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oldschool@tubes.com: Jul 16 03:36PM -0400 On Fri, 14 Jul 2017 20:51:30 -0400, "tom" <tmiller11147@verizon.net> wrote:     >Remove the capacitors and wash the board with detergent and warm water. Use >a brush to scrub where there is corrosion.   >Dry in oven at 50-60 °C for several hours.   I dont know if I'd place any electronics in an oven. Heat destroys components. Just sit it in the sun on a sunny day and it will dry. I have washed computer motherboards, including the power supplies, and hosed them off. (to remove all that dirt that builds up on that stuff), then left them out in the sun for a full day to dry, and they always work just fine.

Ralph Mowery <rmowery28146@earthlink.net>: Jul 16 06:48PM -0400 In article <irfnmclaqsfrc3do6o7j9vrt11157fgaie@4ax.com>, oldschool@tubes.com says... > hosed them off. (to remove all that dirt that builds up on that stuff), > then left them out in the sun for a full day to dry, and they always > work just fine.   My oven will not regulate that low, so I put the wet equipment in a car that is out in the sun in the summer.

ABLE1 <someone@nowhere.net>: Jul 16 08:09PM -0400 On 7/16/2017 6:48 PM, Ralph Mowery wrote: >> work just fine.   > My oven will not regulate that low, so I put the wet equipment in a car > that is out in the sun in the summer.   Ah ha!! The discussion continues....................... COOL!!!

Jeff Liebermann <jeffl@cruzio.com>: Jul 16 10:50AM -0700 On Sun, 16 Jul 2017 13:29:07 -0000 (UTC), Chris <cbx@noreply.com> wrote:   >measuring the total resistance of a circuit with a) a DMM and b) an old >analog meter with a physical needle. And this doesn't only happen at high >impedance points, either. What could account for this?   If you're doing in circuit resistance measurements, you're probably measuring the resistance of a non-linear device such as a transistor or diode. These will show different resistances at different applied voltages. Umm... this assumes that you've unplugged the circuit that you're testing and have discharged any BFC's (big fat caps).   Disconnect whatever you're measuring. Take one of the DVM's that has the highest input resistance, set it to VOLTS, and measure the VOLTAGE across the leads of the other meters. You'll find quite a bit of variation. My guess(tm) is that the meter with the highest voltage, will read the lowest resistance.   If you have an ESR (equivalent series resistance) meter, you can do in circuit low resistance measurements without worrying much about the effects of semiconductors. That's because the voltages involved are so small, that the semiconductor doesn't even being to conduct, and is therefore essentially out of the circuit.   There's really no way to "fix" the problem of measuring in circuit resistances. If I want to accurately measure a resistor that's in a circuit, I usually have lift one lead, and measure only that resistor. >I've got four DMMs and two analogs. The DMMs agree with the other DMMs >and the analogs agree with each other. But the different types don't >agree with each other!   The analog meters (VOM) require more current in order to obtain a resistance reading. More current means more applied voltage across the leads, which means that the semiconductors in your test circuit are well into conduction. Try measuring a resistor and diode in parallel and you'll see the problem in action.   -- 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

oldschool@tubes.com: Jul 16 02:48PM -0400 On Sun, 16 Jul 2017 15:05:34 -0000 (UTC), Cursitor Doom >which is more than enough to turn on those semiconductors, but also more >than enough to destroy a lot of chips that can't tolerate much more than >5V. Horses for courses/different strokes and all that.   I have heard this several times about analog meters destroying chips, because the chips cant tolerate over 5v. At the same time, I have never seen any analog meter using more than two batteries. That's 3 volts. I have several analog meters and they all use two AA batteries. Except for the one mini meter which only has only one AA battery.   So we have this theory about these analog meters ruining chips for exceeding 5v, but none of the meters can provide more than 3volts. This makes me think that this theory is based on advertisers trying to sell digital meters, or just an old wives tale with no backing. (Unless there are some analog meters which use 4 batteries [6volts], or use a 9v battery). If meters do exist, which are powered by more than 3v, I have never seen them.

