, I would give it 5 chances out of 6 of blowing up again.   What I do in situations like this is first make a schematic. Identify as many parts as possible. For parts obscured with epoxy, use some type of epoxy softener to ID the part: <https://www.dynaloy.com/products/epoxy> With the one remaining working module, use an oscilloscope to measure waveforms and voltages. Be sure to isolate the light with an AC line isolation transformer to prevent the oscilloscope case from being at AC line potential. Or, use a dual trace scope in differential input mode. After you repair a module, compare voltages and waveforms.     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

micky <NONONOmisc07@bigfoot.com>: Jul 29 03:37PM -0400 In sci.electronics.repair, on Sun, 23 Jul 2017 13:35:47 -0400, bitrex >> news:s6d7ncdecv29j9dsl1d12it82u8e8gb6ce@4ax.com...   >> Is my 2004 original equipment CD player likely to be able to play Mp3 >> cds (in the car I just bought)?   This is a Chrysler Sebring, 2004. I don't know who actually made the radio.   >> Gareth.   >IIRC my 2002 Ford Taurus OEM CD player would play CD-Rs of mp3 files, >but not CD-RWs.   Well, I made up a CD on the PC and tried to play it and I got ERR.   I guess I could have done this in the first place, but I learned things in this thread, so it was worth it.   I finally noticed that some CDs are labeled "audio CD" and I guess that's all mine can play.       I didn't mention my previous car, a 2000 Toyota Solara with an AM/FM/6-CD-changer in one box, that I still own, which used to work, then gave Err 2, then worked again after I took it out and fiddled with it a little, then gave Err 2 again, repeat previous step, and then did nothing at all when I pressed the CD button.   But I'm selling the car and it has I think 3 CDs in it.   This time fiddling did nothing, and trying to disassemble didn't accomplish much, so I ended up taking out as many screws as possible and ripping the pieces out.   By the time I was done, the laser assembly didn't slide well on its track, so maybe that's why it finally stopped working (though earlier it was the changer that was causing trouble.) Or maybe I damaged the track or laser carriage when ripping it out, though I don't think so.   But I got the CDs out and there were *four* of them.   I don't know who made that radio either.

micky <NONONOmisc07@bigfoot.com>: Jul 29 03:37PM -0400 In sci.electronics.repair, on Mon, 24 Jul 2017 15:06:47 +1200, >playing them reliably). Back then some players started being sold as being >CDR compatible but after a while it became taken for granted and the badging >vanished.   So this accounts for my original question.

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T i m <news@spaced.me.uk>: Jul 29 05:27PM +0100 Hi All,   I fired my Ansmann Energy 16, cell battery charger up earlier to charge 4 x D NiMh's and initially it looked like it was behaving normally but when I looked at it again a few minutes later, there were no LEDs illuminated? ;-(   Checked the mains (3A) fuse and it was blown, so I removed the cells, replaced the fuse, tried it again and it blew again.   I took it to bits, blew a bit of dust out of it and running the DMM over it on low Ohms, it seems there is a fairly low resistance across the AC input (~ 2 ohms).   <https://www.dropbox.com/s/r93ghlg58qgcxhv/Ansmann%20PSU%20top.jpg?dl=0>   <https://www.dropbox.com/s/yx4vg5td3mqkiu2/Ansmann%20PSU%20bottom.jpg?dl=0>   I then disconnected the PSU and (carefully) ran it up on the bench and again, the fuse blew instantly (however, I'm not sure if it's ok to run the PSU like that with no load etc)?   I de-soldered one end of both the input filter caps, and the first transformer and the very low resistance went away on the input side (so it wasn't a shorted cap) but was still across the board where the txfmr output was. FWIW, of the 4 bridge rectifier diodes D1-4 in the middle of the board, D2-3 test out ok in cct, D1,4 test as short cct. All the other diodes and caps around that part of the circuit seem to test out ok on the DMM (diode test, cap continuity charge 'beep' upon probe connection) so I was wondering if someone could point me in the right direction re checking it out further etc please?   Given there isn't much else on that board, is it likely it's the first txfmr, one (or both) of the TOP223Y's (PWM switch) and how could I test them if it was please? Or could it be the (PC817) opto-isolators as I assume they would be fairly easy to test out of the board?   Thanks for your help in advance ... ;-)   Cheers, T i m   p.s. I might have got some of the above wrong so please assume that to be the case as I don't want to mislead anyone. ;-(

guijarrosoy <algenta@gmail.com>: Jul 28 12:09PM -0700 Hi colleagues.   Trying to fix this console that is having a few burned resistors.   I am interested in obtaining schematic diagram and service manuals if possible.   Thanks and regards.   guijarrosoy@hotmail.com

