My examination of the Beocord power system continued with the regulator and power supply boards.
The regulator board houses the +5 VDC and ±15 VDC regulators, all situated on the large rear heatsink. I always inspect the heatsink compound and mica insulators for dryness, and thankfully, this Beocord appears to be in good condition.
I’ve encountered instances where these components showed deterioration, but not in this case.
With the regulator board cleared, I shifted focus to the power supply board’s voltages. After confirming the ±15 VDC, I discovered an issue: the 6.5 VDC line connecting the power supply board to the microcomputer/display board was absent. This point, from D15 cathode to ground, should register around +6.2 VDC when the Beocord is powered on (not in standby). Instead, I only got a 15mVDC reading.
After confirming the regulator and power supply boards were not the source of the problem, I determined the issue originated at the destination. To investigate further, I removed the front glass and control panel. The schematic indicated that the 6.2 V line from the power supply connected to capacitor C56 on the microcomputer/display board. Given its nature as an electrolytic capacitor, it was a prime suspect, and upon removal and testing, it proved to be faulty.
Finding a faulty electrolytic capacitor was positive news, as they are a common point of failure in vintage audio equipment and frequently replaced during restorations. However, these capacitors in Beocord systems are known for their longevity and aren’t always replaced. This discovery confirmed that a recap was necessary for this particular unit. Replacing C56 with a new Nichicon 105°C capacitor brought the Beocord back to life.
Play, Fast Forward, and Reverse functions are now operating smoothly, marking a significant step in the restoration process.
The display, however, is missing segments and should read 06:25. This is another expected issue, and I plan to address it by replacing all of the original display LEDs with new SMD (surface mount) LEDs. I will also use LED replacements for other Beocord light bulbs, similar to previous restorations documented on the Beolover Blog.
Currently, I haven’t been able to evaluate the Beocord’s audio output or recording capabilities. My next step is to connect the Beocord to an amplifier and measurement equipment to assess its “before” performance prior to proceeding with the capacitor replacements.