This is a follow up to my recent post about the redesigned Beogram Commander remote control board, which now works in both (DC-motor) Beogr...
Sunday, March 24, 2019
Beogram 4004 (5526): Restoration of PCBs and Reservoir Capacitor
After the restoration of the arm lowering mechanism of the Beogram 4004 (5526) that I am restoring right now, it was time to look after the PCBs and the reservoir capacitor. This shows the main PCB in its original condition:
and a detail shot of the 'RPM control' section:
I replaced the electrolytic capacitors, the RPM relay and the RPM trimmers. The original electrolytic capacitors often fail at this point in time, and the relay/trimmers are often oxidized, which can cause platter RPM fluctuations. This shows the rebuilt board
and the RPM section:
I did the same to the output/remote control PCB:
This is a detail shot of the output section:
I replaced the capacitors and the relay, and also added a switch that allows connecting the system and signal grounds together if there is a hum issue (often an issue when using RCA adapters without ground breakout):
The final step of this part of the restoration was to replace the reservoir capacitor. This shows the original unit:
And the modern replacement:
On to the RPM LEDs and the platter motor restoration!