Author Topic: Repair : Old Keithley 2000 teardown and fix  (Read 49125 times)

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Offline picburner

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #25 on: May 11, 2015, 05:36:55 am »
TiN, I measured my R153 (in circuit): both resistances are 3.60K.
 

Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #26 on: May 11, 2015, 02:47:16 pm »
Replaced vregs, R153 network, bodged zeners instead of 17V VR109 (don't have replacement yet),

Errors: 302.1, 302.2, 400.2, 401.2, 402.2, 403.2, 500.1, 500.2, 600.1, 600.2, 601.2
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Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #27 on: May 11, 2015, 04:17:50 pm »
Guess what... Part of problems come from gang switch. I removed it, and now can measure resistance and voltage if signal tied directly to input R115 and AGND (TP102).

302.1, 302.2 are also gone.

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Offline ManateeMafia

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #28 on: May 11, 2015, 04:24:45 pm »
Good find!  I just replaced the switch on my 2002 last week and I know it can be disassembled. Unfortunately, all the contacts will come out but it may be possible to clean it and reinstall.

The switches are pretty cheap and are probably worth ordering if you can get them. If you can't, I can get a spare out to you if needed. I ordered extra switches for 'future' issues.
 

Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #29 on: May 11, 2015, 04:34:26 pm »
Where do you order them?
I will take switch from my 2001 donor board, which i tear for parts. Switch can be disassembled by removing spring lock at front and pulling slider backwards all the way. Beware metal contacts, they will fly away as soon as free.

P.s. my RAID5 array at workstation gone sour, so I have it recovering on new 4TB drive, so had no chance to work on our noise comparison project yet. No data lost as first glance, but it takes time to get everything back. xDevs server is unaffected.
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Offline ManateeMafia

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #30 on: May 11, 2015, 05:03:17 pm »
I order my parts from Tektronix. I have building up a small collection of spare parts in addition to the repairs I have done.

Right now, the switches are on backorder. I have a couple spares on-hand but I ordered a couple extra due to at least one 2001 having a sticking switch. I had the switch fling apart on me, but this was after installing the new one. Can you tell what failed? Was it corrosion or some other problem. I think it is strange to use an open switch but I guess it works OK for the 8846A.

I am debugging the scripts now. Everytime I switch between the USB Prologix and the Ethernet version, something breaks. These all seem to be timing related and right now I am running the 2400 through its ranges. I can't imagine a pci based controller will have these weird issues.
 

Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #31 on: May 13, 2015, 02:43:38 pm »
I guess I spoke to soon for switches.. Removed one from donor board, disassembled to clean internal contacts, and now after assembly it does not lock in with usual click.
And messing with original switch - i somehow installed few contacts in wrong direction and now slider stuck inside, breaking everything.  |O Murphy gotcha me on these pesky switches.

So I'm in for couple, if you ordering.  ;)

UPDATE:

Assembled switch somewhat locked in front position for now, run selftest.

Errors: 400.2, 402.2.
Ohms 2W and 4W reading incorrect in middle ranges. 10Meg and higher is ok.

1VDC = K2001 : 0.999991, K2000 : 0.999948
2VDC = K2001 : 1.999976, K2000 : 1.99994
5VDC = K2001 : 4.999966, K2000 : 4.99999
10V = K2001 : 9.999905, K2000 : 9.99988
« Last Edit: May 13, 2015, 04:30:14 pm by TiN »
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Offline ManateeMafia

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #32 on: May 13, 2015, 06:05:15 pm »
I think I have two at home, and one or two on backorder.

If you want one or both, let me know. I will still be good with the backordered switches. I thought I was going to replace all of them, considering my Agilent meters that had worn contacts. Never hurts to have a backup plan.
 

Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #33 on: May 14, 2015, 01:08:27 am »
I'd get two from backorder extra, no need urgent, it would still take a while till I get everything else fixed properly.

