What do you guys recommend for cleaning relay contacts? I have Deoxit D5, which leaves a slight residue and CRC QD electronic cleaner (no residue).
Deoxit works very well, the slight residue is intended and helpful. Spray a very small amount
(as little as possible) and exercise the contacts. If there is heavy crud, use a piece of lintless
cloth or Nomex after the small spray to wipe the contacts under pressure (when closed).
Repeat until clean, then a final very small spray.
For industrial environments where some kinds of relay are hard to find or directly there aren't replacement, I use several steps of abrasive papers, starting with a grane, say 240 and finishing with 800. Then, a flow of dry air compressed to clean the dust is about 95% of the cases, sufficient, mainly if not wearing too excessive in the contacts. I used the same technique to renew a 115Hz vibrator from a car radio (Becker Brescia) that stopped to work at all suddenly.
Two relays in a Yamaha R-2000. Both the 'Auto Phono' and speaker relays were intermittent. Dribbled a bit of Deoxit onto the contacts of the 'Auto Phono' relay, then ran a piece of paper saturated with Deoxit between the contacts. Seems to have fixed it, but its always hard to tell when an 'intermittent' is fixed.
When it came to the speaker relay, I had second thoughts as to whether using a cleaner with residue was the best solution. I cleaned that one with the CRC and again, the intermittent seems to have been resolved.
Was really just wondering what others use and if leaving a residue on relay contacts creates any future problems.
When it came to the speaker relay, I had second thoughts as to whether using a cleaner with residue was the best solution. I cleaned that one with the CRC and again, the intermittent seems to have been resolved.
Was really just wondering what others use and if leaving a residue on relay contacts creates any future problems.
Be very wary of using any kind of abrasives (sandpaper, glass fiber brush etc.) unless the contacts already are severely burned to begin with. It will generally mar / destroy the contacts' plating and generally make swapping out the relay entirely only a matter of time. For contacts that are merely tarnished, blotting paper soaked in contact cleaner is plenty abrasive enough.
Exactly! Only very old relays have uncoated contacts that may be sanded but this is very very old practice that worked for power relays in non audio applications. The last 30 years relays have contact material with a coating/metal alloy. Once the pits have been sanded away so is the coating. Useless practice as the problem always returns.
Common design error in japanese gear is the use of relays with gold plated contacts for current switching. Gold is weak and pits easily when currents are switched. Use silver or silver alloy contact relays (preferably with double contacts) for speakers and gold contact relays for voltage/signal switching. I have used Schrack relays with silver or silver alloy ("hard silver") for speaker protection with good results.
Forget about sanding and such practices. Just replace the relays for sealed ones fit for the purpose as described above.
Common design error in japanese gear is the use of relays with gold plated contacts for current switching. Gold is weak and pits easily when currents are switched. Use silver or silver alloy contact relays (preferably with double contacts) for speakers and gold contact relays for voltage/signal switching. I have used Schrack relays with silver or silver alloy ("hard silver") for speaker protection with good results.
Forget about sanding and such practices. Just replace the relays for sealed ones fit for the purpose as described above.
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