Electronics > Repair

Fluke 85 III

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Gangway:
Have problem with microAmp range selected, display goes into test mode only.
All other ranges operational & cal check on 9100 shows within spec.
Have stripped down main switch wafers & tracks / contacts look ok.
Switch test on all other ranges correct codes.
Cannot find circuit for this rev (101) of main board.
Any ideas?

retiredcaps:

--- Quote from: Gangway on December 03, 2014, 11:01:45 am ---Have stripped down main switch wafers & tracks / contacts look ok.
--- End quote ---
Have you looked on both sides and cleaned out any debris?  See modemhead's 83 III blog entry for ideas

http://mrmodemhead.com/blog/fluke-83-iii-rotary-switch/


--- Quote ---Switch test on all other ranges correct codes.
--- End quote ---
The expected number for the microamp range is 192 for the switch test.  What do you get?


--- Quote ---Cannot find circuit for this rev (101) of main board.

--- End quote ---
You won't find any schematics for the Fluke 80 III or V series.  Only the original series I schematic is available.

ModemHead:
Yes, pay particular attention to the switch on the back side.  Those little fingers between each setting provide a reset while switching functions. Sounds like yours is being held in reset at the uA position.

Gangway:
Thanks for replies, cannot see switch code for uAmp range as it gives two clicks & goes into display test mode ( All LCD figs & symbols). Have removed both wafers and re cleaned metal tracks and wipers.
Continuity checks of switch & reset tracks look ok. Considering mA range works, i must have missed something in the uA range circuit. Will keep at it (when time permits):))

retiredcaps:

--- Quote from: Gangway on December 04, 2014, 05:36:44 am ---Have removed both wafers and re cleaned metal tracks and wipers.

--- End quote ---
Can you post some pictures of the backside and frontside of your meter?  Sometimes, Fluke has several different revisions of the pcb and we might be spot something if you post some clear focused pictures?

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