Electrical gurus, Duane?

[driggs]

Anyone ever used this "silver conductive grease"? Doing a cleanup on my instrument pod, and trying to overcome some corrosion issues on the indicator bulb circuit board tabs (where the black plastic bulb holder sockets plug in). I cleaned up all of the visible corrosion, but am still having trouble getting a 'perfect' connection when the socket is plugged in.

This stuff is not to be confused with "dielectric grease" which insulates and protects connections....this stuff is supposed to actually be conductive. So if I coat the tabs on the socket and on the circuit board, I should be able to get a nice solid electrical connection.

just wondering if it works as well as I hope it will....if I stick my ohmmeter into a dollop of this stuff, will I get zero resistance? Advice?

Duane, have you used this stuff in your travels? Click the image to see the whole thing.

[Ken in Oklahoma]

I have no experience with conductive silver grease, but if an electrical connection is alrady compromised with oxidation, corrosion, or even crud, I strongly doubt that conductive silver grease is going to fix the problem.

And if a connection is already clean, is conductive silver grease needed? After all one of the things the dielectric grease does is to forestall corrosion.

But then I hve no experience with conductive silver grease.



Ken

[ME 109]

These connections can be a pita even with clean, non-corroded copper tabs.
Carefully bend the copper tabs further out to assist in making contact.
I think sometimes there are alignment issues with the copper tab and the steel tab of the bulb socket.
From memory, the contact point between copper tab and bulb tab is close to where the copper tab folds over. What I'm saying is that just by bending the copper tab out at the bottom doesn't ensure contact with the bulb tab.
A little piece of foil slipped in with the bulb holder can assist.

I wouldn't use conductive grease as it is treating the symptom and not the cause, and could create other problems.

[Ken in Oklahoma]

I had problems with the lamps in my '76 R75/6 that drove me crazy for way to long. I did the usual thing of brightening up contacts and such, but the problems kept on recurring. Finally I determined that I did have a connection problem, but one that hadn't crossed my mind. The problem was that the connection between the pin(s) (that plug into the big square connector) developed a bad connection between the pin's base and the flexible circuit board.

The fix I cam up was to peel off a bit of the flexible cover over the copper etch. Then I ended up repairing the connection "fix" by wrapping a single turn of thin copper wire around the base of the pin and soldering the connection. Then the free end of the copper wire was laid onto the bare copper etch and I soldered it there. I may have "repaired" the etch coat with clear finger nail polish or clear varnish, but that bit of memory seems to have come up missing.

While you're into your cluster you might take a hard look at the pin to etch connection and wiggle the pin if you can.

Ken

[driggs]

I think sometimes there are alignment issues with the copper tab and the steel tab of the bulb socket.
From memory, the contact point between copper tab and bulb tab is close to where the copper tab folds over.
I wouldn't use conductive grease as it is treating the symptom and not the cause, and could create other problems.

I think you've hit the nail on the head here...I used a 12 volt battery to test the connections as I plugged in the bulb sockets, and as you describe, the bulb will light just fine when the contacts on the bulb socket touch the lower part of the copper tab. But when the socket is pushed 'home' against the circuit board, those contacts on the bulb socket come into contact with the part of the copper tab where it folds over the edge of the plastic base. As soon as the bulb holder 'clicks' into place, the bulb would lose good contact with the copper and flicker, or go out altogether. So I thought that the conductive grease might be an option to get the lower part of the copper tab to do some of the work in making the connection instead of relying on the bent part of the tab.

Maybe shimming the copper tab out with alum foil will force the bulb socket to make a better connection.

[driggs]

The problem was that the connection between the pin(s) (that plug into the big square connector) developed a bad connection between the pin's base and the flexible circuit board.

While you're into your cluster you might take a hard look at the pin to etch connection and wiggle the pin if you can.

Ken

Good advice. That's why I used a battery to light the bulbs while inserting them/wiggling them around. I was able to determine that the pins are good, the problem lies with the bulb socket/copper tab connection. Thanks for the help.