[William Dudley] picked up a Fluke 8840A bench multimeter at an auction, but was unfortunate to locate out that it was reading through resistances inaccurately. It was also lacking the optional board to permit AC measurements. Desiring to use the if not lovely meter, he set about restoring and upgrading the gadget.
Luckily, the 8840A was from a time when Fluke used to overtly publish schematics in its manuals. So, merged with taking a search at some shots on-line, it was simple for [William] to recreate the initial AC “Option 09” board to empower the wanted performance. As is normally the way, his endeavours did not get the job done very first time, but just after some bodge wires had been put in, all was very well. [William] reports the measurements are “reasonable, it’s possible even sufficient” with no calibration undertaken.
Fixing the resistance issue was simple. It turned out to be corrosion on the selector switches, disclosed when high-resistance measurements had been exact, but lower-resistance measurements weren’t. A little bit of flick-flacker with some get hold of cleaner sprayed into the switches bought items operating once again nicely.
It is nice to see old components restored to complete functionality, specially when it’s as attractive and properly-created as an outdated Fluke meter. Bringing back again previous equipment from the dead? You know we wanna hear about it!