Author Topic: Restoration glory of Keithley 2001 DMM  (Read 206548 times)

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Offline TiN

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Re: Restoration glory of Keithley 2001 DMM
« Reply #575 on: July 01, 2016, 01:38:23 pm »
How much was for transformer. You got from official Tektronix support?
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Offline TomThaMan

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Re: Restoration glory of Keithley 2001 DMM
« Reply #576 on: July 01, 2016, 03:03:37 pm »
The transformer costs 320(!!) euro shipped. awful lot of money for a simple transformer. Its from Tek. If somebody got a good one for less I'm still happy to hear!
 

Offline TiN

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Re: Restoration glory of Keithley 2001 DMM
« Reply #577 on: July 01, 2016, 03:38:30 pm »
Yah, that's inline what I heard from others. Yikes. Been there before with HP 3458A transformer...  :rant:
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Offline girish

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Re: Restoration glory of Keithley 2001 DMM
« Reply #578 on: July 03, 2016, 06:03:13 am »
U320.6 is ADBUF+ node, common input of A/D buffer.
It's side of switch which routes 1.75V Reference voltage to ADBUF.
It shouldn't run to U510 which is switching in AC block.


So, I traced the ~1.8V (3 diode drop) 412.1 test signal according to the repair manual to pin 6 of U510 and it should show up on pin 7 through the switch. When my 412.1 test fails pin 7 is always at 0V.
 I cleaned with ISO again around the U5xx chips, re-soldered  U510 and the error went away for a whole day. I ran the automatic test for 24 hrs continuously and it kept passing. Its a little warm here today (room temperature is at 27.56 C and the air coming out of the DMM vent is around 50 C) and guess what the error is back. Wondering if U510 is faulty or some other part after that is pulling the switch output to low.

Excerpt from the repair manual


Test 412.1 – AC amps switch
Cannot measure 1.7V ±0.3V at A/D IN.
The 9.2mA ohms source is turned on to dump current through switch U323 (ACAL
pulled low) to the amps protection diodes (CR305 and CR309). The three diode voltage
drop is routed through U317 (/200uA pulled low), U320 (/ACA pulled low), U510
(REL3 pulled low), U526 and Q516 to the input buffer (Q512 and U520). The buffered
signal is tied to AMP IN.
The signal at AMP IN is then routed to the variable gain amplifier (VGA) and, being
positive, follows the non-inverting x1 path that consists of R530, Q509, Q507, U519,
R531, U509, Q501, and U516 to pin 12 of multiplexer U511.
The output (OUT) of the multiplexer is routed through buffer U342 to ACV/A. The signal
at ACV/A is routed through U320 (/AC pulled low) and applied to the A/D buffer
(U322), which is configured for x1 gain. Measure 1.7V at A/D IN.
« Last Edit: July 03, 2016, 06:05:18 am by girish »
 

Offline TiN

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Re: Restoration glory of Keithley 2001 DMM
« Reply #579 on: July 03, 2016, 06:21:13 am »
Try replacing LM339 which drive those switches. I had bad 339's in two out of 6 units before. Also could be your U510 is leaky/flaky.
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Offline girish

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Re: Restoration glory of Keithley 2001 DMM
« Reply #580 on: July 03, 2016, 07:12:07 am »
Try replacing LM339 which drive those switches. I had bad 339's in two out of 6 units before. Also could be your U510 is leaky/flaky.

Thanks!
Yes, I am about to order some DG211Y s, 411s, and 339s. Its definitely temperature related since the test passes at cold startup.

 

Offline pelule

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Re: Restoration glory of Keithley 2001 DMM
« Reply #581 on: July 03, 2016, 10:22:42 am »
If there is a temperature depending issue, you may search the critical part using coolant spray.
PeLuLe
You will learn something new every single day
 

Offline girish

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Re: Restoration glory of Keithley 2001 DMM
« Reply #582 on: July 09, 2016, 03:34:08 am »
Replaced U510(DG211Y) today. Self-test have been running for 4 hours and passing. I'll keep it running overnight, but looks like a flaky analog switch which was acting up at elevated temperatures was the issue here.
Thanks!
 

