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All my TM (usually) works very well. My ongoing projects are vintage Keithley. I have not found a Keithley forum. Do many here delve into the brown boxes?
Jeff
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<Raises hand>
I do. I am working on a 263 at the moment. The best source for discussion I have found is the EEVBlog forum.
Shaun M
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<+1>
I love Keithley's and repaired quite a bit of them, mostly DC/LF stuff.
Actually have 263 on bench too for some repairs. :)
BR,
Illya
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On 05/04/2024 1:33 AM, Shaun M via groups.io wrote: <Raises hand>
I do. I am working on a 263 at the moment. The best source for discussion I have found is the EEVBlog forum.
Shaun M
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On Sat, 4 May 2024, Ilya Tsemenko wrote: It's interesting -- I also have 263 waiting in queue for refurbishment and calibration as well as several 237 and 238 SMUs and couple of 6517A units :) Almost done with my HP/Agilent boat anchors, waiting for the last 4 to return from Keysight calibration, then will take on bunch of Keithleys. Which are Tektronix now, BTW, so they all probably belong here now. <+1>
I love Keithley's and repaired quite a bit of them, mostly DC/LF stuff.
Actually have 263 on bench too for some repairs. :)
BR,
Illya
On 05/04/2024 1:33 AM, Shaun M via groups.io wrote:
<Raises hand>
I do. I am working on a 263 at the moment. The best source for discussion I have found is the EEVBlog forum.
Shaun M
--- * * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * *
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I have a 179 as my shop DMM. It is the only instrument I own which goes to the cal lab.
--
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
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I've got a Keithley 2015THD DMM, and I also have a basic Keithley 2000 DMM. I've also got one of the Keithley 2200 programmable power supplies plus another 2200 that needs to be repaired.
I usually operate all of these remotely via GPIB although the 2200 also supports USB.
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I have some Keithley too: some 7001 fresh refurbished by me and waiting for any hand-made board :) And Keithley 230 (not sure regarding working). I switched it on about a 15 years ago. Peter сб, 4 мая 2024?г. в 16:24, jmr via groups.io <jmrhzu= [email protected]>:
I've got a Keithley 2015THD DMM, and I also have a basic Keithley 2000
DMM. I've also got one of the Keithley 2200 programmable power supplies
plus another 2200 that needs to be repaired.
I usually operate all of these remotely via GPIB although the 2200 also
supports USB.
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I have a 179 bench DMM also. I usually leave it running because I'm always using it to check this and that. I also have a 147 Nanovolt Null Detector. After I capacitor-discharge welded all the crimp connections, it works well AFAICT but I don't have the cable and it turns out I'm not enough of a volt-nut to make proper use of it. I'd rather have a 155 or an HP 419 or a Fluke 845. Dave Wise ________________________________ From: [email protected] < [email protected]> on behalf of jmr via groups.io <jmrhzu@...> Sent: Saturday, May 4, 2024 6:24 AM To: [email protected] < [email protected]> Subject: Re: [TekScopes] Keithley anyone? I've got a Keithley 2015THD DMM, and I also have a basic Keithley 2000 DMM. I've also got one of the Keithley 2200 programmable power supplies plus another 2200 that needs to be repaired. I usually operate all of these remotely via GPIB although the 2200 also supports USB.
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I've got a older 155 analog voltmeter. My favorite analog bench voltmeter. 1 microvolt to 1000 volt full scale, zero center, battery powered. Unfortunately, one of the chopper fets in the input circuitry died and I have no idea what they are. I keep my eyes open for another unit for sale.... On Sat, May 4, 2024 at 9:20?AM Dave Wise via groups.io <d44617665= [email protected]> wrote: I have a 179 bench DMM also. I usually leave it running because I'm
always using it to check this and that.
I also have a 147 Nanovolt Null Detector. After I capacitor-discharge
welded all the crimp connections, it works well AFAICT but I don't have the
cable and it turns out I'm not enough of a volt-nut to make proper use of
it. I'd rather have a 155 or an HP 419 or a Fluke 845.
Dave Wise
________________________________
From: [email protected] <[email protected]> on behalf of jmr via
groups.io <jmrhzu@...>
Sent: Saturday, May 4, 2024 6:24 AM
To: [email protected] <[email protected]>
Subject: Re: [TekScopes] Keithley anyone?
I've got a Keithley 2015THD DMM, and I also have a basic Keithley 2000
DMM. I've also got one of the Keithley 2200 programmable power supplies
plus another 2200 that needs to be repaired.
I usually operate all of these remotely via GPIB although the 2200 also
supports USB.
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I'm assuming the failed FET is in a metal can, if so the failure could be tin whiskers. Several cures have been discussed in TekScopes recently. The simplest was to rap the can to mechanically dislodge the offending whisker. More in the last resort category was finding a short and fusing it with a voltage low enough to not damage the semi when the short disappears. 1st step is to ohm out the device to see if there is a short. Good luck.
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Hi I have a 164 with some sexy nixies, I replaced something to get it working I cap if I recall correctly. I just decided to order the manual for it, I love the original manuals if I can find them. I do this as a hobby so I need all the help I can get.
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On Sat, May 4, 2024 at 11:13 AM, Bruce Atwood wrote: More in the last resort category was finding a short and fusing it with a voltage low enough to not damage the semi when the short disappears. I've done this with a bunch of PNP Ge transistors that had developed internal shorts from tin whiskers. I used a AA battery to drive current thru the whisker and "fuse" it. To do this, you MUST apply the voltage so that it won't flow thru the PN junction once the whisker is gone. This works, but the whisker may grow back. I had about 20 Ge transistors to work with, and some of them had to be treated 2-3 times before the repair seemed to be "permanent," where "permanent" was about a week. In the end, I tried replacing all the PNP Ge transistors with 2N3906s, and that worked perfectly. This was in a bunch of Tek 3S76 plugins. OTOH, I'm not sure there were ever any FETs in those tin whisker prone cans. -- Jim Adney Madison, WI USA
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I use a 196 regularly and it's my bench standard when doing calibrations on other gear. It the only one that gets a professional cal annually.
