Keithley 177 calibration plate missing - Page 1
Forum section: electronics / repair

author: tron9000
author_rank: Frequent Contributor
timestamp: August 01, 2017, 12:17:35 pm
content: Didn't know whether to put this in the Wanted/For sale section or repair - so apologies if I got it wrong.I scored this keithley 177 in a dumpster dive! I has the usual issue of the range switches needing a clean, so when I took the top off I found that someone else must have had a go as the calibration plate was missing.Given that this thing has an asset number date '79, I think i will need a quick check, so does anyone have a decent image of the plate or even a replacement plate they can spare?Cheers

author: macboy
author_rank: Super Contributor
timestamp: August 01, 2017, 02:47:24 pm
content: It's actually an electrostatic shield. The fact that it has holes to access the trimmers and instructions/labels for them is just for convenience of adjustment. When I searched google images for "Keithley 177", literally the second image in the result is what you are asking for.

author: tron9000
author_rank: Frequent Contributor
timestamp: August 01, 2017, 03:20:49 pm
content: so its not an EM shield? right you are then! I was hoping to find a top down image of it (or scan) so I could cut my own out, but if its going to make no difference to performance, then I'll leave it off.

author: carl_lab
author_rank: Frequent Contributor
timestamp: August 01, 2017, 06:33:11 pm
content: Maybe this could help you:

author: tron9000
author_rank: Frequent Contributor
timestamp: August 02, 2017, 07:53:37 am
content: Thanks Carl_lab I found that one not long after. I think it'll do for now to calibrate it, but it would be nice if someone had scanned it. If i find another, I will do it.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 02, 2017, 11:46:44 am
content: Hello,I have one, but I didnt tear it down for ages altough I must one day as the GPIB card is acting up.IMHO; the main role of this metal plate is to act as a "seat" for the GPIB option or the battery pack.Tam

author: tron9000
author_rank: Frequent Contributor
timestamp: August 02, 2017, 11:48:53 am
content: Quote from: TAMHAN on August 02, 2017, 11:46:44 amits has GPIB expansion? is that what the empty DIP socket is for?

author: macboy
author_rank: Super Contributor
timestamp: August 02, 2017, 12:03:11 pm
content: Quote from: TAMHAN on August 02, 2017, 11:46:44 amIt is definitely a shield and I'd recommend keeping it in place during operation to reduce noise and interference. That's why the adjustment trimmers are accessible through it.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 02, 2017, 02:09:03 pm
content: @tron yes. Either that or battery. The DIP is for the interconnect cable. Sadly I dont have the time to tear mine apart for now.@macboy ofc, I got mine in place.P.S. I got the service manual for the whole GPIB crappe. If you want I can photograph it in.Tam

author: tron9000
author_rank: Frequent Contributor
timestamp: August 02, 2017, 02:17:53 pm
content: @ TAMHAN - could be usefulSome digging...Quote...From 177 service manualand sure enough from the 1793 manual:

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 02, 2017, 03:15:17 pm
content: Tron, what you miss is the schematics. Fuck this shit:http://www.tamoggemon.com/test/2017/K177GPIB.zipI dont have a PEROM reader. If you do have one and are close to Austria, come to my office, tear the unit down and grab the PEROMs if you want to clone the unit or shit.

author: tron9000
author_rank: Frequent Contributor
timestamp: August 02, 2017, 03:20:17 pm
content: thanks for the offer but I don't think I'm going to be in Austria for a while!But there's enough info there for a possible hack maybe? IEEE-488 to USB? Thanks anyway.

author: alm
author_rank: Super Contributor
timestamp: August 03, 2017, 12:04:25 am
content: Quote from: TAMHAN on August 02, 2017, 03:15:17 pmDo you mind uploading it toTiN's siteandKO4BBor do you mind me doing that?

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 03, 2017, 12:18:15 pm
content: alm, I uploaded to Tin some time ago pics of an Unigor 6e but he didnt do dick with them.So feel free to upload whereever you want, even though I would love to stamp the pics before with my instagram account. So hit me up at tamhan@tamoggemon.com, also as I have some more.Tam

author: alm
author_rank: Super Contributor
timestamp: August 03, 2017, 01:17:42 pm
content: KO4BB has already added a service manual I uploaded a week or so ago. I can't speak for TiN, but I assume he will get around to it eventually. It does not hurt to have information in two places in case one of them ever goes down.I've sent you an e-mail. You may want to edit your message so spambots do not get your e-mail address (assuming your e-mail address is not on every spam list yet).