Featured Post

Beolover SyncDrive: DC Platter Motor Replacement for Beogram 4002 and 4004 (Type 551x and 552x)

Late Beogram 4002 and the 4004 (Types 551x and 552x), which have DC platter motors instead of the earlier synchronous AC motors usually suff...

Saturday, February 18, 2017

Beomaster 8000: Left Channel Output Amplifier Heatsink Components Rework

I started looking at the Beomaster startup circuit relays but the left channel output amplifier assembly was on my mind. I just reworked the right channel output amplifier heatsink components and had found the TR208 transistor loose. Several of the TIP141/146 transistors had mica insulators that weren't in very good shape.

The restoration of the right channel looked pretty good to me so I really wanted to do the left channel even though it appeared to be working fine. This is a restoration project so I pulled the left channel amplifier assembly.

I am glad I did. The left channel TR208 had shifted badly. It was also cracked. The mounting screw that was on TR208 is not the correct one. It is the one that should have been used for the R251 (PTC) mount. The tapered head of the screw looks like it put too much pressure on the TR208 case and cracked it.

Somehow TR208 is still working. I measured it anyway and sure enough, it is still alive. However, I am going to replace it with the TR208 transistor from one of my spare output boards.

I am going to wait until tomorrow to finish the left channel output amplifier rework detour. I need to be well rested before taking on the rework of those TIP 141/146 transistors on the heatsink.

No comments:

Post a Comment

Comments and suggestions are welcome!