Here are the bastards:


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Offline TopLoser

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #34 on: May 14, 2015, 01:02:38 pm »
Since we have gazillion of 2000 threads poping up every week, I'd think someone may be up for grabs on this one:
http://www.ebay.com/itm/Keithley-2000-multimeter-/161698789900?pt=LH_DefaultDomain_0&hash=item25a5ffba0c

All components seems there, just teared down. VFD likely be okay, getters are not white.
And price is okayish, if seller may accept reasonable offer :) I pass on this one, so who wants 2000 - that's ur chance :)

Seller accepted $95 shipped  :)

Arrived today, well packed and all complete. Meter in kit form! I connected all the big bits together and plugged it in - Error +514 displayed for a moment and then it seems to work just fine (only tested on DC volts so far though). Display is bright, case is in great condition, bench handle and feet all present and correct. Seems to be have manufactured 2005 so not too ancient.

Looks good so far, not bad for $95 shipped!!
 

Offline Smith

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #35 on: May 14, 2015, 01:59:51 pm »
Damn, cant really go wrong for that kind of money! I definetly payed more for my older unit (with a dim vfd).
Trying is the first step towards failure
 

Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #36 on: May 14, 2015, 02:35:19 pm »
Cool, photos or never happen  :P
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Offline TopLoser

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #37 on: May 14, 2015, 03:18:59 pm »
$95 shipped K2000 kit, almost no assembly required!

Appears to need a bit of calibration, just about functions as a 2.5 digit meter at the moment. Front/rear selector switch needs a bit of fiddly re-assembly (but all the bits are there), and the current measurement wire has been cut to get the front panel off (fuse, holder, spring all present though).

Nice and tidy, just need to find out how to make it read useful values now...
 

Offline TiNTopic starter

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #38 on: May 15, 2015, 04:23:08 am »
Poor current lead.. It is removable very easity from front panel, all is needed just push a spring and get it out.
Somebody was really desperate to take it out  :--

Noticed your board using caddock network, as well as Isabellenhutte current sense resistor.
Can you have more photos for PCBA, covering few parts. Also if you have different firmware - dump would be great to have for collection.

Thanks.
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Offline AudioplatinumService

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #39 on: May 15, 2015, 07:09:17 am »
Poor current lead.. It is removable very easity from front panel, all is needed just push a spring and get it out.
Somebody was really desperate to take it out  :--

Noticed your board using caddock network, as well as Isabellenhutte current sense resistor.
Can you have more photos for PCBA, covering few parts. Also if you have different firmware - dump would be great to have for collection.

Thanks.

Hi,
K2000 from Ian is sold to me, I can make dump and photos when arrive. I also have one K2015 with few problems and I have plan to solve and fix all problems on both DMMs.

Cheers,
Damir

Audioplatinum Service
www.audioplatinum.net
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Offline eas

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #40 on: May 15, 2015, 07:21:23 am »
Nice score on that box of meter parts. I thought it would be much worse off, seemed like a sketchy story that someone wouldn't be able to get it back together.  Not that it wouldn't have been worth the price it for the parts...
 

Offline Grapsus

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #41 on: May 15, 2015, 08:01:08 am »
How do you people get deals like this ? $95 for a Keithley 2000 is insane, I've never seen anything below $500, even for the trashed ones. Do you set up eBay alerts or something and then respond in less than a second to the seller ?
 

Offline sync

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #42 on: May 15, 2015, 11:26:10 am »
Maybe it depends on the country. I got my broken K2000 for 100€ at Ebay Germany. Working ones sold at 200-400€. There was even a working one for 130€ buy it now. Sadly I missed it.
 

Offline Smith

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #43 on: May 16, 2015, 07:27:00 am »
Its a combination of luck, search for the right parameters, and hope for cheap shipping.

Some will only ship with mayor and fast (expensive) shipping companies. This messes up a lot of mostly heavy equipment.

Bidding will mostly end up costly. Its more about the buy now or make a bid.

Sometimes they post the name/manufacturer wrong, or just dont know what they are selling. I have seen expensive gear been sold as "measurement stuff" even "I don't know what it is, just bid".
Trying is the first step towards failure
 

Offline eas

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #44 on: May 16, 2015, 09:50:39 pm »
In the US, I've been able to pick up 3 K2000 meters for $260, $335, and $365, including shipping.

