Electronics > Repair
Fluke 87-I repair
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retiredcaps:

--- Quote from: staze on February 19, 2014, 06:56:52 pm ---could you take a picture of the top and bottom rotary switch in the "off" position?

--- End quote ---
The sun is gone here so I can't use natural light and get a clear focused shot. This is the best I can do with a flash.

The top and bottom pic is shot at angle to get rid of the flash.
retiredcaps:

--- Quote from: staze on February 20, 2014, 12:15:34 am ---Was this with the 87 on or off?

--- End quote ---
All readings I have taken is with the 87 off with no battery installed.  Rotary position is in the off position.
staze:
Perfect! I'll check my switch, and those values when I get home. Maybe also remove those MOVs and check with them out.

Also printed up the schematics today on 11x17 (A3) so I can take notes on values. Will post back later tonight. Thanks!
staze:
Okay, checking Z1:

Z1 to Z2: 9.984M.
Z3 to Z7: 1.1091M
Z4 to Z7: 100.87K
Z5 to Z7: 9.994K
Z6 to Z7: 0.9986K

This is with, as you, an unknown cal 189 with switch off, and no battery. So, Z1 seems to be okay, if a little lower than it should be.

Also with the unit off, and no battery, the two MOVs register as OL both directions (getting somewhere).

E1 also open both ways. R2 still shows as 0.8517M (which seems wrong), and R29 definitely has physical damage... just going to be a bitch to replace with Z1 in the way. C1 checks out (just incase it was shorted). C20, on the other hand, in circuit appears to be bad, and I might spy some cracking around a leg (which may or may not be normal for a ceramic cap of this age). Could you test C20 in circuit and let me know what you get? I get about 0.136nF. I'll lift if I need to, but curious what it shows for you.

At least I'm fairly confident Z1 is okay at this point. =) So, one thing down. Leakage could be coming from one of the clamping transistors (Q1, Q2, Q6)...

Interestingly, it is drawing a very small amount of current when turned off... about 9.80uA. Not sure if that's abnormal or not, but from what I read on Mr Modemhead's site, it should draw nothing when off. So... leakage somewhere?
lowimpedance:

--- Quote from: staze on February 20, 2014, 03:14:20 am ---Interestingly, it is drawing a very small amount of current when turned off... about 9.80uA. Not sure if that's abnormal or not, but from what I read on Mr Modemhead's site, it should draw nothing when off. So... leakage somewhere?

--- End quote ---
Give the PCB another good clean with IPA and check again.
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