old scope & contact cleaner

[Walter Harley]

How safe is aerosol contact cleaner (e.g., Caig Labs D-5) for the switches
on old test gear? Specifically I'm worried about whether if that stuff
soaks into a circuit board or the wafer of a rotary switch, will it change
the electrical properties?

And, same question re control cleaner/lube for the pots. If some of it gets
sprayed around and lands other than where I meant it to, will it cause
problems?

Thanks!

 

[Joerg]

Hello Walter,

How safe is aerosol contact cleaner (e.g., Caig Labs D-5) for the switches
on old test gear? Specifically I'm worried about whether if that stuff
soaks into a circuit board or the wafer of a rotary switch, will it change
the electrical properties?

I don't know that one. Most of my sprays are from "Kontaktchemie" in
Germany. There they have contact cleaners that cleans aggressively but
can be too aggressive at times. They also have sprays that are less
aggressive and that's the ones I use for electronics. Usually these are
(were?) marketed for "tuner repair". But it's been a long time, I use
this stuff sparingly, also for environmental reasons.

And, same question re control cleaner/lube for the pots. If some of it gets
sprayed around and lands other than where I meant it to, will it cause
problems?

Pot cleaning with sprays? To be honest I have never seen a long term
success there. Sure, the pot won't crackle at the end of the day. But a
few weeks later it's usually the same old problem again.

Regards, Joerg

http://www.analogconsultants.com

 

[tekamn]

Hello Joerg,

yes, "Kontakt 60" from the manufacturer you mentioned is well known to
interact with older PCB material. The contents of the spray get soaked,
and lower the reistance of the pcb. And this contamination is permanent
if you spray too much.

this makes "funny" results on e.g .older boards or rotary switches:
Once the board is soaked, it can catch fire when voltage is applied.
Older roratary switches with pcb base get completely damaged..

So extreme care should be taken just to apply the stuff on the metal
contacts only.

"tuner 600" is more mildly, I would recommend this to for maintenance
for older T&M gear.-- but that's just my 2cts. ;-)

For pot cleaning this recipe helped my a lot of times: Drill a very
small hole into the pot housing (1 mm drill/ 0.05 inch drill). Apply
one drop of "Kontakt60" via a syringe into the hole (To get the stuff
from the spray can: spray small quantitiy into a small glass, and fill
up into the syringe). Now turn the pot a dzen times left/right.
Re-apply a second drop and repeat. Usually, pots I treated this way did
perfect service for 2-4 years -- so I guess this is well worth the
efforts.


hth,
Andreas

 

[Joerg]

Hello Andreas,

"tuner 600" is more mildly, I would recommend this to for maintenance
for older T&M gear.-- but that's just my 2cts. ;-)

That's the one I use.

Regards, Joerg

http://www.analogconsultants.com