The first I won in an auction, the second I picked up from an international seller because it came with a scanner card, which would probably have run $225 on its own. The third I got for the Buy-It-Now price within a couple of hours of it being listed. I was willing to pay more for it because it was running a recent firmware, which is required for support by Keithley's IVI drivers. The two I've received pass self-tets, seem in spec, as best as I can tell, and agree with each other within tolerances on the measurements I've checked. One has a nice bright screen, the other is dim. The remaining model was reported by the seller to fail two self-tests, which I know from research aren't critical, and could be cleared by blowing out the dust, or replacing an input FET. I'll see when it arrives.

In the same period, I lost two auctions for meters that ended up going for $250 and $305 + shipping, and another sold with an HP33120A that went for $453. I've probably been checking my saved searches once or twice a day. If I valued the time I spent looking for these deals on ebay at, oh, lets say $100/hour, then my prices per successful purchase would probably be $100-150 higher.

In the US at least, you should be able to get a decent meter for well under $500 if you are willing to spend some time looking and wait for a deal. $95 for a "kit" is insane though...

 

Offline eas

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #45 on: May 16, 2015, 10:24:43 pm »
Oh, its also worth looking the K2000s recently sold on ebay. You'll realize that you see lots of listings for units selling for $500/up because those don't sell very quickly, but there are a fair number of sales in the $200-350 range.
 

Offline Grapsus

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #46 on: May 17, 2015, 02:48:17 am »
You're right, past listings show pretty low prices. I'll have to check more often to strike one of those deals. I don't leave in the US but even with $60 shipping, $200 would be awesome.
 

Offline VintageNut

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #47 on: May 20, 2015, 06:31:53 pm »
I just received a 2000 that was built in 1997. A06 ROMs. Last calibration Oct 2007. Number of calibrations = 8. It appears that this unit was well taken care of the first 9 years of its life. I Paid $250 plus shipping.

Everything seems to work perfectly so far for DC volts, DC amps,  and ohms which is most of what I use a DMM for. I will check out frequency and temperature features later.

I do not seem to be able to include any attachments. Is there a post minimum to post a picture?
« Last Edit: May 20, 2015, 07:41:11 pm by VintageNut »
working instruments :Keithley 260,261,2750,7708, 2000 (calibrated), 2015, 236, 237, 238, 147, 220,  Rigol DG1032  PAR Model 128 Lock-In amplifier, Fluke 332A, Gen Res 4107 KVD, 4107D KVD, Fluke 731B X2 (calibrated), Fluke 5450A (calibrated)
 

Offline Grapsus

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #48 on: May 21, 2015, 01:27:44 am »
There is a Keitheley 2001 for parts that's gone for $200 tonight, it looked like a good deal. Sadly the shipping to France was $100.
 

Offline eas

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Re: Repair : Old Keithley 2000 teardown and fix
« Reply #49 on: May 21, 2015, 05:32:30 am »
There is a Keitheley 2001 for parts that's gone for $200 tonight, it looked like a good deal. Sadly the shipping to France was $100.

I was watching that one. Was going to bid in the 5 minutes between the end of an appointment and the end of the auction. Unfortunately, the appointment went 10 minutes long. Just as well. I have enough projects with two power designs bench power supplies I need to fix, another two coming that may need a fix, and three K2000s that I need to decide among before selling off one or two of them. I would have dropped out of the bidding at $175 probably.

Nice score, VintageNut. If you are planning on controlling it over RS-232 I'd suggest using a modified cable that leaves the RTS pin unconnected. For some reason the K2000 is wired to drive that pin, and versions of the firmware up to at least A15 seems to do so. Unfortunatley, the PC side correctly tries driving it in the opposite direction. The result seems to be that the inverter built into the level-shifter IC has trouble keeping up to the detriment of its ability to send data over the Rx pin. With the RTS pin connected, my ~1995 K2000 would stop sending data after less than 100 bytes. With the RTS disconnected, it was able to answer a *IDN? query every second for hours and hours without issue.
 


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