Keithley 193 schematics - Page 1
Forum section: electronics / repair

author: Sigma9876
author_rank: Newbie
timestamp: January 13, 2024, 07:18:36 am
content: Hi everyone,scored a Keithley 193 DMM lately - great instrument and in good shape.However, for some minor things (check caps etc) I would need the schematics. The problem is that all the manual versions out there (including the original one at the Tek website) have diagram pages which are barely readable due to a very poor scan quality.So: Does anyone own a printed (or better scanned) version and would be so kind to provide it? As said, it's just about the 3-4 pages with the schematics. Any format appreciated - I would happily puzzle together some phone camera fotos.Many thanks in advanceSigma9876

author: coromonadalix
author_rank: Super Contributor
timestamp: January 13, 2024, 03:30:33 pm
content: some roms here etc ... teardownhttps://www.eevblog.com/forum/testgear/brief-teardown-keithley-193-system-dmm/on Ebay you have some sellers, ask them if they can confirm the schematic readable and clean ... not made with "all you can find on the web"not sure if the 194 is a brother ?? some schematics are less crappy

author: Kleinstein
author_rank: Super Contributor
timestamp: January 13, 2024, 04:32:01 pm
content: The schematics I got (likely from DevX) is not that bad. Every 2nd page is a bit thin, but still readable. The resistor values are litsted in an extra table if needed. I would consider the scan good enough, though not perfect.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 13, 2024, 10:06:55 pm
content: yeah seen them, but i dont know why they are so crappy, have they been fuzzed out / garbled this way ?? when the other manual parts / pages are fine ?

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 04:50:59 am
content: yeah thanks: seen that and read in detail. Very helpful at least for comparison with my unit; however no info/links regarding better readable schematics.sigma9876

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 04:52:02 am
content: ...ah sorry: I will check the 194 info. tx,

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 04:56:52 am
content: @Kleinstein:Well yeah, on mine even the rectangles showing the ICs are pixelated. Neither part# nor values readable (sometimes you can guess...)Maybe yours is better - could you show it?

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 05:01:03 am
content: @coromonadalix:My guess is that the rest of the manual has been PDFed from a text file, whereas the schematics are on larger fold-in pages in the original printed version. Thus they have been treated (=scanned) separately and much worse.

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 05:36:28 am
content: @coromonadalix:Had a quick overview on the TEK website:191 5.5 classic rhomb192 6.5 shoebox193 6.5 system194 4.5 system195 5.5 shoebox196 5.5 shoebox197 5.5 classic rhomb198 -199 5.75 shoeboxThe closest brother of the 193 is thus the 192. The schematics are similar, but different still. In the manual they are much better readable, so they might be helpful. Tx for the hint.

author: Chris56000
author_rank: Frequent Contributor
timestamp: January 14, 2024, 05:07:08 pm
content: Hi!The '192 and '193 aren't close enough for the 192 book to be a reliable guide, as the 193 uses 14–segment display devices – I am studying the 193 circuits from what is freely available online to see shat I can decipher, but new drawings won't be a quick or easy job I'm afraid!Chris Williams

author: Kleinstein
author_rank: Super Contributor
timestamp: January 14, 2024, 05:59:35 pm
content: I don't don't see such a major issue with the quality of the manual. Essentially all is still readable.I woul consider the K196 the closest relative (at least for the ADC part), but no real need to use it to help with the schematics.Attached is a portion of the schematics that looks about worst, and there is one more area (~ 1/4 page) similar bad. One can still get a good guess there.P.S: I found one more bad page with the power supply - there things are really hard to read. The version I have a copy is from 1/23/2001 and 8.7 MB large.

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 06:47:41 pm
content: @Kleinstein:You are right - the 196 is pretty similar (as for the ADC).Concerning the readability: most (exception below) you can put together using the parts list - you're right with this.However the Fig 7.5 (Digital board) in unreadable at the bottom (at least in my version) - see attached PDF. If you have anything better than that, I would appreciate getting a copy.Sigma9876

author: Sigma9876
author_rank: Newbie
timestamp: January 14, 2024, 07:06:45 pm
content: @Chris5600:100% ack. What is on the web are bad scans - I just thought maybe someone has the paper book and is not asking 40$ for 3 pages.The 192 / 193 are different (like you say) as for the display, so you cannot take over the digital circuits as such.Sigma9876