I want to clean the input devider switches on an old Fluke 8060A DMM because they seem to cause some loose connection.
Would it be OK to sink the whole PCB in IPA (without LCD but including switches and piezo buzzer)?
I can use an ultrasonic bath too.
Should I bring some lubricant (which?) on the contacts after washing and drying them to prevent contact corrosion?
Could the lubricant degrade the high-impedance performance of the switches and environment?
What about the adjustment trimmers on the board?
Hi
It is quite possible that the switch is simply worn out. If so, cleaning isn't going to help.
If it is a dirt issue, you should see some evidence of it visually. In that case, yes, a small brush and something like a Q-Tip with IPA is a good idea. A full soak is normally un-needed and is likely to cause other problems. If you use IPA, get the really good stuff and not something from the local store. Home use IPA often has things like lanolin in it that you do *not* want inside your meter.
If you have a meter that lived a really dirty life and thus must be given a full clean there are better and worse ways to do it. Tear it down as far as you practically can before cleaning. Stuff like plastic panel parts can better be cleaned with soap and water than more exotic stuff. If you soak the pc boards / switches, it's a multi pass process. You do a soak, then a rinse with fresh IPA. You then soak again in yet another fresh batch of IPA and then rinse again in fresh material. Depending on the level of dirt, you may go to further passes or other cleaners. Once the final pass is done, the board should quickly self dry with no signs of residue anywhere. After that, put it in a warm oven with good airflow at a reasonable temperature. The plastic parts on the board will dictate how high a temperature you can run. The lower the temperature, the more hours to bake things out.
Yes, you use a lot of IPA doing this, order up a big bottle of the stuff ....
Bob