Rich
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Hi,
I also have a few Keithley instruments :
- one 480 Picoammeter, works great
- One 616 digital electrometer which was "flaky" when I got it. I have since replaced the dual FET (Q301 A/B) in the Autoranging Amplifier. I also installed a standard BNC with an isolated mount to replace the input Triax connector, which was missing when I bought the unit.
I replaced the op-amp on the input board with an LM308. The original chip was the source of low-level AC oscillations, which resulted in unstable readings.
I also designed a small board with a 68HC11 which plugs into the QA408 socket, which normally carries the LSI-2 chip on the logic board. This was done as a protection against a potential failure of the original SL35155 chip, which is pure unobtainum.
Now the 616 is future-proof and it works great !
I even sold a few of these replacements boards for the SL35155 on a popular auction site. If anyone is interested, just drop me a PM.
- I also have a 261 Picoampere source, which was the cause of countless headaches because of erratic drift. At first I thought it just needed to be calibrated, but weekly recalibration is not what you expect to do ! Finally, I found that the 200-ohm calibration potentiometers were prone to random changes in cursor resistance, and since cursor current is several milliamps, this resulted in degraded accuracy. I couldn't find any replacements for the pots, and concluded that the design of the power regulator with these potentiometers was inherently flawed. One day I decided to bite the bullet and I designed a new regulator board, using good cermet trimpots in a scheme where the cursor current is close to zero. This performed exactly as expected, and I have not seen any significant drift in output current ever since.
If anyone is interested in the new regulator design, I have schematics and a few blank PCBs available.
That's all !
Cheers,
Joel
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I have 610B; we used those to measure the triboelectric charges on toner way back when laser printers were in vogue.
I am surprised to find that there is no Keithley groups.io group.
DaveD
KC0WJN
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On May 5, 2024, at 08:34, Joel Setton via groups.io <setton@...> wrote:
?Hi,
I also have a few Keithley instruments :
- one 480 Picoammeter, works great
- One 616 digital electrometer which was "flaky" when I got it. I have since replaced the dual FET (Q301 A/B) in the Autoranging Amplifier. I also installed a standard BNC with an isolated mount to replace the input Triax connector, which was missing when I bought the unit.
I replaced the op-amp on the input board with an LM308. The original chip was the source of low-level AC oscillations, which resulted in unstable readings.
I also designed a small board with a 68HC11 which plugs into the QA408 socket, which normally carries the LSI-2 chip on the logic board. This was done as a protection against a potential failure of the original SL35155 chip, which is pure unobtainum.
Now the 616 is future-proof and it works great !
I even sold a few of these replacements boards for the SL35155 on a popular auction site. If anyone is interested, just drop me a PM.
- I also have a 261 Picoampere source, which was the cause of countless headaches because of erratic drift. At first I thought it just needed to be calibrated, but weekly recalibration is not what you expect to do ! Finally, I found that the 200-ohm calibration potentiometers were prone to random changes in cursor resistance, and since cursor current is several milliamps, this resulted in degraded accuracy. I couldn't find any replacements for the pots, and concluded that the design of the power regulator with these potentiometers was inherently flawed. One day I decided to bite the bullet and I designed a new regulator board, using good cermet trimpots in a scheme where the cursor current is close to zero. This performed exactly as expected, and I have not seen any significant drift in output current ever since.
If anyone is interested in the new regulator design, I have schematics and a few blank PCBs available.
That's all !
Cheers,
Joel
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Yes, I'm surprised about the lack of traffic on forums and YT about the old keithleys. I have working 2000 dmm, 236, and 610C units. I am getting into the fix with a 619. I was lucky to get a printed manual for the 619. I intend to have another go with my 228 after further honing of my chops.
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It took me a very long time to find an original manual and probe for my 610B electrometer.
I was thinking of starting a Keithley group but it's hard to gauge how much interest there would be.
DaveD
KC0WJN
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On May 5, 2024, at 18:51, jspencerg via groups.io <jspencerg@...> wrote:
?Yes, I'm surprised about the lack of traffic on forums and YT about the old keithleys. I have working 2000 dmm, 236, and 610C units. I am getting into the fix with a 619. I was lucky to get a printed manual for the 619. I intend to have another go with my 228 after further honing of my chops.
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I know what I'd like: to glom onto this forum and the Tekwiki with all the Keithley stuff. A weak argument to do this would point out that:
1. Tek now owns Keithley
2. The two companies have shared kin since 1990 with the DM5120 having some Keithley 196 innards.
:-)
Reading a Keithley manual is so much like reading a Tektronix manual. Both having high quality and same organization.
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Yeah have a number of Keithley items (a couple 181, a couple 192, a few 197, a 228A, a 196, 150, 131, 130, 128), nothing current only working older pieces in my meter collection, and still have a 2000 that I havent fully refurbished. Have been looking for a 263 for a while.
Also a little surprised that there isnt a Keithey specific forum.
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Hi,
I'm looking for a Keithley 2000 motherboard.
Mine has some broken PCB tracks but I can't fix it.
The PCB is multilayer.
Thanks if anyone can help me.
Mauirzio
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Shaun M
Sergey Kubushyn
Dale H. Cook
Rey
Richard Peterson
Nik Milosevic
maurit