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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...

Saturday, September 7, 2013

Beomaster 8000 Suddenly Cuts Output Stages Power (Continued)

Again my Beomaster 8000 cut out! I opened it up again, and a quick tracking of the pin 16 voltage revealed that IC4 still did not connect properly to the relay driver. It turned out that the via I thought I had fixed yesterday was still intermittent. The bad contact was on the top side of the via, not at the bottom where I resoldered it. The pic shows the three vias for pins 14-16 from the top after removal of the top part of the shield can.

I resoldered the vias from the top side and now the Beomaster seems to run stable. Note that there is a tendency of the solder to be pulled down below when soldering the via from top on a flat laying board, i.e. the solder bump below gets larger, while from the top it appears that the solder 'vanishes'. This means that the soldering should be relatively quick, just long enough that the bump reflows properly.

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