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Cursitor Doom <curd@notformail.com>: Jul 11 05:43PM On Sat, 11 Jul 2015 10:10:40 -0400, Pat wrote:   > Some supplies will not regulate voltage without a load. Try measuring > it again with a small load (eg, a 1K resistor) across the supply.   Good point! Still doesn't check-out, though. Rated current at 12V is 500mA, so a 50 Ohm resistor would be more appropriate. Managed to find a 47R power resistor and connected across supply. Now reading 14.45V, so deffo not right...

Dimitrij Klingbeil <nospam@no-address.com>: Jul 11 10:40PM +0200 On 11.07.2015 19:43, Cursitor Doom wrote: > 500mA, so a 50 Ohm resistor would be more appropriate. Managed to > find a 47R power resistor and connected across supply. Now reading > 14.45V, so deffo not right...   AOR Japan - that supply is for a radio, right?   That reminds me of the (maybe similar) power supply of another radio. Last year I bought a Yupiteru MVT-7500. It's a small handheld radio with a 100 kHz to 1.3 GHz continuous frequency range, operable from either 3 AA cells or an external power supply. It came with a linear PSU, rated for a 100 V AC mains input (Japanese) and a 12V DC output.   At least, 12V DC is what's printed on it. Since I don't have a 100 V mains socket at home, I couldn't test it right away - had to get a 230 to 2x48 V transformer first, and use the secondaries in series (96 V nominal) as a practical approximation. Unloaded it happens to be slightly over 100 V, but should be within usual tolerances. When I plugged the Yupi's power supply into it and checked the output with a multimeter (unloaded), it went up over 17 V! At first I thought my improvised primary supply was iffy, but nope, the primary was OK.   Then I tried loading it and it just barely got near its rated output under maximum rated load of 200 mA. But since the radio never really uses the full 200 mA anyway - either 80 or 150 mA depending on the state of the LCD backlight - the power supply voltage is much higher. It seems to run at just over 15 V, more or less, under "real life" conditions and never gets down to 12 V with the radio as a load.   Apparently here the PSU has just a transformer, a bridge rectifier and a cap - nothing else, all the regulation is done in the radio.   Yours may be similar. Btw, was yours also rated for 100 V and did you plug it into 115 V by any chance? If so, consider getting it a "properly" rated supply. The Japanese have a 100 V mains, so when they write 100 V, they actually mean it. Using the PSU on 115 V may work, but it could likely stress components in the radio if connected like this for a significant period of time.   Regards Dimitrij

"Gareth Magennis" <sound.service@btconnect.com>: Jul 11 10:42PM +0100 "Cursitor Doom" wrote in message news:mnr1b3$12g$1@dont-email.me...   Hi all,   Just before I connected up the PSU to this AOR comms rx I'd bought, I thought I'd best double check the polarity was right, because someone for some reason had spliced the cable at some time and put a new plug on it. ON checking, I noted that though the polarity was correct, this psu was putting out 19.33V - whereas it's rated output was stated as 12V! This is not some cheap Chinese psu; it's the original AOR Japanese psu made by them (or at least badged by them) for this receiver. What could cause it to go from 12 to more than 19V? Don't these wall-wart style supplies have over-voltage protection/crowbars, FFS??   Just curious...         Just curious, is this Wall Wart just a transformer in a plastic case? Any 12v transformer unloaded will put out a lot more than its rated voltage.   19v doesn't sound that unlikely to me if that is what it is.     Gareth.

John G <john.g@green.com>: Jul 12 10:48AM +1000 Dimitrij Klingbeil expressed precisely : > connected like this for a significant period of time.   > Regards > Dimitrij   And isn't the nominal in USA 120volts these day? :-Z   The Japanese 100Volts was a problem in the early days of PCs as many people thought it was the same as USA whereas only military bases had USA power. Some of Japan is 60 hz and some is 50Hz   -- John G Sydney.

Cursitor Doom <curd@notformail.com>: Jul 12 11:05AM On Sat, 11 Jul 2015 22:42:47 +0100, Gareth Magennis wrote:   > Just curious, is this Wall Wart just a transformer in a plastic case?   Eh?? Have you actually read the thread?

