Modemhead's blog contains a few cases of corroded traces on Fluke meters fixed with 30 awg wire. He doesn't use any insulation on some of the repairs because the wire follows the original pcb layout path exactly where the copper traces are eaten away.
http://mrmodemhead.com/blog/all-posts/
Thanks for that! Yeah, I think I'll get some 30AWG wire-wrap wire for such jobs in future.
(Update: ordered.
)
I had it following the original trace to begin with then realised that was probably pretty stupid given what became of the original trace and bent up upwards, out of the way, instead, lol.
The problem with the original Fluke 80 series is that the user has to remove the case to change the battery and fuses which leads to possible contamination of the pcb board due to dirt, greasy hands, environment, etc. Handling the pcb carelessly and improper taking apart and putting back together could also lead to damage for those traces very close to the edge of the pcb.
Yeah. I don't know if it had happened before arriving at my doorstep, but it is quite possible that I did in taking it apart and cleaning it up (silly me).... but to be fair to me, in that picture, you can see how even the text on edge of the PCB is uncovered and "falling off", so to speak - that's how far out the PCB trace went too it would appear. Fortunately it doesn't look like anything else on the PCB went as far out.
I do think I've become a convert to old 2nd hand stuff versus cheap new stuff now for this kind of equipment.
The time spent reading the schematic, appreciating how it all works, diagnosing the fault, and fixing it was absolutely priceless. I have a terrible problem with lack of self-confidence and always convince myself that I'll just break things or not succeed before I've even started, but actually having a service manual and schematics really made the process much more comfortable to attempt.
Additionally, getting at that trace properly involved taking the internal cover & screen off, which meant an opportunity to clean up the zebra strips, which is something I'd been avoiding doing and turned out to be ridiculously easy to do. The contrast, or rather the viewing angle is still a bit iffy though when viewed from above as opposed to below. Don't know if this is still the zebra strips, or a fault, or just either normal for this device or even just a factor of age on LCDs?
Everything I've been able to test on the meter is now reading spot on.
All in all it's been great buzz of an experience and confidence boost with a nice bounty at the end! Ultimately Dad sent to me one very beat up and thoroughly broken original Fluke 73 and a less mangled Fluke 87; I ended up with what appears to be (touch wood) now a fully working 87 and he now has an equally fully working 73 (one that looked so different, he said he couldn't begin to recognize it when it arrived.) Best of all, I was even able to re-"calibrate" the 73 as it was from an era where doing so involved a single pot and I had a MAX6225 2.5V reference (it was *well* out, which is unsurprising given what it had gone through.)
So he's got a nice, clean, accurate working meter and I've got both a confidence boost and a dream meter that I'd *never* have been able to afford otherwise and all it cost was time, effort and postage.
I'm getting to that point now where I *crave* free broken things, just for the opportunity to try to repair and recover something that would otherwise have ended in a bin somewhere.
Julie
xxx