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 28 08:30PM +0100 "guijarrosoy" wrote in message news:d696fe99-3536-4e99-b04d-eb28d9bcf261@googlegroups.com...   Hi colleagues.   Trying to fix this console that is having a few burned resistors.   I am interested in obtaining schematic diagram and service manuals if possible.   Thanks and regards.   guijarrosoy@hotmail.com       ************************************************************************       https://elektrotanya.com/tascam_m-208_m-216_sm.pdf/download.html         Gareth.

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 28 07:44PM +0100 "Phil Allison" wrote in message news:cb0e3a2a-7c7b-494b-9e6b-762b0de1796b@googlegroups.com...   Gareth Magennis wrote:   -------------------------------   > ***********************************************************   > Sounds pretty likely, I bought them a long time ago.   ** Look like them ??     http://www.canford.co.uk/Images/ItemImages/large/23-064_01.jpg         ************************************************************       Probably decided at the time I didn't really need the mu-metal casing, but yes, this is the type I got. Don't know what impedance, but got 1:1 versions.   http://uk.farnell.com/oep-oxford-electrical-products/a262a6e/transformer-audio-1-1-1-1/dp/1689033     The 4 Neve donuts went into a couple of isolator boxes at live gigs. Still use one box between the live system and the recording laptop / soundcard.       Gareth.           Gareth

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"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 27 07:30PM +0100 "Phil Allison" wrote in message news:50dde5a8-ded1-43bf-90d7-497a26c63e88@googlegroups.com...   Gareth Magennis wrote:   -------------------------   > My test bench has for many years had a couple of ground isolated Neve 1:1 > transformers between XLR input test sockets and stereo monitors.   ** Are they toroidal, red coloured with black potting in the centre ?   > Why is that?   > I guess that means you could never directly connect a CryBaby to any > transformer balanced mixer input.   ** You need an active DI for that job, preferably with JFET input.   Maybe you could add 48V phantom for it to one of the XLRs with two 6.8kohms.       ...... Phil         ******************************************************************     I always just put it through a guitar amplifier, there is usually one around.     Oh, I checked today and my bench doesn't actually have Neve transformers, I used them for another project and got confused/forgot. They are indeed the orangey coloured toroids with potting in the middle, with a threaded insert for mounting.   The ones I used on my bench are pretty much the ones BSS used in their AR116 DI boxes.       Gareth.

Phil Allison <pallison49@gmail.com>: Jul 27 07:07PM -0700 Gareth Magennis wrote:   ---------------------------- > around.   > Oh, I checked today and my bench doesn't actually have Neve transformers, I > used them for another project and got confused/forgot.     ** So it used to have Neve transformers or never had them ?   You are an expert at ambiguous posting.     > They are indeed the orangey coloured toroids with potting in the middle, > with a threaded insert for mounting.     ** Yes, that is the same kind I have seen recently.     > The ones I used on my bench are pretty much the ones BSS used in their AR116 > DI boxes.   ** Potted in a Mu-metal box ?   Made by OEP and sold by Farnell ?       ..... Phil

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 28 09:23AM +0100 "Phil Allison" wrote in message news:70ca723d-a83b-423d-9935-496d9ac1a3fa@googlegroups.com...   Gareth Magennis wrote:   ----------------------------   > Oh, I checked today and my bench doesn't actually have Neve transformers, > I > used them for another project and got confused/forgot.     ** So it used to have Neve transformers or never had them ?   You are an expert at ambiguous posting.     > They are indeed the orangey coloured toroids with potting in the middle, > with a threaded insert for mounting.     ** Yes, that is the same kind I have seen recently.     > The ones I used on my bench are pretty much the ones BSS used in their > AR116 > DI boxes.   ** Potted in a Mu-metal box ?   Made by OEP and sold by Farnell ?       ..... Phil     ***********************************************************     Sounds pretty likely, I bought them a long time ago.       Gareth.

