Products > Test Equipment
Old Fluke Multimeters
idpromnut:
--- Quote from: TerraHertz on March 19, 2015, 02:04:11 am ---Now to PM drtaylor about one of those manuals. Hopefully he's OK.
--- End quote ---
I had PM'd him a while back about getting a manual (I apparently was the first to take him up on his offer) but I never heard back from him after I sent him my address info to get the postage amount. I PM'd him a couple of months after to follow up and still nothing. I am actually kind of worried that something has happened to him, although hopefully nothing serious.
xrunner:
Here's my collection. All in pretty much mint condition. I also have one other 8000A but it's got a problem I have yet to isolate. I think it's the analog IC which I haven't found available yet. :(
kwochele:
Hi Retiredcaps,
Thank you for responding.
1) When the meter first powered on, the DCV was off and I used R5 to set it. However it was not calibrating consistently until I replaced the Measurement Acquisition Chip (MAC) from a donor 8060. After replacing the MAC the meter always settled to the value I set using R5. After replacing the MAC, I cleaned the circuit board including the calibration pots using a can of Radio Shack’s Electronics Cleaner.
2) I heavily sprayed the switches but I did not disassemble them. I found an entry online that mentioned the snap rings could be removed to examine and clean the contacts. I still need to do that.
3) The last digit does fluctuate on the 20V. When I turn on the meter at the 20V selection connected to the D Cell (pretty confident the battery is 1.5620V based on my other meters) the 8060A/AA meter jumps to “-OL” then 1.574 after the display test and then immediately to 1.540, 1.548, 1.553 then it will count approximately 1 count per second 1.554, 1.555., etc until it reaches 1.560. I noticed my second 8060 starts out the same way it just reaches the final value quicker.
4) The input jacks look good and I cleaned them with both WD-40 and then the Electronic cleaner.
Since it does eventually read the correct value after 5 – 10 seconds, could this be normal?
Thanks,
Ken
lowimpedance:
--- Quote from: retiredcaps on March 19, 2015, 02:47:42 am ---
--- Quote from: kwochele on March 18, 2015, 11:35:57 pm ---Any suggestions of what to check are appreciated.
--- End quote ---
Obviously, drtaylor and others are the experts here, but I have some suggestions to at least get the discussion started?
1) When I repaired my 8060A, ACV was way off. It turned out that the capacitor right next to the pot had leaked and while I cleaned up the pcb with IPA and replaced the capacitor, the electrolyte had wicked its way up to the ACV pot. A couple of turns left and right fixed that problem. Maybe give your DCV pots a couple of turns left and right?
2) I don't have a lot of equipment with the push button/switch arrangement, but from what I have read, if they are 20+ years old, they can potentially affect readings and require cleaning.
3) Does the last digit fluctation happen if you use the 20V range? You lose a digit of resolution, but I'm curious if it happens on the 20V range.
4) Have you checked the soldering on the input jacks? Have you tried cleaning them with a q-tip and IPA?
--- End quote ---
Couple more things to check would be that the negative volts rail is stable (U4 and caps) and possibly a dodgy socket for the main 40 pin MAC chip.
Oh also did you have any leaking electrolytics ?.
ModemHead:
--- Quote from: kwochele on March 19, 2015, 10:09:44 pm ---3) The last digit does fluctuate on the 20V. When I turn on the meter at the 20V selection connected to the D Cell (pretty confident the battery is 1.5620V based on my other meters) the 8060A/AA meter jumps to “-OL” then 1.574 after the display test and then immediately to 1.540, 1.548, 1.553 then it will count approximately 1 count per second 1.554, 1.555., etc until it reaches 1.560. I noticed my second 8060 starts out the same way it just reaches the final value quicker.
4) The input jacks look good and I cleaned them with both WD-40 and then the Electronic cleaner.
Since it does eventually read the correct value after 5 – 10 seconds, could this be normal?
--- End quote ---
This has all the hallmarks of a contaminated PCB, assuming you have taken care of any leaking caps and made sure the power supplies are OK. I do not like the sound of WD40 (or Radio Shack electronics cleaner, either) anywhere near the inside of this meter, it is very susceptible to developing leakage currents due to PCB contamination. Dunk the whole thing in 91% or better IPA, scrub what you can get to with a brush, then allow to dry overnight. A fan is a good thing. I'd remove the MAC first, and make sure the socket is clean. Scrub the MAC with IPA too.
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