Short repair Keithley 2000 ERR500.2 - Page 1
Forum section: electronics / repair

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 07, 2017, 09:40:44 pm
content: Hoylast year, im lucky to get one nice 96'sK2000for massive under 300€ from the bay here in germany. I'm quite happy with it.By the way,still to rely on it, i bought a brand new 34461a, lookin now to some expensive Vishay's plus something like xDevs's KX Voltage reference. What do you call this? Addict for what?OK, the most things icanwill do, i want to make it by myself, still in hope to learn something...Now, the K2000 is ok, butit couldn't measure 4W. Selftest are all ok, but withERR-500.2(4W SENSE).After studying Repair-Manual and this outstanding assistance extern schematics (big, big thanks to the person who made this reverse engineering), i realized, thatSense-HI is permanently at +15V.Some measurements show, that there is a little black dot, a JFet-Transistor (Q107), that don't ask me to give the 15V to Sense-Hi.After 20 years, i have punished him, to go out of my DMM, and lo and behold, my DMM is doing his job also with 4W, the error is gone. Although not replaced with another one for now, till i have one.My question for now:is this JFET like a fuse, for stupid people like me (but don't do it), they stick the big power in this little sense-bindingpost?(Edit: don't think it the wrong way...)is it like a pullup?Maybe, it could be a nice theme for Dave, to explain this excellent range- and error-switching concepts along with this dmm?Thanks to all,H.-W.Edit: orthography

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 07, 2017, 10:00:40 pm
content: The Art of DMM

author: onesixright
author_rank: Frequent Contributor
timestamp: February 07, 2017, 10:12:33 pm
content: nice pics!lens ? aperture?

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 07, 2017, 10:43:18 pm
content: Quote from: onesixright on February 07, 2017, 10:12:33 pmFUJIFILMX100S23.0mm Solid Lens 1:2.0mostly ƒ/5.6 0.0080s(1/125)I had several APS-C Mirror-Reflex-Camerasbut this is comparatively so outstanding and compact, that i sold nearly all my other gear.

author: onesixright
author_rank: Frequent Contributor
timestamp: February 07, 2017, 10:56:52 pm
content: Quote from: hwj-d on February 07, 2017, 10:43:18 pmThanks!I love the low "level" shots (can be lower) , maybe close it down 1-2 stops (for a tad more DOF)?PCB's makes a nice subject

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 07, 2017, 11:21:06 pm
content: Quote from: onesixright on February 07, 2017, 10:56:52 pmSometimes they are really sexy, like "sex-on-a-stick ..."

author: z01z
author_rank: Regular Contributor
timestamp: February 08, 2017, 09:44:25 am
content: Quote from: hwj-d on February 07, 2017, 09:40:44 pmSorry to go off-topic.It acts a low leakage diode.Have a look at thisbook.There's also a TIappnote.

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 08, 2017, 10:29:27 am
content: Quote from: z01z on February 08, 2017, 09:44:25 amYou bring it back.QuoteMany thanks for this info!

author: TiN
author_rank: Super Contributor
timestamp: February 08, 2017, 10:43:57 am
content: Nice work both on pics and fix

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 08, 2017, 11:00:42 am
content: Quote from: TiN on February 08, 2017, 10:43:57 amThanks TiN for your feedback.As i mentioned, i'm lurking to your very nice (KX-) Voltage references to build it by myself. But don't know for now, what i really need. The precision or cheaper one. At times I come back to it

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 11, 2017, 04:31:47 am
content: To complete it,this ominous defective transistor (Q107), be found at many places on my board top marked "132", others have "6G", repairmanual says it's a SNJ132199, under this designation isn't searchable.Anyway, this is a JFET N-CH 30V 0.225W SOT23MMBF4393LT1standard component, available by many distributors.

author: JoeO
author_rank: Frequent Contributor
timestamp: February 11, 2017, 01:08:23 pm
content: Quote from: onesixright on February 07, 2017, 10:12:33 pmDownload the picture.Right click and select properties.Click on the details tab.Scroll down for the properties.

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 11, 2017, 04:22:51 pm
content: Quote from: JoeO on February 11, 2017, 01:08:23 pmYes, the Exif-Data are inside pictures. I left them there.There are several plugins for current browsers, to see them directly.