Fluke 8020A Repair HELP MULTIMETER DOES NOT WORK ANY RANGE

[elnegociadorweb]

Hi i have a problem with my dad's fluke 8020A. The screen is fine, it turns on and moves the points on the screen (.  .  .)

Please help:
-MULTIMETER DOES NOT WORK ANY RANGE
- the on-screen indicator of the battery low is always active (BT)
--capacitors ok
-pcb clean
-Battery New

[retiredcaps]

Fluke 8020A manual at

https://archive.org/details/FLUKE_8020B_Instruction/page/n75/mode/2up

BT indicator - see page  4-11.

As no readings, check R2 fusible resistor.  It should be 1k ohm.

[elnegociadorweb]

Hi, thanks, the multimeter is the 8020A. Will the 8020b manual serve me?

[retiredcaps]

A manual here.

https://www.manualslib.com/manual/564456/Fluke-8020a.html

[coromonadalix]

I was thinking it may be based on an icl7106 dmm chip,  but Fluke had different  ic instead ??  But it was supposed be an 7106 predecessor ??

Some story : or copy cat  loll
https://hackaday.com/2017/01/31/get-to-know-3%C2%BD-digit-adcs-with-the-icl71xx/
https://www.eevblog.com/forum/testgear/history-of-the-fluke-8020-series/

I recall they where still Intersil branded ??


Some display revival and notes

https://www.sbprojects.net/repair/fluke8020a/index.php

[coromonadalix]

And this section:

To make it functionally different, Intersil masked off the switch that allowed the 429100 to auto-range between 200mV and 2V ranges (which was a Fluke patent). This made the 7106 unsuitable as a direct, drop in replacement for the 429100.  But Fluke found out that the silicon inside the 7106 still sported a Fluke logo, and a lawsuit ensued. This was settled out of court, since Fluke could not afford to lose Intersil’s fab facilities. But the 7106 was now available to all for use and would end up inside a large number of products built in those days. You can read [drtaylor] who worked at Fluke during the time reminisce about this over at the EEVblog forum


And this sale if you need a new dmm chip
https://www.ebay.com/p/1845868863

[elnegociadorweb]

Hi.
upgrade:
r1: ok
r2: ok
the fluke 8020a will not turn on from the battery eliminator connector!
I suspect the lm358n
  What voltages should the 429100 chip have?