Cursitor Doom <curd@notformail.com>: Jul 12 11:12AM On Sat, 11 Jul 2015 22:40:48 +0200, Dimitrij Klingbeil wrote:   > AOR Japan - that supply is for a radio, right?   Correct. A "communications receiver" so-called, though it's only the size of a half a shoebox. I'm more accustomed to rack-mounted Racals so please forgive my cynicism. ;)   > a 100 kHz to 1.3 GHz continuous frequency range, operable from either 3 > AA cells or an external power supply. It came with a linear PSU, rated > for a 100 V AC mains input (Japanese) and a 12V DC output.   This one is specifically made for this receiver. It even has the pin-outs for the rx's power socket printed on it. And it's been manufactured for the UK market. It states 230VAC input; 12VDC @ 500mA output; 12VA rating. And, "Made by AOR Communications, Tokyo, Japan" under the spec. Could not be clearer!

"Gareth Magennis" <sound.service@btconnect.com>: Jul 12 12:30PM +0100 "Cursitor Doom" wrote in message news:mnthlo$noo$1@dont-email.me...   On Sat, 11 Jul 2015 22:42:47 +0100, Gareth Magennis wrote:   > Just curious, is this Wall Wart just a transformer in a plastic case?   Eh?? Have you actually read the thread?         OK, so just a transformer with rectifier diodes and a cap, i.e. not regulated, and not an SMPS.     Gareth.

John-Del <ohger1s@aol.com>: Jul 12 06:21AM -0700 On Saturday, July 11, 2015 at 1:45:09 PM UTC-4, Cursitor Doom wrote: > Rated current at 12V is 500mA, so a 50 Ohm resistor would be more > appropriate. Managed to find a 47R power resistor and connected across > supply. Now reading 14.45V, so deffo not right...     If the supply is rated at half amp at 12V, a 27 ohm 10 w resistor will give you a better idea of the supply.   As Gareth pointed out, this is probably just an AC xfr, rectifier, filter. Not a smps and not regulated.   If you're unsure about the radio's capability of internally regulating the input or not loading the supply down sufficiently to keep the voltage in the 12-14v range, then replace it with something more appropriate or add an external series pass 12V regulator IC.

Cursitor Doom <curd@notformail.com>: Jul 12 02:29PM On Sun, 12 Jul 2015 06:21:15 -0700, John-Del wrote:   > If the supply is rated at half amp at 12V, a 27 ohm 10 w resistor will > give you a better idea of the supply.   I used 47R because it gives rise to half the rated output current, which I thought would be about right for a conservative design POV. No decent designer, surely, is going to specify a 500mA PSU for a load requiring 500mA of current. Absolutely maxed-out!   > the input or not loading the supply down sufficiently to keep the > voltage in the 12-14v range, then replace it with something more > appropriate or add an external series pass 12V regulator IC.   I've got it running off a big ol' linear supply at the moment. Just out of curiosity I'll see how much current it's drawing. Should it turn out to be only around 150-250mA - as I suspect - then we'll know for sure that wall wart is f*cked. I reckon if I scoped the PSU output I'd see pure sine waves!

John-Del <ohger1s@aol.com>: Jul 12 08:17AM -0700 On Sunday, July 12, 2015 at 10:30:45 AM UTC-4, Cursitor Doom wrote: > I thought would be about right for a conservative design POV. No decent > designer, surely, is going to specify a 500mA PSU for a load requiring > 500mA of current. Absolutely maxed-out!   Yeah, but you're missing the point. An unregulated wall wart is rated for the max current that the supply will output no less than 12V.   If your radio has regulators inside that can handle an input of 19.33 volts, then there's no problem. If the radio was designed to run on batteries and/or a regulated supply, then you should definitely go to a regulated supply, or add a post regulator to the wall wart.