Jeff Liebermann <jeffl@cruzio.com>: Jul 16 01:20PM -0700 >seen any analog meter using more than two batteries. That's 3 volts. >I have several analog meters and they all use two AA batteries. Except >for the one mini meter which only has only one AA battery.   The Simpson 260 VOM used a single D cells and a 15V battery (Eveready 417) for the Rx10K range. Later models switched to a 9V battery and then to 4ea AA batteries. The Triplett 630 used a single D cell and a 30V (Eveready 413).   -- 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

oldschool@tubes.com: Jul 16 03:46PM -0400 On Sun, 16 Jul 2017 13:20:54 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:   >417) for the Rx10K range. Later models switched to a 9V battery and >then to 4ea AA batteries. The Triplett 630 used a single D cell and a >30V (Eveready 413).   Ok, I guess you have meters that I've never seen. I have to wonder why they need such high voltage to measure resistance. However, I would not use those meters on modern circuits if I owned them.   My analog meters are all older Radio Shack meters, which I have owned for many years. All (except the mini), have two AA batteries.   I also have a few VTVM's. I am not sure what they output, so I dont use them on any solid state devices. But they are well suited for tube gear, and can handle the high voltages in tube gear, which a lot of the battery operated portable VOM's cant handle.

John-Del <ohger1s@gmail.com>: Jul 16 02:27PM -0700 On Sunday, July 16, 2017 at 4:50:45 PM UTC-4, olds...@tubes.com wrote: But they are well suited for tube gear, > and can handle the high voltages in tube gear, which a lot of the > battery operated portable VOM's cant handle.   Maybe the Harbor Freight free-with-any-purchase DMM can't handle higher voltage, but I've never seen any DMM that can't handle tube gear voltages. If you're talking about the old plate voltages of the horiz output or HV rectifier tube in televisions, no meter without an accessory HV probe will read those without some damage.   Unless you're doing peak and null, you shouldn't be using your analogue meters in my opinion.

Cursitor Doom <curd@notformail.com>: Jul 16 09:24PM On Sun, 16 Jul 2017 15:46:36 -0400, oldschool wrote:   > Ok, I guess you have meters that I've never seen.   You've never seen any AVO/Megger meters?? Like this for example:   http://www.ebay.co.uk/itm/Bakelite-AVO-Model8-MK5-Multi-Meter-Excellent- Condition-100-Tested-/152599935777?hash=item2387aa3b21:g:1csAAOSw241YZTX1   They've been exported all over the world for decades!   They typically use one 15V battery (about the size of a AA cell) and a single 1.5V D cell.

Ralph Mowery <rmowery28146@earthlink.net>: Jul 16 05:52PM -0400 In article <g7cnmc110cdt64ldsvmj3if2ed5f1jr06l@4ax.com>, oldschool@tubes.com says... > are some analog meters which use 4 batteries [6volts], or use a 9v > battery). If meters do exist, which are powered by more than 3v, I have > never seen them.     The Simpson 260 series used a 1.5 V D cell and several voltages for the highest resistance range. Very old ones used a 15 volt battery I think, some used several AA batteries and the two I have use a standard 9 volt battery. Tripplit made a similar VOM. I have not looked inside one of those, but would bet it had 2 batteries similar to the Simpson.   The caution before ICs came out was not to use the lowest current range for solid state devices. That 1.5 volt battery could supply enough current to destroy some simiconductors. Not voltage, but current.   The caution was way before the DMMs and ICs came out.

Ralph Mowery <rmowery28146@earthlink.net>: Jul 16 06:37PM -0400 In article <s5gnmcl9ukiegiv2q861m73b2ih8mll1ev@4ax.com>, oldschool@tubes.com says... > them on any solid state devices. But they are well suited for tube gear, > and can handle the high voltages in tube gear, which a lot of the > battery operated portable VOM's cant handle.     Radio Shack tells all. Anyone that says old school should have heard of and maybe used the Simpson or Tripplit meter. Don't recall the number of the Triplett as I only used one in school over 40 years ago.   The RS meters may have a meter of around 30 uA and the others have 50 uA meters. It takes more voltage to operate them in the higher resistance ranges. I don't know what the RS meters have for full scale of the resistance ranges, but it may not be as much.   Even the Free HF meter I have says it will do 1000 VDC and 700 VAC. Not too much common tube equipment has voltages over that, unless much higher and special HV probes are needed. I think my old Heathkit VTVM may do 1500 Volts. Have not had it out in years except to give it a check a year or two ago to see if it still works.

