Products > Test Equipment
Keithley 197A owners' corner
tooki:
--- Quote from: Zachrey on June 09, 2020, 12:27:32 am ---Please help!
I just got a Keithley 197A from a seller on eBay.com and it is clearly defective! The seller will not take a return so I may have to try and fix this bugger! I have a little bit of experience with this and only have an oscilloscope and a multimeter to work with. Here is a Youtube video of what the unit is doing. Do you think there is any hope?
https://youtu.be/6OrLtb9O-co
Thanks!
Zac
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Do not cross-post. As I said in the other thread, with a new question, you should be starting a new thread anyway.
Brian of Romsey:
--- Quote from: rastro on July 23, 2019, 01:08:25 am ---
... Stuff Elided ...
Another solution I thought about is making a PCB that replaces the current display board (same size) but has SMD LEDs replacing the LCD along with a plastic template/screen for symbols/words. Getting the double sided (?) PCB produced in small quantities would be reasonable. However soldering all those SMD LEDs would be certainly be a labor of love.
... More Stuff Elided ...
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With the likes JLCPCB now offering SMD assembly this may well now be a possibility. See for the sort of thing they are able to deliver. Contrary to normal thinking, one would look to make a design with the smallest possible LED that would be impossible to hand solder just to get the best display. This also opens up the possibility of using colour creatively; red for the minus sign, blue for AC, white for the digits, blue for resistance symbols, green for voltage symbols, yellow for current symbols, etc. The units part on the right could even be done with a small RGB TFT or an OLED. One could even argue that AUTO, REL, dB, STO, & RCL could move to the left side given that it would become free-form rather than 1 of N. LED Bar graph along the bottom anyone?
Cheers, Brian (trapped in lock-down on the wrong side of the world).
MathWizard:
I saw the backlight/film-strip mod for these, I hope to buy some of it soon and try it.
Right now, my k197 reads 10V as 14V , I'm getting used to the front end and how it works. This is fun but frustrating too. But I should be close
cnt:
I just picked up one of these for almost nothing with the power cord cut off (non-A) its cal stickers were intact though so I don't think anyone has attempted to repair it (if its broken at all).
Before I dig in too much I just wanted to know a few things:
1) Whats up with the mains fuse. it looks like it has a carbon resistor inside of it.
2) ~~~Will this thing operate without its IEEE board installed? I don't want to bother pulling that card on and off to test.~~~ Edit: It will. I bodged up some mains wiring while i figure out the best repair for the cord, and it works fine without that board.
This (photo) is what I found inside when opening it. It looks like the battery was disabled during the last cal (2004) the chips are dated 1987 so I assume during calibration the battery was dead so they just disabled it.
cnt:
Hi again 197 owners. hopefully someone is monitoring this thread. I've got mine repaired mostly but the gpib chips are quite warm. Warm enough that the 7805 and chips are making the top case near the back a little warm. Is this normal?
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