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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...

Sunday, February 26, 2017

Beomaster 8000: Second Burn-in Test Results

I ran this second burn-in test for eight hours playing music with the Beomaster volume level at 4.0. After the eight hours I put it into standby mode for three hours then started playing music again. This time everything went smoothly and the amplifier sections are working great.

So far no hiccups on the power relays or anything else. I checked the temperatures of the heatsink mounted transistors (IC201 - IC206) and the two BF857 transistors on the output amplifier board (TR207 and TR211).

The heatsink mounted components measured around 20°C when no music was playing and about 27°C when playing music. The TR207 and TR211 transistors measured around 40°C at idle and around 50°C when playing music.

That should conclude the work on the power supply, output amplifier boards and preamplifier board work. Currently the Beomaster is operating with substitute Filter & Tone Control and FM tuner boards. Those were components that were next in line for restoration so now I have the repair task to add to that. While I work on the remaining boards to restore I can continue running the Beomaster so it gets more burn in time. It is also nice to listen to while I work on the FM boards and the Filter & Tone Control board.

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