Beomaster 1900 Type 2904: New idle current trimmers and output transistor thermal insulators

I started to work on replacing the electrolytic capacitors on the last board, the tone control and FM tuning control board. Unfortunately I ran out of my favorite 2.2uF WIMA capacitors. There is a Mouser distribution center close to me however so the parts will arrive tomorrow.

In the meantime I will go ahead and change out the left and right channel 250Ω trimmer resistors that are used to adjust the output amplifier no-load current. Now is a good time to change them.

Here are pictures of the trimmer replacements.

Along with that change I cleaned off the old, dry thermal insulation paste on the four output transistors that are mounted on heatsinks in the back of the Beomaster. I like replacing that with new Sil-Pad thermal insulators.

Here are the heatsinks reinstalled.