Soak a regular piece of paper in Deoxit and run it between the contacts. If that doesn't work, soak some 1000 grit sandpaper in Deoxit and do the same. In reality, it's better to change out relays than to clean them.
For future reference, the continuity function of the multimeter is no good for checking closed contact resistance. Most meters will signal continuity below 100 ohms or so. You need to be able to resolve contact resistance to below 1 ohm (I actually shoot for 50 milliohms). A 50,000 count meter or better is best for this.
Normal print papier (dry) sliding sideways between the contacts works great, i also use this to clean the contacts of Ram sticks, mSata cards, Wlan cards etc.... I have seen a certified HP technician doing this back in 2007, so it's not new under the sun. If the contacts are free accesible like on a Ram stick or so, then a pencil eraser will also work great.
I clean relay contacts all the time but in old pinball machines mainly. For this purpose I almost alwys use Dremel brand wire brushes-brass (softest) part #537-02, carbon steel (med) #443-02 and stainless (hardest) #532-02. A rotary tool with variable speed is a must. For the type of mechanical relays found inside audio equipment, the soft brass will probably be all you need. Wear eye protection if you do this. The dremel brushes hold up well but can still lose a wire now and again. Off brands are essentially projectile weapons.
Agree with Jay. I would add that even softer than the brass wheel is the black nylon(?) brush wheel, which is all that would be needed for this project and no worries of projectiles or even shorts from a metal hair flying into the unit. Also decent for some contact cleaning is vinegar on a Qtip, let sit for a half hour, repeat, wipe off with plain water or alcohol.
Thanks for the video! I have a TFM-6c that needs the same work. Do you have the part number for the thermal pads handy? I looked at the parts stores and there is a huge selection. I wanted to get the correct part the first time.
I use 1000+ grit emery cloth dipped in trichlorotriflouroethane, brake cleaner, or in a pinch, DeOxit. Then I wash the whole assembly down with trich to remove stray fibers, dust etc. I prefer trich to DeOxit so I eliminate DeOxit's lubricant which can trap metal particles that can cause arcing shortening the operable life of the resurfaced contacts. It's a pain to get to a relay's contacts, so doubling the time between resurfacing is a win.
I'm not able to work on such small and intricate parts, so grab a spoonful of salt: an emory board for buffing fingernails would be more gentle, and could be cut to a convenient shape. (Solvents might dissolve the board before dissolving the carbon build-up but you wouldn't know until you tried….)
Well done. I agree, if the relay replacement is available better to replace than to repair. Keep up the good work. Regards from Italy.
Soak a regular piece of paper in Deoxit and run it between the contacts. If that doesn't work, soak some 1000 grit sandpaper in Deoxit and do the same. In reality, it's better to change out relays than to clean them.
For future reference, the continuity function of the multimeter is no good for checking closed contact resistance. Most meters will signal continuity below 100 ohms or so. You need to be able to resolve contact resistance to below 1 ohm (I actually shoot for 50 milliohms). A 50,000 count meter or better is best for this.
Good call on replacing the relay. Ethical!
Just use one of the red and blue erasers. These work perfect just with oxidations and won't damage the contacts ;)
Great work sir, I didn't know relay can be service. I'll put it in use when theres no other option.
Normal print papier (dry) sliding sideways between the contacts works great, i also use this to clean the contacts of Ram sticks, mSata cards, Wlan cards etc....
I have seen a certified HP technician doing this back in 2007, so it's not new under the sun.
If the contacts are free accesible like on a Ram stick or so, then a pencil eraser will also work great.
I clean relay contacts all the time but in old pinball machines mainly. For this purpose I almost alwys use Dremel brand wire brushes-brass (softest) part #537-02, carbon steel (med) #443-02 and stainless (hardest) #532-02. A rotary tool with variable speed is a must. For the type of mechanical relays found inside audio equipment, the soft brass will probably be all you need. Wear eye protection if you do this. The dremel brushes hold up well but can still lose a wire now and again. Off brands are essentially projectile weapons.
Agree with Jay. I would add that even softer than the brass wheel is the black nylon(?) brush wheel, which is all that would be needed for this project and no worries of projectiles or even shorts from a metal hair flying into the unit.
Also decent for some contact cleaning is vinegar on a Qtip, let sit for a half hour, repeat, wipe off with plain water or alcohol.
Thanks for the video! I have a TFM-6c that needs the same work. Do you have the part number for the thermal pads handy? I looked at the parts stores and there is a huge selection. I wanted to get the correct part the first time.
I use 1000+ grit emery cloth dipped in trichlorotriflouroethane, brake cleaner, or in a pinch, DeOxit. Then I wash the whole assembly down with trich to remove stray fibers, dust etc. I prefer trich to DeOxit so I eliminate DeOxit's lubricant which can trap metal particles that can cause arcing shortening the operable life of the resurfaced contacts. It's a pain to get to a relay's contacts, so doubling the time between resurfacing is a win.
I use a glass fibre pencil for oxide removal
I'm not able to work on such small and intricate parts, so grab a spoonful of salt: an emory board for buffing fingernails would be more gentle, and could be cut to a convenient shape. (Solvents might dissolve the board before dissolving the carbon build-up but you wouldn't know until you tried….)
If some contact plating is still left, then tou may use eraser (for pencil writing) and some contact cleaner-deoxit. Sandpaper is too abrasive.
It used to belong to the Fonz...
Cant use anything abrasive on relays, guarantees they will fail again.