Re: HP 141T Power Supply Help Needed
No worries Mike.? You guys clearly have more experience.? I've just been doing my best to follow along.? I wanted to make sure I was understanding things correctly.? Seems like your close Bill!
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-Frank
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HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
Hello All,
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As a possible opportunity to upgrade my? test bench's HP 333A, I recently obtained a HP 339A distortion analyzer of unknown heritage, but very late serial number.
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Physically, not in too bad shape, all things considered:?
- missing bottom feet (not unusual, I suspect - probably was rack mounted) - I would be interested in finding these, if anyone knows of a source (new or used)
- missing end cap for input knob, otherwise all knobs complete (and not broken!)
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- Cleaned up well, internal inspection didn't reveal any previous obvious "tinkering", looked clean. Powered up and went through basic testing (using internal oscillator), seemed to mostly work but with the following observations:
1) Output monitor completely dead (not too worried about this yet)
2) Using the internal oscillator (1V output), for frequencies below ~3.5 KHz, the Freq. Input LED (counter clockwise) illuminates. I can extinguish the LED by moving the frequency vernier knob off of the "calibrated" detent position. If I do this, then all of the lower frequencies are reported to be in the notch filter's range and autoset works under this condition, depending on the actual frequency the vernier knob has to be set anywhere from just off the detent to about 2 o'clock max. As frequencies go lower than 3.5 KHz, the vernier has to be turned more CW. I've tried various voltage output settings (3, 0.1, .03) and the above behavior doesn't change as far as I can determine. Reported distortion values seem reasonably close (if not in,) to spec.
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What I've done so far:
- carefully deoxit only the metal contacts on all wafer switches (yes this took a while)
- re-seated the one board in a connector
- re-seated all cable and connectors
- loosened, re-tighted all mounting screws
- supplied missing endcap for input knob (my HP8640B parts bin had exactly one knob with the right cap size & color - from the output attenuator's center variable control, I believe)
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I am going to leave the unit powered up for a couple of days, it seemed like the longer it was on, the lower I could set the frequency and not have to use the un-calibrated vernier setting (capacitors reforming??) and see where it's at.
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- I have not compared it to my HP 333A yet, but I have hooked up a couple of other sig gens that I have just to see its operation, results seemed reasonable
- Other than the output monitor being dead, it seems like it just might need an alignment/calibration
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I have some equipment (HP pulse generator, scopes, freq. counters, etc.), but nothing calibrated by a lab, just a semi-serious hobby for me - testing/repairing my own stuff.
I have not looked at the supply rails with a scope yet, I have looked at the output - looks like a nice sine wave.
I will review the schematic for the output monitor, but I am not hopeful if it turns out to be an active device (finding replacement transistors are pretty much unobtanium nowadays, it seems).
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Suggestions , opinions on where to go next?
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sorry for the TL;DR
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Thanks,
Jim
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I gotta say, I just love seeing the gold PCB traces on this era's equipment - no tin-wiskers here! I smile every time I open up this type of equipment.
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Re: HP 141T Power Supply Help Needed
Frank, ? I appreciate your calculations.? Bill¡¯s problem is more fundamental than exact calculations would suggest.? It seems that since the voltage at C6 (the bulk capacitor) is so low (<1V) that there must be a wiring problem, or the diodes are bad, or the power transformer has a bad winding (which is very unlikely).? Bill says that he checked the diodes so the only thing left is a broken wire somewhere.? That is the way I see it. ? Mike ?
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From: [email protected] < [email protected]> On Behalf Of Frank Mashockie Sent: Saturday, September 7, 2024 12:29 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Wouldn't it be ~27VAC across the winding (11 and 13)? Or ~13.5VAC at both 11 and 12 and 13 and 12?? For a center tapped full wave rectifier Vout = Vp (sec)/2 - diode drop.? Since the center tap is -12.6V and you have 6.0VDC at the output, if we make -12.6V ground, you have Vout = 18.6VDC.? (18.6 + ~0.7)x2 = 38.6Vp.? 38.6 x square root 2 = 27VAC in rms across the winding from pins 11 to 13. Or am I missing something?
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Re: E4438c display problem, controler memory location please
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Re: Leaking alkaline cells
The whole discussion of battery reliability reminds me of another issue a couple of decades ago.?I was on a project that had to store many images in an image library. CDROMs were one option were they reliable?