Phil Allison <pallison49@gmail.com>: Jul 28 05:22AM -0700 Gareth Magennis wrote:   -------------------------------   > ***********************************************************   > Sounds pretty likely, I bought them a long time ago.   ** Look like them ??     http://www.canford.co.uk/Images/ItemImages/large/23-064_01.jpg           .... Phil

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Mad Roger <rogermadd@yahoo.com>: Jul 27 12:05AM On Tue, 25 Jul 2017 15:01:45 -0000 (UTC), Mad Roger wrote:   > setup, where the current set of connections includes a few things that we > can discount, such as an autoupdate of some sort, and speedials and some > search engine updates.   Just for the record, here are the startup calls Opera makes to the search engines, even with everything possible in the settings turned off.   These are in order, with, I think, all but the last two not being important, I don't think, for our purpose, and hence can be filtered out.   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 2 200 HTTP www.google.com /favicon.ico 1,494 public, max-age=691200; Expires: Tue, 01 Aug 2017 08:13:18 GMT image/x-icon opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 3 200 HTTP Tunnel to duckduckgo.com:443 0 opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 4 200 HTTP www.bing.com /s/a/bing_p.ico 300 public, max-age=15552000 image/x-icon opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 5 200 HTTP Tunnel to www.amazon.com:443 0 opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 6 200 HTTP Tunnel to www.wikipedia.org:443 0 opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 7 200 HTTP Tunnel to search.yahoo.com:443 0 opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 8 200 HTTP www.ecb.europa.eu /stats/eurofxref/eurofxref-daily.xml 1,624 text/xml opera:2616   # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 9 200 HTTP Tunnel to autoupdate.geo.opera.com:443 0 opera:2616   I think of the nine connections that happen at startup, only #8 and #9 seem significant for our purpose.

"pfjw@aol.com" <pfjw@aol.com>: Jul 27 04:03AM -0700 Please don't feed the troll.

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 26 07:44PM +0100 My test bench has for many years had a couple of ground isolated Neve 1:1 transformers between XLR input test sockets and stereo monitors.   Which has never been a problem, but has ALWAYS been a problem connecting any CryBaby Wah Wah pedal.   If you do, the CryBaby resonates at full volume, behaving much like turning a VCF resonance control to full, so it self oscillates. Why is that?   I guess that means you could never directly connect a CryBaby to any transformer balanced mixer input.         Circuit here:     http://www.electrosmash.com/crybaby-gcb-95       Gareth.

"pfjw@aol.com" <pfjw@aol.com>: Jul 26 12:32PM -0700 Just for giggles, have you tried reversing the plug polarity?   Peter Wieck Melrose Park, PA

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 26 08:50PM +0100 wrote in message news:e3c0123d-c6f9-4d53-ae57-140a34499745@googlegroups.com...   Just for giggles, have you tried reversing the plug polarity?   Peter Wieck Melrose Park, PA   ******************************************************************     No,I thought as it is transformer and ground isolated it shouldn't matter.     Gareth.

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 26 08:53PM +0100 "Gareth Magennis" wrote in message news:Co6eB.357659$_F5.107046@fx40.am4...       wrote in message news:e3c0123d-c6f9-4d53-ae57-140a34499745@googlegroups.com...   Just for giggles, have you tried reversing the plug polarity?   Peter Wieck Melrose Park, PA   ******************************************************************     No,I thought as it is transformer and ground isolated it shouldn't matter.     Gareth.         **************************************************************     The output goes into an inductor, the CryBaby doesn't seem to like it.       Gareth.