Jeff Liebermann <jeffl@cruzio.com>: Jul 16 04:30PM -0700 >Ok, I guess you have meters that I've never seen.   You haven't seen any of these? <http://www.simpson260.com> <https://www.google.com/search?tbm=isch&q=simpson+260> These were probably the most common VOM's available. At one time, I had about 5 of them. They've been replaced by more modern meters, but I still keep one of them on the shelf, just in case.   >I have to wonder why >they need such high voltage to measure resistance. However, I would not >use those meters on modern circuits if I owned them.   Most (not all) VOM's did NOT have amplifiers with gain. Therefore, resistance measurements needed to be using the basic meter sensitivity. The meter sensitivity and battery voltage put a limit on the highest resistor value that could be accurately measured.   The meter face usually had the meter sensitivity. In this example: <https://cdn6.bigcommerce.com/s-a1x7hg2jgk/images/stencil/500x659/products/42383/204330/50126_2__62784.1490313691.jpg?c=2> It says "20,000 ohms per volt" (on DC scales) which is the same as: 1 / 20K ohms/volt = 50 渙 full scale You could probably read 1/10th of full scale accurately. So, what's the largest resistance that you could read at 1/10th of full scale, using a 9V battery? R = E / I = 9V / 5*10-6A = 45M Good enough to measure common resistors of the 1960's. However, if you tried it with a 1.5V battery, you would get: R = E / I = 1.5 / 5*10-6A = 7.5M That's too low, because there were plenty of resistors up to 22M in older tube sets, that such a meter could not measure.   -- 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

tabbypurr@gmail.com: Jul 16 04:34PM -0700 > >417) for the Rx10K range. Later models switched to a 9V battery and > >then to 4ea AA batteries. The Triplett 630 used a single D cell and a > >30V (Eveready 413).   Many old meters used 9v or 15v batteries as well as a 1.5v.   > Ok, I guess you have meters that I've never seen. I have to wonder why > they need such high voltage to measure resistance.   To enable the highest R range to work   > However, I would not > use those meters on modern circuits if I owned them.   they're fine, just don't use the top R range on anyhing delicate.   > them on any solid state devices. But they are well suited for tube gear, > and can handle the high voltages in tube gear, which a lot of the > battery operated portable VOM's cant handle.   voltmeters don't output anything. They should be fine measuring solid state.     NT

Ralph Mowery <rmowery28146@earthlink.net>: Jul 16 07:54PM -0400 In article <easnmcp9is7gu1eiqbu0bs76i89dhsqi4f@4ax.com>, jeffl@cruzio.com says... > R = E / I = 1.5 / 5*10-6A = 7.5M > That's too low, because there were plenty of resistors up to 22M in > older tube sets, that such a meter could not measure.   The Simpson did have a 20 meg mark on the scale. It is almost worthless at that resistance. About all that can be told is that the reistor is not totally open. Around 2 to 5 meg ohms is abut the best anyone can tell close to the resistance. The resistance scale is similar to a log scale so as the resistance value goes up and below about 1/4 scale the values start getting very close together.   I have not looked into the 260 working in many years. I know of the 20 K per volt and how it works on the DC ranges, but not sure where it comes into play on the ohms scale for this meter.   The meter movement is just under 50 uA and has a pot that I think goes across it so the first step in calibrating one is to set it for 50 uA full scale.

Cursitor Doom <curd@notformail.com>: Jul 16 11:55PM On Sun, 16 Jul 2017 16:34:56 -0700, tabbypurr wrote:   > voltmeters don't output anything. They should be fine measuring solid > state.   DMMs and VOMs give different readings in certain circumstances (see Ralph's post). In GB (at least) for a long time the service manuals for decent gear would provide expected voltage readings for 20k OpV analogue meters, the AV0 model 8 specifically IIRC, which saved the technician the extra bother of scratching his head when checking hi-z parts of a circuit.

