[Ron Ramirez]

Time to replace the output transistors!

[Image: http://www.philcoradio.com/images/phorum/STA225_008.jpg]

New transistors and new mica insulators.

I decided to try applying the heat sink compound to both sides of each insulator with a Q-tip. It resulted in a much neater job:

[Image: http://www.philcoradio.com/images/phorum/STA225_009.jpg]

and now all four transistors are in place:

[Image: http://www.philcoradio.com/images/phorum/STA225_010.jpg]

Notice that there is very little excess heat sink compound, which was my goal.

Notice also that one of the transistors is missing a mounting nut. The receiver was like this when I bought it. Of course the nut is metric...and after spending over an hour looking through a large tin I have filled with various bits of hardware, I discovered that...of course, I don't have one.

I don't want to do a halfway job and solder the pins of this transistor to the PC board until I have a nut and lockwasher in place, and have the transistor secured to the heat sink.

So...unless I can rob one from another receiver I happen to have here, this job will be on hold until next week. I have a currently non-working STA-2000D, and I'm going to open it up and look at it later. I looked inside another Japan-made receiver, a Fisher 202 Futura parts set, but it did not have one.