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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...

Tuesday, September 9, 2014

Beomaster 8000: Wire Bridges on Microcomputer Board (#9) and Broken Phono Jack

Before I put the Beomaster 8000 back together for a test-drive in the living room together with his play-pals, the Beocord 9000 and the Beogram 8000, I cleaned and de-oxidized all the contacts on the microcomputer board (PCB #9), and had a look at the inner sanctum, the EMI shielded processor cans. Usually one needs to re-solder the few vias that are on this board, since they tend to be poorly soldered...clearly in the 80's the PCB technology was not that advanced, yet. Anyway, what I found in this particular Beomaster was remarkable. Someone already had put in the B&O recommended wire bridges (and then some...), and they were directly soldered to the processor pins. Unbelievable! Here is a pic:

While the soldering appears to have been carried out with some capability, I would never do it this way...the only parts of the Beomaster 8000 that are truly non-replaceable are the microcontrollers that contain proprietary coding, i.e. one would have to extract the code from a working one, if one would want to attempt replacing it with a NOS chip...

Anyway, clearly, this needs to be left as is. I could not risk to expose those rarefied microcontroller pins to another heat-cool cycle. In a way, since the chips survived this assault, this solution is probably the most reliable...several fewer spring based contacts in between the controllers and their slaves...so I decided to just replace the two electrolytic capacitors on this board and move on.

Here is a pic after putting in the caps:

The last thing that needs to get fixed in this Beomaster is a broken phono jack in the 'socket panel' that lost its tabs that prevent it from popping into the panel when trying to plug in the Beogram:

I am working on a creative solution, since not even Dillen of Beoworld.org has this part available.  He said it is rare, since it often breaks...Another day, another 3D print...;-)

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