Electronics > Repair

Keithley 2001 butchery and cosmetic repair help

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Finnaaah:
Hi everyone
I recently picked up a Keithley 2001 for a shockingly good price from someone who imported it from a used equipment seller in China. That is to say, without any way of getting background info. The unit came with fresh calibration from the seller but started throwing up errors and misbehaving, which is when it got passed on to me. It does actually work here and there, and when it does it seems to agree with my other meters on all measurements, but it's very hit or miss getting it there :scared: I'm enjoying the process of fixing it, and have included a link to some pictures of the condition it landed in (I think it's an ex e-waste unit) :popcorn:

https://imgur.com/a/RpYCIZQ

I wanted to ask others for ideas on fixing the front panel up. I'm going to restore it's color following TiN's awesome article in which he used hydrogen peroxide and sun. It's pretty yellowed so I'll be using a culturing cabinet at my work to give it direct UV as evenly as possible. The other issue with the front panel is the buttons. The left half work perfectly, but the right half require a fair bit of force in order to register which is a pain when navigating through the menu. Would anyone happen to have a spare membrane sheet of the buttons they're willing to sell (or even better, a front panel)? I've found one seller online but they're asking $330 + shipping for just buttons :palm: Otherwise, does building up the carbon patch on the buttons sound like a somewhat sane idea?. The last (slightly mundane) issue related to the front panel was the silkscreen for the power button. Would anyone have experience with touching up faded silkscreen on plastic?

Thanks for any suggestions, and sorry these questions aren't super electronics related :-/O


Laval:
Congratulation on the meter, it's a great unit.

On the 4th picture from the top, there is quite a bit of flux residue. This should be cleaned. If there are other messy spots like that, they should be cleaned as well. Of course, look closely for bad solder joints and bad contact with connectors. A usual problem with these units is the electrolytic capacitors. They tend to leak and cause all sort of issues with other components and the boards. Some people say they had a bad batch of capacitor at the time even from reputable manufacturer. A complete recap is probably in order then see if the problem is still present.

As for the front panel, something that worked very well for my 2001 and my 2015 is bleach. This video shows a method that worked for me at least.



12% (40 vol) peroxide cream works well because it sticks to the surface. You can then wrap it in saran wrap and let it outside exposed to the sun for a few days. It will not become completely white, this is not its original color, but the yellowing should mostly disappear.

https://xdevs.com/ is a remarkable site that contains a wealth of knowledge and data on these devices, I suggest you take a look if you have not already done so.

Be cautious when working on these boards, make sure you use an ESD wrist strap and don't touch the components too much if you don't have to.

Zucca:
First thing to do is to replace all the electrolytic caps... and check if they leaked already or not.
Do not assume if they look good there is no problem...

Also two caps (should be mentioned in the xdev) need higher voltage rating....

Overspeed:

--- Quote from: Zucca on May 22, 2024, 05:54:16 pm ---First thing to do is to replace all the electrolytic caps... and check if they leaked already or not.
Do not assume if they look good there is no problem...

Also two caps (should be mentioned in the xdev) need higher voltage rating....

--- End quote ---

Hello

the link for the 2000 cap problem

Question : Also two caps (should be mentioned in the xdev) need higher voltage rating....
can you put more information / link thanks

https://www.eevblog.com/forum/testgear/keithley-2000-and-the-leaking-caps

Regards
OS

Finnaaah:

--- Quote from: Laval on May 22, 2024, 05:41:15 pm ---Congratulation on the meter, it's a great unit.

On the 4th picture from the top, there is quite a bit of flux residue. This should be cleaned. If there are other messy spots like that, they should be cleaned as well. Of course, look closely for bad solder joints and bad contact with connectors. A usual problem with these units is the electrolytic capacitors. They tend to leak and cause all sort of issues with other components and the boards. Some people say they had a bad batch of capacitor at the time even from reputable manufacturer. A complete recap is probably in order then see if the problem is still present.

As for the front panel, something that worked very well for my 2001 and my 2015 is bleach. This video shows a method that worked for me at least.



12% (40 vol) peroxide cream works well because it sticks to the surface. You can then wrap it in saran wrap and let it outside exposed to the sun for a few days. It will not become completely white, this is not its original color, but the yellowing should mostly disappear.

https://xdevs.com/ is a remarkable site that contains a wealth of knowledge and data on these devices, I suggest you take a look if you have not already done so.

Be cautious when working on these boards, make sure you use an ESD wrist strap and don't touch the components too much if you don't have to.

--- End quote ---

I have no idea how the last owner managed to get so much flux under there, I've just desoldered it and cleaned that up (bye bye calibration) along with all the other flux I could find. I believe that could be what caused some of the errors which could be explained by small leakage currents, there was lots of flux and grime on the A/D board. Looks like whatever solder was used was pretty terrible quality, the flux has eaten off some of the solder mask and the smell was unbearable :rant: Thanks for the video on the whitening process, there's some useful info in there. I'll order some of the cream and maybe try find a liquid oxi booster, the result in that video looks pretty amazing :) In TiN's/xDevs article, he mentioned some of the text on the screen was damaged in the process. Did you tape up the screen, or find that it wasn't an issue? I'm worried that the text will just peel off considering it's age :scared:


--- Quote from: Zucca on May 22, 2024, 05:54:16 pm ---First thing to do is to replace all the electrolytic caps... and check if they leaked already or not.
Do not assume if they look good there is no problem...

Also two caps (should be mentioned in the xdev) need higher voltage rating....

--- End quote ---

Fresh caps just arrived, I desoldered all the original caps first thing and luckily no leaking at all. I was surprised considering their date-codes and the absolute havoc I've seen them wreak on others boards :-//

Will post some photos of the retrobrighting after it's finished  :-+

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