Offline girish

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Re: Restoration glory of Keithley 2001 DMM
« Reply #583 on: July 10, 2016, 01:10:00 am »
Automatic tests have been passing for 2 :(4+ hrs now. I think the unit is fixed. Now calibration $$$... :(
 

Offline Signal32

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Re: Restoration glory of Keithley 2001 DMM
« Reply #584 on: July 10, 2016, 06:59:42 am »
Now calibration $$$... :(
What have people been quoted for calibrating a 2001 ?
Also any recommendations for a quiet fan replacement ?
 

Offline Le_Bassiste

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Re: Restoration glory of Keithley 2001 DMM
« Reply #585 on: July 27, 2016, 07:04:06 pm »
for my KEI2001, it was (done by TEKTRONIX / KEITHLEY in Germering, Germany)
Cal & Adjust: 340 EUR
Cal Report: 70 EUR
Pick-up and Bring Sevice via UPS 50 EUR
so, that totals to 460 EUR plus 19% VAT = 547.40 EUR. (insert ring of cash register here).
cal docs consist of two reports: as-received and calibrated, with used assets listed.

for my KEI2002, they quoted cal & adjust 700 EUR (sans VAT)

 

Offline TiN

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Re: Restoration glory of Keithley 2001 DMM
« Reply #586 on: July 28, 2016, 04:27:41 am »
I'd suggest to keep same CFM/speed fan, to keep capacitor life. It also could affect calibration, as temperature condition is important with respect of all parts.
K2002's manual even state that unit need to keep same condition of rear scan-option opening as was during calibration (either covered or open).

Le_Bassiste

Congratz on your cal :) Is yours A08 firmware or B-series?.
Btw, that funny 20 uV range you saw on K2002 during power on, before trigger is not fake, it's lowest range meter can go with K1801 option. ;)
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Offline Le_Bassiste

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Re: Restoration glory of Keithley 2001 DMM
« Reply #587 on: July 28, 2016, 09:34:11 am »
it's actually this one   :-DD
so, it's an A08
 

Offline TiN

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Re: Restoration glory of Keithley 2001 DMM
« Reply #588 on: July 28, 2016, 11:17:45 am »
I was wondering where did the unit end up. Oh well, long live for meter. Would be interesting to know cal data, if you feel sharing.

I might find some testlogs of DCV and OHM tests of it, but that will need effort :(.
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Offline Le_Bassiste

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Re: Restoration glory of Keithley 2001 DMM
« Reply #589 on: July 28, 2016, 03:03:48 pm »
« Last Edit: July 28, 2016, 06:43:16 pm by Le_Bassiste »
 

Offline Jay_Diddy_B

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Re: Restoration glory of Keithley 2001 DMM
« Reply #590 on: August 03, 2016, 07:14:43 pm »
Hi,

I got a shipment of new parts from Keithley to complete my 2001 restoration. I bought my unit for $30.00 Canadian. I did the 're-cap and clean' and electrically it is 100%. Now it is time to fix up the outside. I got the meter so cheap I decided to buy new parts from Tektronix. It took about two weeks to get the parts.


New Handle


My unit was missing the handle



New Rubber Keypad

One of the range arrow keys was broken on mine.




Metal Case


The metal sleeve was missing.



Rear Bezel

This part was missing when I got the unit.



Total Cost around $250.00 delivered to my door.

Regards.

Jay_Diddy_B







 

Offline RobK_NL

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Re: Restoration glory of Keithley 2001 DMM
« Reply #591 on: August 03, 2016, 08:53:56 pm »
The transformer costs 320(!!) euro shipped. awful lot of money for a simple transformer. Its from Tek. If somebody got a good one for less I'm still happy to hear!
Only just saw this and jaw dropped. I paid 179 euro last year.
Tell us what problem you want to solve, not what solution you're having problems with
 

Offline Jay_Diddy_B

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Re: Restoration glory of Keithley 2001 DMM
« Reply #592 on: August 07, 2016, 03:11:11 am »
Hi,

I have to calibrate my Keithley 2001 post fix.

I have good equipment to perform the calibration including:

Fluke 732A
Datron 1281
Fluke 5101 which can be used as source, monitored by the Datron 1281
ESI 4W Resistance standard RS 925


So I am in pretty good shape.