I found a ?NIST? report on the archival properties of writeable CDROMs. They investigated many different types from many different manufacturers; some were useful for archiving within acceptable limitations, some weren't. From memory, the main parameters were the chemistry of the writeable layer, and the top-surface protective layer. The writeable layers came in a few colours. Some colours were always unusable, some were usable depending on the specific chemistry involved - but you couldn't tell the difference by simple observation. On top of that, each manufacturers tended to sell a variety of chemistries without specifying which you would get.?In essence the brands appeared to be little more than names applied to whatever they could source this month.?
Thus the only way to tell whether a batch of CDROMs was suitable for archival purposes was to test them for that. Not helpful.
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looking for a scan of the HP8901A pull out reference card
I am looking for a pull out reference card for the HP8901A modulation analyser.
Mine used to be rackmounted and lost its card in the mists of time. Now that I have repaired its PSU it is time to stick it into my ham shack.
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A ?hi-res scan would be great, who can help me please? Sofar drew blanks on Google e.a.
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Vy73 Wilko
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Re: Leaking alkaline cells
Morris,
I've just checked the pack I bought them in and it says (proudly and in several places) "Made in Germany" so it would seem the ones available in the antipodes are made to an inferior standard under licence - presumably - somewhere else on the planet. I can't ever recall having had an issue with Varta batteries and I use them preferentially in everything I value. Duracell really needs to take a long, hard look at itself.
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Re: Leaking alkaline cells
Forgive me if I missed something but I have not been following this thread very closely.
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I'm not saying they were wrong, but weren't environmentalists behind the EPA forcing removal of mercury from alkaline cells?? The mercury was present to reduce the tendency to evolve hydrogen gas which swelled the cells or caused them to leak.? 1996 time frame for enactment of the rule/law.? Link:
My memory is that was the beginning of the end for alkaline reliability.? It would appear that as with? Tetraethyllead in fuels, the industries never came up with a a good replacement for the environmental toxin they had to remove.? Some countries may still make cells with traces of mercury, the US pretty much banned it except for button cells.? Considering how many of those have leaked since the ban started I assumed they removed it from them as well.? Button cells almost never leaked, now leaks are common.? I don't know which or if all other countries have banned mercury in batteries.? China only banned it in 2021 (a 2017 law).
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I have a large number of dead alkaline cells in a jar many of them have leaked since they were removed but quite a few leaked before being fully depleted.? Both Duracell and Energizer batteries are leaking, more the longer they have been depleted.? I have seen leakage in a new cell from a large pack as well.? The variabil;ity is probably due to manufacturing process variations in the seals.? I had one small lot of batteries that all leaked shortly after depletion.? Fortunately I used most of those on my wireless mice and keyboards so they were removed before they leaked but they leaked before I put them in the recycle jar.? It took a couple of years to use them up, but the age didn't seem to matter, just once they were below 1 volt, leakage was imminent.?
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Clay
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Re: Leaking alkaline cells
I think the only Varta batteries I've used are for my watch and I think I got them from
Barry - N4BUQ?
"I don't know whether it's a manufacturing difference but down here in Australia my experience has been that Duracells are not as bad as some of the USA based commenters have described. The worst offenders I've had to clean up after are the "Varta" brand cells which I believe were originally from Eastern Europe but are probably made you know where.?
I won't have them in the house."
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Curious. My experience with Varta has been the polar (geddit?) opposite! I'm in Western Europe so perhaps the Varta batteries we get here are made somewhere else from the ones you get.
Duracell are still terrible here, though. I had a really powerful torch with an aluminium body which fell prey to leaks from Duracells and it very nearly destroyed the whole torch. Whatever that stuff that leaks is, it damn near welded the screw-on base to the barrel. I could only just get it free using a bench vice and a strap-wrench. IMO Duracells should come with diapers.
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Thanks Jinxie,
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I don't have any Vartas here in my recycle box but next time I'm at a store I'll check them out. I suspect they are made in China like just about everything else these days.