Jeff Liebermann <jeffl@cruzio.com>: Jul 16 10:36AM -0700 >> (negative voltage detection) mechanism used to detect EoC >> (end-o-charge), which can easily overcharge a NiMH cell or battery.   >My cordless phones use NiMH with no charge control.   Maker and model please. I want to see if I can find a schematic.   >get charged or discharged all the time. Last set of cheap >cells lasted at least 1500 cycles. So you can do it. >NT   I hate to admit it but you are probably correct.   My AT&T EL52210 Dect 6.0 handset <https://www.google.com/search?q=at%26t+el52210&tbm=isch> uses two AAA 2.4v 400ma-hr NiMH cells. The battery label demands that I charge the battery for 16 hrs prior to use. Doing the math and assuming constant current charging, that's a C/16 charge rate.   I disassembled the charger base and took some photos: <http://www.11junk.com/jeffl/pics/repair/AT-T%20charger%20base/index.html> Not much inside. 6VAC 300ma wall wart, diode bridge, filter cap, and some unidentified diodes and transistor. I'll trace out the circuit and identify the parts if I have time. Without an IC to do the NVD detection, this charger is rather crude and probably does not follow the recommendations from the Battery University site.   Incidentally, the phone is 5 to 8 years old and shows no sign of battery problems. The handsets spend most of their life in the charger base and the batteries have never been discharged to the point where the handset complains. Open circuit battery voltage is now 2.68V which is very much full charge for NiMH.   Very strange.     -- 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

oldschool@tubes.com: Jul 16 03:32PM -0400 On Sat, 15 Jul 2017 18:12:14 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:     >Those are LiPo (lithium polymer) batteries, normally used in cell >phones and quadcopters. Photos: ><https://www.google.com/search?q=lithium+polymer+batteries&tbm=isch>   Yep, that's what they look like. I have never seen these before now...     >You'll also need specialized tools to build and repair those, such as >a hot air desoldering station, reflow oven, solder paste, and various >chip manipulation tools.   Yep, I'm sure they sell all this stuff, but I'm not investing the money in it. I'd probably spend several hundred dollars to get all this stuff, then spend a thousand dollars to my eye doctor for eye strain, trying to see these parts. Then I'd remove parts, which are not labeled, and after wasting hours trying to understand it, I'd still end up tossing it in the trash. I think I spent around $25 for this charger, and dont think I got my money's worth out of it, but I am fully aware it is not meant to be repaired. Like most stuff these days, it's disposible.   I'm not even considering repairing it, I just want to salvage the solar cell and make use of it.   I should also mention that last winter Walmart had some portable cellphone chargers that are meant to be used when the phone's battery dies. You charge these power packs by connecting them to any phone charger or USB port. These battery packs sold for $6. I bought two of them. If I plan ot use my phone in a place that has no means to recharge the phone's internal battery, I just carry these power packs in my pocket.   I thought the solar charger was better, but since it did not last even a year. I spent close to $20 to save about 50 cents worth of electricity to recharge a battery pack.     >Yes, a solar charge controller. What type and size depend on the >ratings of the solar panel and LiPo battery, neither of which are >currently well defined.   So, does this have to be designed by hand with individual components, or is there a chip available that does it all? -OR- can a ready made board be purchased that is intended to control solar chargers?   >They also do a great job of killing batteries. LiPo lasts longer than >most, but few batteries will last very long after being cycled between >full charge and total discharge every day.   I have to disagree about these solar lights killing batteries. I have several of these lights mounted on my house, and several more on my workshop shed. I paid from $5 to $10 for them. I attach them with 1/2" conduit straps to the wall. Some of them have lasted 5 years, others have died after 2 years. But considering they are charged and drained 365 times each year, and operate off of one NiCd battery, I really cant complain, about their life expectancy. Every so often a local store sells replacement batteries in a 4 pack, ON SALE for about $6. So, for $1.50 per light, I just replace the dead batteries, and get another two or more years from the lights.   Now, if you buy those solar lights that cost $1, they DO NOT last long. And I also found that if you stick them in the ground along a sidewalk, they get broken faster than the batteries die, and if you dont step on them or chop them up with the lawn mower, they wont survive the snow in winter. Wall mounted is so much better, and in my case they perform an inportant task, they light up the stairs by my door, without needing to operate an AC porch light, which will cost a lot more on the electric bill.   >>from back-flowing into the solar panel.   >True. Schottky diode for minimum voltage drop. It's often inside the >charge controller chip.   So, would one of these diodes be all that I really need to use this solar panel?     >>Anyhow, what is needed to attach this solar panel to a common >>rechargable AA or AAA battery?   >Better numbers.   I guess you mean I need to determine the output of the solar panel. I'll have to see what I can measure.

