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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...

Thursday, January 8, 2015

Beocord 5000 (4715/4716): Recapping the Power Supply, Motor Control, Electronic Switch and Operational Control Boards

And the recap continues! Today I did the remaining electrolytic capacitors of the Beocord 5000 (4715/4716) that sits on my bench right now. Always feels great when all the electrolytics are new! Piece of mind!
The remaining boards were the power supply including reservoir caps and the AC motor cap, motor control, electronic switch and operational control boards:

This is a shot of the Motor Control board that controls the take up motor. Only one Tantalum capacitor to replace:
After replacement:

Here is the Electronic Switch board that manages the keyboard and houses the counter and tape transport monitor. A picture before the recap:

On to the Operational Control PCB. Before:
and after:
Below is a picture of the two recording volume sliders underneath the Operational Control board. I just love this type of B&O 1970s solution. Basically an analog version of digitally simulated sliders on a touch screen...;-). The two red strips are pushed into a white lit compartment underneath the plexiglass cover. This gives the illusion of a linear indicator that gradually changes from white to red as the sliders are pushed to higher volume. The toothed racks drive the potentiometers on the Operational control board that actually take care of the recording volume adjustment:

And finally the pictures of the power supply. Only one electrolytic capacitor directly on the board. Before:
and after:

The power supply has several external reservoir capacitors. This is the 1 uF capacitor on the +12V regulator. Before:
and after:

And the main reservoir capacitors of the power supply together with the AC motor cap. Before:
And after. The two small back-to-back polar 33uF capacitors replace the original bipolar 16uF capacitor on the capstan AC motor:

I guess now it is time to put everything back together for a test! Exciting!

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