Cursitor Doom <curd@notformail.com>: Jul 11 05:25PM Hi all,   Forgive me for not having very much useful detail on this, but a friend has a scope that's unfocusable and produces a thick trace. My immediate reaction was maybe noise getting into the signal path from a faulty mains filter or maybe an internal component in the smps section failed, but he reckons he's ruled out the latter as apparently it's a linear supply. He doesn't have another scope to check the rails for noise with so he's kind of limited. Anyway, that was only my hunch, I don't know the precise model of scope this is; I just wondered if anyone would like to toss in their 2c worth if they've encountered this issue themselves and what might be the cause of it? thanks, cd.

all2001@spambog.com (Wolfgang Allinger): Jul 11 01:47PM -0300 On 11 Jul 15 at group /sci/electronics/repair in article mnrjif$2bm$1@dont-email.me   >Forgive me for not having very much useful detail on this, but a >friend has a scope that's unfocusable and produces a thick trace.   Check the supply for the Wehnelt cylinder, PWR dead, bad contact, broken cable...   https://en.wikipedia.org/wiki/Wehnelt_cylinder     Saludos (an alle Vernünftigen, Rest sh. sig) Wolfgang   -- Wolfgang Allinger, anerkannter Trollallergiker :) reply Adresse gesetzt! Ich diskutiere zukünftig weniger mit Idioten, denn sie ziehen mich auf ihr Niveau herunter und schlagen mich dort mit ihrer Erfahrung! :p (lt. alter usenet Weisheit) iPod, iPhone, iPad, iTunes, iRak, iDiot

c4urs11 <c4urs11@domain.hidden>: Jul 11 06:29PM On Sat, 11 Jul 2015 17:25:35 +0000, Cursitor Doom wrote:   > might be the cause of it? > thanks, > cd.   Anything Tek one address: https://groups.yahoo.com/group/TekScopes   Cheers!

whit3rd <whit3rd@gmail.com>: Jul 11 10:09PM -0700 On Saturday, July 11, 2015 at 10:27:04 AM UTC-7, Cursitor Doom wrote:   > Forgive me for not having very much useful detail on this, but a friend > has a scope that's unfocusable and produces a thick trace. My immediate > reaction was maybe noise   Probably not. Noise, if you mean interference, would be affected by change of timescales. More likely, a HV electrode in the electrode gun is used for focus, and the adjustment is off because a high-ohms fixed resistor has failed, open circuit. Look for range-setting fixed resistors connected to the focus control, taking all precautions against HV and breakage of the glass...

"Mark Zacharias" <mark_zacharias@labolgcbs.net>: Jul 12 07:30AM -0500 "c4urs11" <c4urs11@domain.hidden> wrote in message news:1436639380.773261@news.evonet.be...   > Anything Tek one address: > https://groups.yahoo.com/group/TekScopes   > Cheers!   Well, there's no real substitute for actual troubleshooting - but having said that, I understand some Tek's have had bad focus potentiometers, and there's always the possibility of a bad high-value resistor in such a circuit. A bad 2.2 meg resistor caused a B&K 'scope of mine to not quite focus. The focus pot ran out of range first. Replacing the resistor fixed it.   If you do attempt to troubleshoot, be aware there are some rather high voltages in such circuits.     Mark Z.

Cursitor Doom <curd@notformail.com>: Jul 11 05:45PM On Sat, 11 Jul 2015 07:04:05 -0700, Phil Allison wrote:   > are *on the way out* as well as obviously dead ones.   > If in doubt, comparison with a the closest new electro available is a > good move.   Well maybe. But it'll slow the process down massively as it's not just the capacitance that causes ESR values to change. As you well know.

Jeff Liebermann <jeffl@cruzio.com>: Jul 11 11:30AM -0700 On Fri, 10 Jul 2015 22:17:55 -0700 (PDT), Phil Allison   >** How absurdly lazy, zeroing only takes one or two seconds >and does not need to be repeated unless the meter is switched off. >All ESR readings are virtually instantaneous after that.   The banana or pin jacks found on some ESR meters, including my Dick Smith K-7204, do not make a reliable connection. The associated probes are not much better. If I move the leads, I'll see some variations in reading from the change in lead resistance. However, you're correct about me being lazy. I should have soldered the jacks and the probes long ago. (Added to things to do list for today).   >If the cap is being tested out of circuit, no leads are normally needed.   I do test caps out of the circuit, but only after I've unsoldered them from the PCB. That's to verify that they really were bad. Other than that, I rarely measure individual components, except when the markings have disappeared. 2 of my 3 ESR meters have soldered leads. It will shortly be 3 of 3 making measurements without test leads impossible.   >> Good enough for testing electrolytic capacitors,   >** No it isn't.   >The ESR of most electros of over 1000uF is under 0.05 ohms.   It can become a problem with the Cap Wizard at 100 uF. See the manual at: <http://midwestdevices.com/_pdfs/Capmanual9.pdf> See the table of "Capacitor Types and Expected ESR - 1uf & up" For 1 uF and up, they consider anything less than 3 ohms as good. However, you're correct. When I measure a BFC (big fat capacitor), usually in a power supply, a digital meter is needed. I use this chart for reference: <http://802.11junk.com/jeffl/crud/ESR.txt>   There's also some interesting stuff in the Cap Wizard manual on measurements with parallel inductance and resistance.   -- 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