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Morris
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Hi Adri ? Here are the measurements connected to the first 2 converters as a reference. ? For the second converter I get a voltage of -1.678V instead of -3.5V as written in the service manual, I would say that we have similar voltages for this particular point. It seems far from the nominal point, but there may be an error in the manual. ? You are close to the goal, and this module may be repairable if there is no micro circuit, I have never opened a second converter in this series, but it is a possibility. ? When you open your second converter, send me pictures, I'm curious. ? Yves ? dear Yves, I didn't realize that you had made the measurements expressly to help me! I owe you then a double (even triple) thanks! Especially considering the fact that the front end of this instrument is really very dense, complicated and delicate! After my last email, in addition to doing the (essentially mechanical) intervention on the SYTF, I continued to check the input signal through the various sections by alternately injecting 300MHz @-20dBm and 5GHz @0 dBm The signals were found to be in specification up to the A3A9 bandpass (where the two paths join to form the intermediate frequency of 321.4MHz). At this point I could see the 5GHz signal (converted), present at that point at -47dBm (the specification says -43/-56dBm).
Instead, no trace of the 300MHz input signal
Investigatine?the second converter A3A4 in more depth
I checked?the signals at its input
On J1 there is 3.9214GHz at -46dBm? --->OK
On J3 there is 321.4MHz @ -37.7dBm? --->OK
On J4 I did not check 600MHz @-1dBm but the fact that the converter works in band 1 tells me that the oscillator is present and is in specification
The power supply is quite OK (5V are actually 4.75; 10V are 9.98 and the DC that controls the internal switch that should be +15V? (band 0) and -3.5V?(band 1) is actually +14.60V and -1.35V
This last value is rather far from the nominal and would have worried me BUT band 1 is exactly the one that works Conclusion: it would seem that the culprit is the second converter and in particular (probably) the internal switch that has the sole task of letting the signal? (which is already at 321.4MHz and does not need to be converted)?pass from its input to the output
In the next few days I will test the converter that meanwhile?has been?disassembled?; In the meantime I found a cheap one on the bay that should arrive in about ten days
Yves, I have a question: on the block diagram A3A4 is represented as a block that has 5 ports of which one (J5) would seem to be the connector that carries the power and the DC that controls the switch and that connects to A7 Analog Interface through the W35 cable
Actually,?this connector on the real component, does not have a name
Instead,?the name J5?, stamped on the case , indicates an SMB connector that has the writing LO TEST and in my analyzer?it is the one that?conveys the 600MHz LO signal? Now,?on the block diagram the connector that conveys the 600MHz signal has the name J4 (in my analyzer, the J4 connector was disconnected) This confusion of names and roles made me doubt that years ago, when I had disassembled this section I had not reassembled it correctly thanks again and best regards
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----- Messaggio originale ----- Inviato: 06/09/2024 23:21:52 Oggetto: Re: [HP-Agilent-Keysight-equipment] HP 5086-7906 YTO
Hi Adri, ? I had sent you the measurements of the RF input-output mixer signals verification, I had disassembled the High Frequency section of my 8595E to be able to provide you with this information. If you have no more questions relating to this section, I will close my 8595E and do a flatness check to see if everything is correct. ? Yves ? ? thank you very much for all the suggestions and information with which I will continue my investigation
In the meantime I received the 2.5mm socket wrench and after?a little mod to adapt it?for the purpose (photo), I proceeded to align the spheres of the SYTF
I must say that the operation done under the microscope is quite simple
The nuts must be loosened (not too much) and with a small screwdriver that acts as a delicate lever, ?the supports of?the?spheres can be moved so that the coupling ring completely shadows them (i.e. the sphere is exactly in the center)
Removing the gold mesh was not necessary
The insertion loss has improved enormously:
at 5 GHz it is -6dBm at 6GHz it is -10dB (before the signal starting from this frequency was no longer visible) at 6.5 GHz it is only -3dB
I will install it when I have solved the problem of "blindness" in band 0 since the calibration constants that the instrument has in memory (in practice the tuning current data) are relative to the original SYTF and the "new" SYTW requires a? SYTF CAL is done
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Re: Leaking alkaline cells
On Sat, Sep 7, 2024 at 07:55 PM, Jinxie wrote:
"I don't know whether it's a manufacturing difference but down here in Australia my experience has been that Duracells are not as bad as some of the USA based commenters have described. The worst offenders I've had to clean up after are the "Varta" brand cells which I believe were originally from Eastern Europe but are probably made you know where.?
I won't have them in the house."
?
Curious. My experience with Varta has been the polar (geddit?) opposite! I'm in Western Europe so perhaps the Varta batteries we get here are made somewhere else from the ones you get.
