IMPORTANT: if you do this, make sure you have the pinout for your display handy an the 8010A service manual and you read it end to end. This entire job is painful and frustrating. If you can, find a donor meter for a display and save yourself a few hours.Got a Fluke 8012A for just over a tenner on ebay with a knackered display. This has low ohms so is handy for tracing out shorts and measuring shunts etc. I have an 8010A already.
Cleaned all the crud off it and it looks reasonable apart from the display:
Thought it was a mains only model but cracked it open and found battery box in it. This was removed as were the batteries. In these, there is an LM317 configured as a current source to charge the NiCd cells that were originally present. I converted this into constant voltage by cutting the regulator adj line, jumping the current setting resistor and using a 240R/330R voltage divider centered on the ADJ pin to out/ground. This gives constant voltage mode of around 3V. This is just above the 2.8V of a fully charged set of NiCd cells.
At this point I noticed it was a bit slow to start up. After looking closely at the electrolytic capacitors, a couple had leaked electrolyte. All the capacitors were replaced instantly as a precaution.
Body count:
Working nicely after that.
On to the display. A standard 3.5 digit LCD module fits nicely in these. I used a Display Elektronik DE113-RS-20/12.2 from bitsbox.co.uk (merely £4)
To replace the display requires some patience. The front panel of the meter was removed and the old display was removed with the zebra strip. As you can see the new display looks nothing like the old one so it's Kynar time:
The display assembly needs modifying to fit the new LCD. Remove the two supporting strips from the rear of it and round off the inside edges.
Before:
After:
Then fold the LCD pins back on themselves like this:
Then test fit it into the display assembly:
After that, the hard bit. Apply Kapton to the back of the LCD to protect it from solder blims and write the pin numbers on the kapton. Refer to the LCD datasheet for the module that you picked and solder an 8 inch (yes that long - I did mine slightly too short) piece of Kynar to each in use pin. Heatshrink the pins. Don't try and do it without heatshrinking - it's a world of pain you don't want to get into. Feed each half of the LCD's kynar wires thorough the display assembly's two holes on the rear.
IMPORTANT: after each wire you solder on, write the pin number of the wire on the kynar so you know where it goes later! How do you do this? Binary encoded as dots and dashes where dot = 1 and dash = 0. -.--. on the end of the wire means wire 22. Saves a lot of bleeping out and bleeping language later.
NOTE: there is a wiring error here. Check your instructions not my picture. pin 3 is missing and backplane pin 40 was disconnected eventuallyNow kapton over the edge of the display connector on the board.
Next TRIPLE CHECK that you got all the wires out that you need and that you labelled them all. I didn't and had to throw an hour away rebuilding it.
Put the display module back into the meter and put the front panel back on and route the wires around the edges of the display module:
Then wonder what unholy hell you've left yourself to deal with. I've started wiring here.
Wire everything according to the pin numbers correlated with the Fluke instructions. If you made the kynar too short (I did) it may not reach to some pins so you'll have to extend it. Then tie down the resulting Cthulhu with a couple of cable ties.
If you screwed up it will then look like this and you will have to go and bleep it out with a meter.
After 40 minutes of debugging, it works:
At this point treat yourself to a nice drink and promise yourself you're never going to do this again. Until the next time (this is the third one of these I've done).