Ralph Mowery <rmowery28146@earthlink.net>: Jul 16 06:46PM -0400 In article <ivdnmc9dusaujffjnfnie4596p61os5l4l@4ax.com>, oldschool@tubes.com says... > the trash. I think I spent around $25 for this charger, and dont think I > got my money's worth out of it, but I am fully aware it is not meant to > be repaired. Like most stuff these days, it's disposible.   A couple of years ago I decided I needed to get set up for the small stuff. As this is just a hobby I bought some inexpensive gear. The 10 x stereo microscope was the most at $ 200. The a hot air rework station with a small soldering iron was another $ 60. Then about $ 800 for solder wick, solder paste, tweezers and a few other things. The most expensive was the pound of.015 inch solder that will last me a lifetime.   I agree, many things are not made to be repaired. The parts cost more than a new item. Like one older battery drill. The batteries would not hold a charge. For slightly more than one battery, I bought another drill of better quality that had 2 batteries.

tabbypurr@gmail.com: Jul 16 04:41PM -0700 On Sunday, 16 July 2017 18:36:48 UTC+1, Jeff Liebermann wrote: > where the handset complains. Open circuit battery voltage is now > 2.68V which is very much full charge for NiMH.   > Very strange.   BT graphite 1100 series. I saved you the time & googled, no trace of a circuit anywhere. So I could be wrong, but I'd be surprised if there were any charge control electronics in such equipment. Such non-ideal battery charging schemes are widespread, more or less universal really, in many types of equipment.     NT

tabbypurr@gmail.com: Jul 16 04:44PM -0700 > >charge controller chip.   > So, would one of these diodes be all that I really need to use this > solar panel?   any diode, doesn't need to be schottky. But you've still got to get the numbers right. Start with measuring the panel's offload voltage & short circuit current in full sun.     NT

gomes.ee@gmail.com: Jul 16 03:28PM -0700 > > There is nothing in the user manual about this problem.   > > Any help?   > > TIA   I have tried this, But after i turn off the receiver it comes back on the same. And i do the ip reset again. Any permanent fix?

jamesriico@gmail.com: Jul 16 01:24PM -0700 I need help

John-Del <ohger1s@gmail.com>: Jul 16 02:22PM -0700 > I need help       Minister, Rabbi, or Priest would be my best advice..

oldschool@tubes.com: Jul 16 03:00PM -0400 On Sat, 15 Jul 2017 20:01:24 -0700, "David Farber" >:Y1 and the other pair is marked, :Y2 Any ideas what kind of transistors or >other three-terminal devices these are?   >Thanks for your reply.   My cats are just plain old fashioned farm cats who only need a common mouse to keep them entertained. The mice dont contain any motors, transistors, capacitors, or batteries. Low tech, and much better for the environment.   But these modern city cats have gone high tech. Some even have smartphones, and have their own facebook pages. Thats the problem, They expect their owners to provide electronic gadgets to entertain them, then they dont even earn their "pay" to cover the cost of the batteries for these gadgets, because they dont kill any mice.   I say, the solution is to just toss all the electronics and buy your cat a plain old mouse. If the cat refuses to play with the mouse, trade that citified cat for a plain old fashioned farm cat. Farm cats earn their living, and they still have the balls to tackle the biggest mouse or even a rat. Most of these modern citified cats dont even come with balls anymore.   Geez, I just could not resist posting this reply! :)   On a serious note, I cant see the need for any transistors to operate a small battery operated DC motor, unless it has some sort of speed control, or reverses or something like that. I guess you will have to determine what this toy does, besides just rotate. Like most cheap modern stuff, they no longer label components. That fact alone, combined with the small size of these parts, is one reason I prefer working on old tube gear. Maybe someone else on here can point you in the right direction regarding that transistor. I cant....

John-Del <ohger1s@gmail.com>: Jul 16 12:06PM -0700 On Saturday, July 15, 2017 at 3:48:17 AM UTC-4, micky wrote:   > work.   > But it runs very well, very quiet, and very smooth, and only has 95,000 > miles.     Around these parts folks'll pay 1000 for a non running Toyota rusted to the ground (most of them around here do after 5 years). A running yota with only 95K miles will bring three times that even needing a roof. Gotta be worth that parted out. Where you going to find a 2000 Toyota engine and tranny for that kind of money. Are you sure that's all it will bring?

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