Duracell are still terrible here, though. I had a really powerful torch with an aluminium body which fell prey to leaks from Duracells and it very nearly destroyed the whole torch. Whatever that stuff that leaks is, it damn near welded the screw-on base to the barrel. I could only just get it free using a bench vice and a strap-wrench. IMO Duracells should come with diapers.
?
Thanks Jinxie,
?
I don't have any Vartas here in my recycle box but next time I'm at a store I'll check them out. I suspect they are made in China like just about everything else these days.
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Morris
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Re: Leaking alkaline cells
Sure, take some flour and throw a cloud of it and light a match and it will explode.? But it won't do that normally.
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On 9/7/2024 5:58 PM, Chuck Harris via groups.io wrote: A gander at youtube will find all sorts of daring do'ers that take
apart the AA cell lithium replacements for alkaline cells, unwrap the
lithium foil, and make them sizzle spit and spark, and catch fire.
Might be impossible in the can, but I see lots of impossible failures
regularly.
-Chuck Harris
On Sat, 7 Sep 2024 01:03:59 -0400 "Peter Gottlieb" <hpnpilot@...>
wrote:
In practice a small leak won¡¯t cause anything spectacular. The
solvent portion of the electrolyte will evaporate and some moisture
will get in and the cell will die. It would be hard to force enough
water inside to cause a significant energetic reaction. I know
because I get to do this at work as part of product DFMEA.
What does happen with a poor seal is reduced shelf life and that
would be a significant quality issue. The seals are pretty darn good
and a science all unto themselves.
Regarding charging lithium ion cell devices, yeah, don¡¯t do that on
couches or next to you in your bed.
Peter
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Re: Leaking alkaline cells
A gander at youtube will find all sorts of daring do'ers that take apart the AA cell lithium replacements for alkaline cells, unwrap the lithium foil, and make them sizzle spit and spark, and catch fire. Might be impossible in the can, but I see lots of impossible failures regularly. -Chuck Harris On Sat, 7 Sep 2024 01:03:59 -0400 "Peter Gottlieb" <hpnpilot@...> wrote: In practice a small leak won¡¯t cause anything spectacular. The
solvent portion of the electrolyte will evaporate and some moisture
will get in and the cell will die. It would be hard to force enough
water inside to cause a significant energetic reaction. I know
because I get to do this at work as part of product DFMEA.
What does happen with a poor seal is reduced shelf life and that
would be a significant quality issue. The seals are pretty darn good
and a science all unto themselves.
Regarding charging lithium ion cell devices, yeah, don¡¯t do that on
couches or next to you in your bed.
Peter
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Re: HP 8568B from hell to Heaven... a restoration story!
Maybe so,? but no thanks to FedEx.
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Re: HP 141T Power Supply Help Needed
Sorry, 38.6 x 0.707 = 27VAC.? 1/sqrt 2.
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-Frank
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Re: HP 141T Power Supply Help Needed
Mike,
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Wouldn't it be ~27VAC across the winding (11 and 13)? Or ~13.5VAC at both 11 and 12 and 13 and 12?? For a center tapped full wave rectifier Vout = Vp (sec)/2 - diode drop.? Since the center tap is -12.6V and you have 6.0VDC at the output, if we make -12.6V ground, you have Vout = 18.6VDC.? (18.6 + ~0.7)x2 = 38.6Vp.? 38.6 x square root 2 = 27VAC in rms across the winding from pins 11 to 13. Or am I missing something?
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-Frank?
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Re: HP 141T Power Supply Help Needed
Bill, ? 1.5V across R40 which is the bleeder resistor for the -12.6 bulk supply is definitely a problem.? There are only a few things that can cause that.? The next thing to do is check the voltage at the cathodes of CR1 and CR2.? If you don¡¯t have 24VDC there; check the AC voltage at the anodes of CR1 and CR2.? If the diodes check good then the wiring is open somewhere.? There only a few things left.? Lets hope that you have 24VAC at the terminals 11 to 12 and 12 to 13 on the power transformer.? If you don¡¯t have voltage at the power transformer you have a bad power transformer and those are almost impossible to find.? ? Best if luck, Mike ?
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From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Saturday, September 7, 2024 11:09 AM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Mike? Agree we've been through it all by now.? ?I did find a bad trace to the base of C11, I jumpered R45 straight over to it.??
