The motor amplifier output at 45 RPM speed selection will also go over 6 VRMS without distortion. It's frequency is a little higher than the service manual as well though. The manual asks for 57.3 Hz and I am measuring 57.96 Hz.

The next step is to start buttoning down the Beogram so I can do the rest of the adjustments and get it to the point I can really evaluate the performance of the new cartridge mount from Beolover. I am hoping to reach that step sometime this weekend.

I believe I have the platter motor amplifier adjusted to a good starting point now. First I set the control panel speed trimmers to the center position of the trim pots.

Then I adjusted the main board speed trimmers 1VR1 (33 RPM) & 1VR2 (45 RPM) so the motor output (with the appropriate speed selected) frequencies were as close to 42.3 Hz (33 RPM) and 57.3 Hz (45 RPM) as I could get them. Once that was done I readjusted the motor amplifier output signal so it was between 6 VRMS and 6.5 VRMS for both speeds.

The output looks pretty good as measured on my oscilloscope. I will have to recheck the speeds when I get the platter and belt on.

Here is the 45 RPM speed output

Thanks John upping my learning vurve

Hi John,

Awesome thread!! I scanned the 24V bulb circuit diagram and posted it on my blog:

http://beolover.blogspot.com/2016/01/beogram-4000-alternate-circuit-diagram-2.html

Rudy

That's a nice quality scan, thanks!

I found this picture of the BG4000 control panel 3IL3 & 3IL4 from my first Beogram 4000 unit. It has a slightly different board than my current one but it also has the two lamps in series so they are 12 V lamps. This second BG4000 turntable has the board that can be wired for either the 12 V or 24 V lamps which is what was confusing. But that is the goal of this 400x thread...to collect and show as much information on these great turntables as possible.

Tonight I installed the replacement tracking sensor lamp source I got from Beolover. It is an LED replacement with a built in trimmer resistor for fine tuning the sensitivity of the tracking sensor. I like this integrated replacement as the original trimmer was added on later and hangs off the tonearm transport assembly. This replacement looks cleaner. It is also a drop in replacement so the original can be restored if I want to later.