Beogram 4004 (5526): Replacement of Incandescent Bulbs in RPM Trimmer Panel with LEDs

Before the DC motor in a Beogram 4004 (5526) can be restored and tested it is a good idea to rebuild the DC motor control section of the main PCB and replace the incandescent bulbs in the RPM trimmer panel. The RPM stability of the platter drive system depends on all of these components. This shows the RPM trimmer panel as removed from the Beogram:

I removed the covers

and unsoldered the light bulbs:

Then I installed the LED replacement assemblies:

They are drop-in replacements for the light bulbs and include all necessary parts allowing running the LEDs from the 24V supply of the Beogram:

The covers fit like before:

This shows the 33 RPM LED in action:

The LEDs look very similar to an incandescent light bulb. This is the result of using red and green LEDs that are carefully tuned to resemble the emission spectrum of an incandescent light bulb.