Voltages overall changed slightly, biggest difference is i'm now sitting closer to -3v.? ? ? Across r40 I get 1.5v.?? At c6 I get -0.5v.?? 24v at diodes seems OK.?? Cr1 and 2 test OK.?
I've not had solid focus time this week, but before the weekend is up I will go through all the passive components again and make sure nothing changed behind my back.? Short of that, I'll start doing point to point continuity i suppose.? ?? Frank, I do have it isolated. And I have been replacing passives as I find?them.?? Maybe part of the issue.?? I'm thinking maybe diodes aren't appropriate..? ?? ? On Sat, Sep 7, 2024, 12:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: If you haven't already, you need to isolate the A1 and A2 boards from the rest of unit.? You're making this harder than it has be if you haven't already. Also, earlier you mentioned measuring R44 as 18k.? It is a 20k resistor with 1% tolerance.? That is 10% tolerance.? Most of the resistors on the A2 board are 1% tolerance.? It is well documented in the 140, 180 series mainframes that when these resistors go out of spec, they can bring the whole supply down. Make sure to reference the parts list of the manual.?? Pots and trim pots are also worth a close look on these units.? I've found faulty ones in these mainframes that cause funky symptoms.
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Re: HP 141T Power Supply Help Needed
Mike? Agree we've been through it all by now.? ?I did find a bad trace to the base of C11, I jumpered R45 straight over to it.??
Voltages overall changed slightly, biggest difference is i'm now sitting closer to -3v.? ? ?
Across r40 I get 1.5v.?? At c6 I get -0.5v.?? 24v at diodes seems OK.?? Cr1 and 2 test OK.?
I've not had solid focus time this week, but before the weekend is up I will go through all the passive components again and make sure nothing changed behind my back.? Short of that, I'll start doing point to point continuity i suppose.? ??
Frank, I do have it isolated. And I have been replacing passives as I find?them.?? Maybe part of the issue.?? I'm thinking maybe diodes aren't appropriate..? ??
On Sat, Sep 7, 2024, 12:45?AM Frank Mashockie via <fmashockie= [email protected]> wrote: Bill,
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If you haven't already, you need to isolate the A1 and A2 boards from the rest of unit.? You're making this harder than it has be if you haven't already.
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Also, earlier you mentioned measuring R44 as 18k.? It is a 20k resistor with 1% tolerance.? That is 10% tolerance.? Most of the resistors on the A2 board are 1% tolerance.? It is well documented in the 140, 180 series mainframes that when these resistors go out of spec, they can bring the whole supply down. Make sure to reference the parts list of the manual.??
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Pots and trim pots are also worth a close look on these units.? I've found faulty ones in these mainframes that cause funky symptoms.
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-Frank
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Re: Leaking alkaline cells
"Dead batteries given away free of charge."
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On 9/7/2024 7:14 AM, Michael Kellett via groups.io wrote: For a long time now I've used nothing but the industrial versions of Duracells. They used to be marketed as Industrial by Duracell and now as Procell.
I have no complaints. Just checked my store of new batteries, quite a range of sizes and ages -no leakers !
Checked the batteries in my Fluke 89IV DMM (4 x AA), hard to tell - the Procells in it might have been leaking but the terminals have been corroded a long time ago (its 25 years or more old) by some rubbish batteries. I changed the Procells any way.
My Fluke 84III is powered by an Industrial 9V which has a best before date of 2020. It isn't leaking but has some black goo on it from the decomposing black foam rubber installed by Fluke.
But I can offer a valuable research resource to the curious.
I used to buy coffee which came in large glass jars which were too nice to throw away. When I moved to my present location in SW Scotland more than 16 years ago it became harder to get rid of dead primary cells so I took to storing them in the coffee jars and somehow I've never got round to getting rid of them. So I have a collection of getting on for 500 dead batteries, mostly alkaline, mostly AA, many different makes and in various stages of decomposition.
If anyone would care to collect them from SW Scotland (for obvious reasons they can't be posted) and do the necessary sorting and analysis, I should be pleased to see the back of them.
MK
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Re: E4438c display problem, controler memory location please
If there is evidence of rodent infestation, I would start by thoroughly cleaning every circuit board with soap and water. It could be that vermin piss or crap is causing conduction to places it shouldn't be.?
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Frank Mashockie
Jinxie