The first step requires a 4 Wire short, using the Keithley 8610. I found this picture of the 8610:




And I have made this artwork:





Does anybody have an original 8610 or know what the other side of the board looks like?

I have read the Fluke white paper that says a low thermal mass is better.

Link: http://us.flukecal.com/literature/electrical-calibration/watch-out-those-thermoelectric-voltages-cal-lab-journal-reprint

Thanks !!

Jay_Diddy_B
 
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Offline saturnin

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Re: Restoration glory of Keithley 2001 DMM
« Reply #593 on: August 07, 2016, 11:26:31 am »
I bought 4-wire short from Fluke: 884X-Short (http://www.newark.com/fluke/884x-short/4-wire-short/dp/55M2652). It is nearly identical design to Keithley 8610. There is nothing particularly interesting on the other side :)

 
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Offline hugo

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Re: Restoration glory of Keithley 2001 DMM
« Reply #594 on: August 07, 2016, 11:59:23 am »
Quote
I bought my unit for $30.00 Canadian.

I thought the bottom price is 300 USD for an used and abused Keithley 2001 ... congrats to you :clap:
 

Offline TiN

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Re: Restoration glory of Keithley 2001 DMM
« Reply #595 on: August 07, 2016, 01:19:41 pm »
If one is patient, it's sometimes possible to get them for 100-200$ abused with missing parts.  :-DD

Seems it's a calibration week for everyone, don't mind if I join too? :)

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Offline Jay_Diddy_B

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Re: Restoration glory of Keithley 2001 DMM
« Reply #596 on: August 07, 2016, 09:38:42 pm »
I bought 4-wire short from Fluke: 884X-Short (http://www.newark.com/fluke/884x-short/4-wire-short/dp/55M2652). It is nearly identical design to Keithley 8610. There is nothing particularly interesting on the other side :)

Thank you for taking the time to post the pictures.

Regards,

Jay_Diddy_B
 

Online TheSteve

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Re: Restoration glory of Keithley 2001 DMM
« Reply #597 on: August 07, 2016, 09:53:38 pm »
If one is patient, it's sometimes possible to get them for 100-200$ abused with missing parts.  :-DD

Seems it's a calibration week for everyone, don't mind if I join too? :)

Seems you'll never really know what the real voltage is...    >:D >:D >:D
VE7FM
 

Offline Le_Bassiste

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Re: Restoration glory of Keithley 2001 DMM
« Reply #598 on: August 09, 2016, 01:11:33 pm »
but now you know that "42" was just part of the correct answer! :-DD
(to a voltnut, that is)
 

Offline lukier

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Re: Restoration glory of Keithley 2001 DMM
« Reply #599 on: September 10, 2016, 06:23:09 pm »
Hi,

recently I managed to grab 2001 for parts/repair really cheaply. It seems the unit had a long history, manufactured around 1992, A06 firmware, RevK analog board and RevJ digital. Someone already replaced most of the caps on the analog board around 2004/2007 (these were the dates on the caps). I replaced some of them anyway and replaced all on the digital board (these were original and leaking a bit). All the power rails seem OK.

However, my problem is with the ADC board. It is also unusual - it seems Keithley didn't have 7.68 MHz oscillator, so they developed a 2001-132-02A mini board with XTAL, HCU04 & misc to generate the clock. It was failing all the 200.x tests and in consequence some other tests as well.

I've checked the front end switches and muxes and these seemed to work ok, providing on AD_IN 0V, 7V, 10V or 1.75V*5 in various diagnostic modes. Then I noticed that R857 (sits between -15V and NE5534) is damaged, it got burned pretty badly, leaving tar on the PCB and came off the PCB in two parts. I replaced that with a new 100 Ohms and hoped that was the problem, but unfortunately no :( I did some more probing, checked Q806 (as this was the issue for ManateeMafia) etc, and then I must have slipped the probe perhaps (I don't see any other explanation), because the Altera CPLD no longer works. It receives clock and data on SCLK/DATA_IN but DATA_OUT remains silent. Now built-in tests hang on 200.x.

I know it's a long shot, but maybe one of the forum members has a spare 2001 ADC board they could part with (for a reasonable price)?
 


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