Electronics > Metrology

Proper cleaning of contact wipers of precision decade resistor box.


Hi everyone, I scored a 11k to 0.01 ohms decade resistor box for 60 bucks.
Aside from a crooked knob and slightly bent metal it's in really good shape, I already opened it and all the resistors are wire wound.
The problem is that the wipers need cleaning.
I already heard about the wonders of deoxit and I plan to use it, but what should I do with the shmoo which covers the wipers?
Should I clean it first with isopropyl alcohol or I just go ahead and spray the deoxit?
Sorry if this may seem a silly question, but this is the most precision equipment I own and I really don't want to screw up.

Do not cllean the contacts.  They need to be exercised, that's all.  Cleaning will destroy the precision of the values, especially the extreme ranges.  On the high ranges, there will be leakage and on the low ranges there will be contact resistance.

I am assuming this is a 0.1% or better unit.  I have two of them, manufactured probably 60 or more years ago and the contacts have never been cleaned.  They measure spot on with my 6.5 digit Ohmmeter 4-wire.

I will second that, just give the switches a few turns, and they should clean up nicely.
What model decade resistance box, and what are you using to check it?


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