"pfjw@aol.com" <pfjw@aol.com>: Jul 26 01:16PM -0700 On Wednesday, July 26, 2017 at 3:51:02 PM UTC-4, Gareth Magennis wrote:     > No,I thought as it is transformer and ground isolated it shouldn't matter.   > Gareth.   If you have the typical "Hot-Neutral" configuration, it does - well - better stated, it can. It does not matter only with hot-hot configurations such as US 240V single-phase connections. Try reversing, and please let us know.   Peter Wieck Melrose Park, PA

"Gareth Magennis" <soundserviceleeds@outlook.com>: Jul 26 10:33PM +0100 wrote in message news:96f2aad0-4bc3-4cee-b9d8-081d277f49bb@googlegroups.com...   On Wednesday, July 26, 2017 at 3:51:02 PM UTC-4, Gareth Magennis wrote:     > No,I thought as it is transformer and ground isolated it shouldn't matter.   > Gareth.   If you have the typical "Hot-Neutral" configuration, it does - well - better stated, it can. It does not matter only with hot-hot configurations such as US 240V single-phase connections. Try reversing, and please let us know.   Peter Wieck Melrose Park, PA       ************************************************************     Hi Peter, I think you have the wrong end of the stick.     This is a guitar effects pedal, a "Wah Wah". It is a resonant circuit that emphasises mid frequencies to produce vowel like sounds when played with a guitar.     The "problem" I have always had is that you cannot connect this to a transformer based pre-amp, as it would seem the inductive load affects the circuitry in a way that seems to make the resonant circuit resonate like crazy. This unit is intended to plug into a guitar amplifier, not a transformer based test bed, where it misbehaves.       Gareth.

Phil Allison <pallison49@gmail.com>: Jul 26 04:39PM -0700 Gareth Magennis wrote:   -------------------------   > My test bench has for many years had a couple of ground isolated Neve 1:1 > transformers between XLR input test sockets and stereo monitors.   ** Are they toroidal, red coloured with black potting in the centre ?   > Why is that?   > I guess that means you could never directly connect a CryBaby to any > transformer balanced mixer input.   ** You need an active DI for that job, preferably with JFET input.   Maybe you could add 48V phantom for it to one of the XLRs with two 6.8kohms.       ...... Phil ..... Phil

"pfjw@aol.com" <pfjw@aol.com>: Jul 27 04:03AM -0700 Gareth:   I know what it is - I have repaired a number similar devices for my neighbor. I suggest what I suggest due to (limited) direct experience with such devices.   If you try this suggestion and it works, good. If not, no loss.   Next thing to look for would be cold-solders or poor connections - most of what I fixed for my neighbor.   Peter Wieck Melrose Park, PA

Mark Zacharias <mark_zacharias@sbcglobal.net>: Jul 26 12:41PM -0700 > Hi, may I ask for some advice? I have an Onkyo 5009 AV Reciever with the very common problem of overheating HDMI board. You can see it just under the grill for cooling in the case. I have an infrared heat sensitive camera and discovered there are several small ic's that get very hot very quickly- i.e. 70-80c. The ICs are very small, 10mmx10mm up to 10mmx16mm and thereabouts but there is space of about an inch above so room for a heat sink maybe? What would you chose to do? Fit heat sinks to those chips(if there are any small enough) or fit fans directly above the board? I'd really welcome your advice.   > Steve   It's the larger BGA chips that suffer from the heat. Recent vintage Onkyo's are notorious for this.

Arfa Daily <arfa.daily@ntlworld.com>: Jul 27 01:39AM +0100 On 26/07/2017 20:41, Mark Zacharias wrote: >> Hi, may I ask for some advice? I have an Onkyo 5009 AV Reciever with the very common problem of overheating HDMI board. You can see it just under the grill for cooling in the case. I have an infrared heat sensitive camera and discovered there are several small ic's that get very hot very quickly- i.e. 70-80c. The ICs are very small, 10mmx10mm up to 10mmx16mm and thereabouts but there is space of about an inch above so room for a heat sink maybe? What would you chose to do? Fit heat sinks to those chips(if there are any small enough) or fit fans directly above the board? I'd really welcome your advice.   >> Steve   > It's the larger BGA chips that suffer from the heat. Recent vintage Onkyo's are notorious for this.   As Mark says ...   Over here in the UK, Onkyo have a free repair service when this board fails due to chips unsoldering themselves. You enter the unit's serial number into a website, and it immediately tells you if it qualifies for free repair. If it does, you fill in address details, and they arrange to collect it and return it fixed, usually within a week.     Arfa