"Ralph Mowery" <rmowery28146@earthlink.net>: Jul 11 10:57PM -0400 "N_Cook" <diverse@tcp.co.uk> wrote in message news:mnqp40$9qv$1@dont-email.me... > requirement as most of my testing is in-circuit , unlike the shown > examples of isoltated componenent testing. Must be no more than .2V and > ideally .1V, so as not to turn on anything active, in circuit   The fleabay one uses the same basic circuit design as the Peak meter. Peak is screwing the people as they make one for non simiconductor devices and another one for simiconductors. Whe ebay one does both and the origional software for them does both using the same circuits.   I don't know the specs for it, but I did put it on a analog scope and from what I can tell when I hook a capacitor across it there is a large voltag pulse around 4 votls or so and then a low voltage pulse of about .2 volts. Both going +and -.

Phil Allison <pallison49@gmail.com>: Jul 11 10:06PM -0700 Cursitor Doom wrote:   > > good move.   > Well maybe. But it'll slow the process down massively as it's not just > the capacitance that causes ESR values to change. As you well know.     ** See page 9 of the Peak ESR meter user's guide.   http://www.peakelec.co.uk/resources/esr60_userguide_en.pdf   The ESR values shown in the table up to 470uF are several times higher than normally found with new caps of the same ratings.   When servicing, the task is to identify electros whose ESR has risen significantly, indicating end of useful life. Cos most of the electrolyte that was there when new has escaped and evaporated.       .... Phil

N_Cook <diverse@tcp.co.uk>: Jul 12 08:30AM +0100 On 12/07/2015 03:57, Ralph Mowery wrote: > what I can tell when I hook a capacitor across it there is a large voltag > pulse around 4 votls or so and then a low voltage pulse of about .2 volts. > Both going +and -.   Thanks for that, I suppose at that price its worth getting as a spare/second opinioner. My old one is 15KHz sine , or was before clamping with reversed germanium diodes across the probes, to limit the applied voltage, but it is good enough for go/no-go of >5uF or so electros.

Cursitor Doom <curd@notformail.com>: Jul 12 11:20AM On Sat, 11 Jul 2015 22:06:30 -0700, Phil Allison wrote:   >> the capacitance that causes ESR values to change. As you well know.   > ** See page 9 of the Peak ESR meter user's guide.   > http://www.peakelec.co.uk/resources/esr60_userguide_en.pdf   This bit makes no sense to me:   "To allow the self-protection mechanism to function, always ensure that the Atlas ESR has completed any analysis before connecting the test probes to a component." :-/

Veek M <vek.m1234@gmail.com>: Jul 12 08:16AM +0530 > beeps or whatever in a row, and then it repeats.   > If it does not do that, either the power supply, processor or motherboard > are bad. Hey jurb :) away from your usual haunts (freenode) - watcha doing here. Anyway, yep, that's how i did it (removed all the case wiring/drives). The thing is, the first time the mobo conked, the fan was defective.. i put in a new fan and the thing started up nicely.   What I don't understand is: 1. Is it normal for parts to drop dead like this: 1st the gfx card & fan - which feel like odd components to fail (the gfx card feeds of the PCIe but the fan ought to be way more robust). Then the mobo|cpu conked - the psu is fine, i swapped it out so unless it's (psu) generating transients..   2. How do I rule out the psu or wall power. I'll probably tell emm to get an i5 for gaming etc so obviously I don't want that to conk on my watch due to bad wall power.   I don't have a data logging multimeter but do those things record transients?   Also would a mobo tester help (me thinks that requires POST)

