Tach Amp

[rg2098]

The cigarette butt trick only works intermittently for me. I took the amp off and scraped the silicone off with the intention of re-doing some of the solder joints. Anyone have an idea of how to get the silicone off around the traces without scraping them off? I got the big chunks off with a small knife but now I need to do the detailed work. I tryed a soldering iron with the hope it would melt off under the extreme heat but no luck. It's some pretty tough stuff.

[dieseldiehard]

I was able to get most of the potting compound off with an exacto knife on one tach module.
You are right, it is very sticky stuff. I scraped one almost clean and I never found a bad solder joint. I believe there may be some other failure mechanism in these stupid modules. Whatever it is, it's is very commonplace. The cigarette (or other wad of something) in the cap is temporary in some of the modules, but then they start failing again - Darned VDO tach thingies!

[83sdturbonut]

Originally Posted by rg2098

The cigarette butt trick only works intermittently for me. I took the amp off and scraped the silicone off with the intention of re-doing some of the solder joints. Anyone have an idea of how to get the silicone off around the traces without scraping them off? I got the big chunks off with a small knife but now I need to do the detailed work. I tryed a soldering iron with the hope it would melt off under the extreme heat but no luck. It's some pretty tough stuff.

I use small screwdriver and needle on joints,it take time. Idid two amps it workd okey for me after soldering each joints.Good luck. Ivan.

[admanles]

I used a bamboo skewers with the sharp points rounded off a bit. Worked pretty well at getting the sticky stuff off and not scratching the circuit... however, I did not find any broken or cold solder joints, thought it might be the pins being loose... but within a couple of weeks, it was back to working whenever it felt like it.

Les

[dieseldiehard]

I think the pins losing contact may be involved in many instances when these things stop working. I tried some Cramolin contact cleaner/lube on one but that didn't fix it.
Still a mystery.