lmmcams@gmail.com: Jul 27 12:58AM -0700 I have sent it for repair once free of charge, but don't want to have to do it again, and if by keeping it cooler I can prevent it, I'd like to go that route. The dts chips that causes the no sound fault in these machines gets Nearly 80c but not as hot as the big chip to its left, I think this is referred to as the Bits Chip. I have plotted all the hot chips sizes and ordered a pile of small heat sinks and a couple of 6" PC fans to fit on the top case to blow air over the board silently. Hopefully, I won't have to get it fixed another time with these mods. I will post a you tube video shortly of the thermal imaging of this board.   Steve

lmmcams@gmail.com: Jul 27 01:48AM -0700 Here's a video of before any mods and after only being on for five mins with no the receiver not doing anything other than being on- https://youtu.be/C6QfmmJzWks

Arfa Daily <arfa.daily@ntlworld.com>: Jul 27 01:26AM +0100 On 22/07/2017 15:54, John Robertson wrote:   > https://www.wonkeedonkeetools.co.uk/circlip-pliers/what-is-a-circlip/   > John :-#)#   Interesting. The design in question is the one they call grip rings,and is the fourth picture up from the bottom. They say that these do not normally fit in a groove, but the ones on my colleague's fan motors do. I spoke to him again today. He has actually ordered a bunch of new clips of the right size, so is now not too bothered about the originals breaking or flying, but has ordered some new pliers that he thinks will do them anyway. Just in case anyone thinks that pulling a small fan apart is not worth the aggro, it turns out that these are fans used on the bed of a printing machine, and are carefully speed controlled by external circuitry driven from a tacho generator in the fan. The purpose is apparently to 'float' the paper as it passes through the machine. They are a custom designed fan from one of the major fan manufacturers, and are over £100 each. There are four to a unit, and many units per machine. So far, all of the ones that he has pulled apart and repaired have had bad joints on the Hall IC in the tacho generator, and have worked perfectly after resoldering, cleaning out, and reassembling. The fans have high quality roller bearings, none of which have shown any signs of wear so far.   Arfa

Arfa Daily <arfa.daily@ntlworld.com>: Jul 27 01:30AM +0100 On 22/07/2017 16:15, Ralph Mowery wrote:   > They look similar and seem to do about the same function, but there are > no holes near the ends.   > http://www.ebay.com/bhp/e-clip-tool   No. Definitely not E-rings. These are a type of 'conventional' circlip, but with a slot in each arm to locate the removal tool pins, rather than holes. Thanks for your input anyway. As ever, all comments / suggestions appreciated.   Arfa

N_Cook <diverse@tcp.co.uk>: Jul 27 09:08AM +0100 On 27/07/2017 01:26, Arfa Daily wrote: > fans have high quality roller bearings, none of which have shown any > signs of wear so far.   > Arfa   Exactly those "grip rings" for jewellers screwdrivers. Find one that just fails to seat in the gap and twist, so it sits neatly between the small Cs, and lift off/replace with ring still on the blade. May need a bit of shim, to lever over the point of a C. To avoid flying rings, a piece of cotton tied to one of the Cs and anchored somewhere at the other end

tabbypurr@gmail.com: Jul 26 03:40PM -0700 On Wednesday, 26 July 2017 17:11:48 UTC+1, Jeff Liebermann wrote: > additives found in modern gasoline is considered most hazardous, but I > suggest you find something a little less dangerous. Please remember > that you have only one life to give for this repair project.   If I knew where I had some in the shed I'd use it, but certainly not in the house.   > Have you tried penetrating oil (Kroil) to break things loose? My > guess(tm) is you're dealing with well hidden rust.   Kroil doesn't seem to be sold here. Other penetrating oils are of course, though I've often used kero for this. WD40 aka white spirit is popular here. I've no clue where my plusgas cans are, not seen them in a long time. So yes I probably need to buy some. I normally try what I've got first.   Right now I'm in downtime, and it may take a while to heal up, so the Berninas will probably have to wait.     NT

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