Jeff Liebermann <jeffl@cruzio.com>: Jul 11 11:01AM -0700 On Sat, 11 Jul 2015 04:07:45 -0700 (PDT), Jeroni Paul   >Nice project. Now I think of someone trying to increase its >range with a power stage and going way too far...   It's amazingly easy to do, but at 60 KHz, the range would be rather limited. It takes some serious power to produce a field strength sufficiently strong to overcome atmospheric noise levels.   >I guess something similar could be done to generate a DCF77/WWVB signal.   Yep. With a 1 baud data rate, it won't take much horsepower to generate the code. You can also buy IRIG-H (used by WWVB etc) time code generators that should work. <https://en.wikipedia.org/wiki/IRIG_timecode> For example: <http://www.gigatest.net/datum/tymmachine_7000.htm> Just add an AM modulated RF signal generator to produce the 60 KHz, and you're well on your way to becoming the local time lord.   >clock time. >That would help save battery since decoding a single minute would >be enough for safe daily sync.   Well, that would work, but there's an easier way. Since one frame is exactly 1 minute long, and there's no way to obtain identical data twice in a row, simply truncating the data to eliminate the minutes and seconds data, would give the clock an hour to obtain to identically truncated receptions. No need for a complex sanity check algorithm. Of course, the receiver would not be turned on for the full hour, but a successful spot check a few minutes after the first successful reception would be sufficient to conserve battery power. I suspect that's the way it's done in the C-Max chips, but I'm not sure.     Diversion: I worked on a failed proposal for an accurate time distribution system that used carrier current repeaters (i.e. HomePlug) to distribute the data. The time source was the GOES satellite system, which belched time sync data on 468.xxx MHz. The satellite data was to be retransmitted at the home or office over power line carrier current frequencies (now Home Plug) to any device that needs accurate time (clocks, computahs, appliances, test equipment, cell sites, SONET, etc). The difference with other radio clock systems is that this one would be continuous, not updated erratically. The GOES signal was strong (+45.5dBm EIRP) that a simple RHCP patch antenna aimed towards the bird was sufficient. I had it mostly working when NASA announced that it was going to pull the plug in 2004. Oh well. Today, it's done with GPSDO driven clocks with much better accuracy.   GOES time receivers. http://www.leapsecond.com/pages/goes/ TrueTime 468-DC GOES Time Receiver http://www.leapsecond.com/museum/468-dc/theory.htm 468-DC SATELLITE CLOCK http://www.ebay.com/gds/468-DC-SATELLITE-CLOCK-/10000000006640775/g.html Meteorological Satellite Frequencies <http://mdkenny.customer.netspace.net.au/metsat_frequencies.html#goes-n>   -- 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

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jul 11 03:02PM -0400 On 7/9/2015 11:18 PM, Jeff Liebermann wrote: > would move the main lobe sufficiently to miss the spacecraft. > <http://www.satsig.net/pointing/antenna-beamwidth-calculator.htm> > <http://www.uhf-satcom.com/misc/datasheet/dh2va.pdf>   Maybe so, if they'd lost their minds and were using their computer clocks to aim the DSN, but that's a fantasy. Orbital mechanics bods are all over this timekeeping stuff. It's the stupid software developers who don't know or don't care.   Cheers   Phil Hobbs   -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics   160 North State Road #203 Briarcliff Manor NY 10510   hobbs at electrooptical dot net http://electrooptical.net

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jul 11 03:06PM -0400 On 7/10/2015 3:34 AM, N_Cook wrote:   > IIRC the Etruscan day started at midday, the Jewish day at 6am, the > midnight start is just a hangover from the Romans, so sundown start is > no great problem   It is if it gets out of phase. There's no reason in the world to let it move at all--leap seconds keep civil time in synchrony with mean solar time to within a couple of PPM of a day.   Wanting to get rid of leap seconds is a classical example of a special interest group trying to seize control.   Not that that's unusual, especially these days.   Cheers   Phil Hobbs   -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics   160 North State Road #203 Briarcliff Manor NY 10510   hobbs at electrooptical dot net http://electrooptical.net

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