Products > Test Equipment
Old Fluke Multimeters
wiss:
I accidentally bought a old Keithley 130 a few months back. The display was all pitch black! I scraped of the soft stuff on the back of the glass and then the display got transparent. Now I'l sort of looking for a replacement polarizer/reflector...
Excavatoree:
Just for future reference, I'll ad that the 70 series LCDs have a polarizing film over the glass that often fails. It fails evenly, and the digits fade to brown then light brown. Another forum member (sorry, I forget who) determined that the old polarizing film could be scraped off and new polarizing film could be added. He rotated the polarizer on his, and made a reverse digit meter.
EDIT: Here it is - it was "Sonicj."
https://www.eevblog.com/forum/chat/recovery-of-an-old-fluke-8020a-with-a-bad-lcd/msg32059/#msg32059
ModemHead:
--- Quote from: Excavatoree on June 04, 2015, 02:31:19 pm ---Just for future reference, I'll ad that the 70 series LCDs have a polarizing film over the glass that often fails. It fails evenly, and the digits fade to brown then light brown. Another forum member (sorry, I forget who) determined that the old polarizing film could be scraped off and new polarizing film could be added. He rotated the polarizer on his, and made a reverse digit meter.
--- End quote ---
I've tried that before on a 70-series LCD. I think the post you refer to was what gave me the idea. A razor-blade scraper will get the old polarizer off, and citrus solvent takes care of the adhesive residue. Cut a new piece of polarizer film, (correctly oriented) and the display will be good as new.
P.S. @Deckert, thanks for the plug.
KJDS:
I've just bought a big pile of 8010A. Only tested a few so far and about half are fully working, and despite not having been cal'd in years are within a digit of each other.
drtaylor:
KJDS, If you determine that the main converter IC is to blame for the 8010 units not working, I do have a few 429100 chips for replacement. They've been sitting in antistatic foam for 30 years, so who knows? I'd advise replacing the electrolytics, or at least a careful inspection to look for spew (highly technical term). For top performance a good washing in IPA can fix all kinds of problems. However, try to keep the alcohol out of the ganged switch assembly.
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