My question about these old DMM is how long will they keep on working accurately and be useful. I mean they are all more than 20 years old, so will they not need recapping if they use any capacitors in the circuit inside these DMM?
Or are they OK in this respect, and will last much longer without having to get serviced?
I can speak from my experience. I believe that my experience is typical based on what other people have written.
1) There are electrolytic capacitors in these meters. And yes the electrolytic capacitors can leak after about 20 years, depending on how the meter was stored.
2) The good news is that most of the time, replacing the capacitors and very careful cleaning of the board. I scrub the board with a small brush and 99% Isopropyl alcohol (IPA).
3) There are also issues with LCD displays. The display can be fuzzy or have bleeding.
4) The other issue is that the zebra strips in the LCD connections may have to be cleaned with IPA and re-assembled.
5) The other issue that I have seen is a shorted zener diode which is parallel with the DC jack / battery. The Zener is to protect from reverse polarity and over-voltage.
So if you are buying one, check for a nice clear LCD display. Check the battery compartment for corrosion.
Remember the HRC fuses are expensive around $10.00.
When they are restored, these meter are remarkably accurate.
[ I had one very tricky repair. At some point in its life it had been overloaded causing failure of the MOVs on the input. This contaminated the board with carbon. You tell this if you set the meter to read the highest ohms range and it doesn't read OL. I had almost given up. Then I cleaned the board in a ultrasonic cleaner for 1 hour at 50C. Then 1 more hour with clean water. I tried the board. This fixed the problem. ]
The performance of the meters did not happen by accident. Fluke engineers, including Dave Taylor the designer of the 8060A, put a tremendous amount of effort into choosing the best components for the application. The protection circuits in these meters is also very good.
I have about 6 8060A, including one of the Blue IBM units. I also have an 8024B.
You should have at least 1.
Jay_Diddy_B