Hi all
I’ve not posted here before though thought I’d try here for some advice about fixing my Fluke 189 meter. I’ve read as many threads here and elsewhere as I can find on the thing but haven’t sorted the problem sadly. I’ve had it since new and it’s been a great tool, recently it started giving leads errors (common I know) and the 10A current range was not working, power on went intermittent too. I sorted the power with new battery connector hardware. I got brief function after that with the meter all working so I think most of the board will be good. I also had noticed during the battery clip repair that one of the 10A fuse clips was loose, thought that was the rest of the problem. I see it’s normally both glued down and soldered at the two small tabs. Didn’t seem to solder well at the tabs despite cleanup, so I cleaned up and tinned the whole pad below it , plus the back of the clip and attached it well with solder as pictured. I’ve put up pics of the whole board as well as that repair in case it helps. All seemed good, I’ve got continuity from clip to other components on the board - the black ?? component below it. Repair doesn’t seem to have damaged anything.
I reassembled and frustratingly still get a leads error. The meter boots up fine with no leads attached when on a current range so I guess it *thinks* it’s got current test leads connected even when it has none at all. My intuition says the problem has nothing to do with the original loose fuse clip and repair.
I’ve cleaned the input sockets they look fine. Good continuity to the PCB. I see there are split connectors in them which are used on the current inputs only to detect banana plug connection. Electrical rather than the IR detection seen on more modern models. One half of the banana input goes to two separate brown 1 Meg resistors, one for mA and one for A. Resistors seem good. Those resistors connect to what I guess is the base of an SOT transistor , shown on the near edge of the board in the middle in pic 4, one transistor for each input, continuity good. From there I have no clue how the input detection is working. PNP or NPN transistors? Any chance a transistor has failed?
I wish I had a schematic for this board but none seem to be out there.
Overall the board looks clean with no obviously damaged components or joints.
Any help with info that might help repairing this appreciated, it’s a great meter and I think it should be repairable! I’m not seeing any professional services fixing older Flukes here in the UK though again if I can’t fix it I’d try that route if it were available.
Steve