• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

SA-8100 Output transistor insulators

K

kpmadden

Member
I'm in the final stages of restoring my SA-8100 amp, having replaced the caps, transistors, and a few fried resistors. It is obvious that something really bad happened to the power amp board, so I'm replacing the output transistors as well, assuming they suffered stress along the way. When removing the original TO-3 devices, I discovered that the original heat sink insulators seem to be glued on. I'm really hesitant to go at them with a hard tool. Is there are solvent to dissolve the adhesive, so I can attach new mica insulators and thermal grease? Thanks, Keith
 
Register to hide this ad
I do not know how I removed it but I guess I tried petrol / alcohol / acetone first and then 100% sure I used the scraper.
At mine, I had to mechanically rework it anyway, since they managed to produce a "hill" in the heatsink, around one of the holes.
The "hill" is on the left hole of the mounting location in the middle...
pioneer-sa8100-heatsink1.jpg
 
Yeah that glue is a real pain, since you want a smooth flat surface for new insulators. I think a sil pad maybe a bit more forgiving flexible than mica if the surface is uneven.
 
I did finally manage to get the glue and the old mica cleaned off. I used a mixture of 90% isopropanol and naphtha. I then gently scrubbed the area with a little brass brush that was in my de-soldering kit.Like Mr.gslikker, I found that the heat sink was not as flat as I'd like, but mine was not so far off that I wanted to mill it down. Thanks for your help!
 
You must log in or register to reply here.
Back
Top Bottom