The no-load (idle current) adjustments and the power supply adjustments were made earlier. The lamps were replaced and I performed a little test measuring the source switching volume mute circuit. Now it is time to finish up a couple of adjustments for the FM tuner, partially reassemble the Beomaster 2400 and see how it sounds.
The service manual has a couple of easy FM tuner adjustments that can be made.
One is for the FM tuning voltage on the FM tuner potentiometers.
FM1 preset is turned to the dial stop for 88MHz and a test point (4TP1) is measured across resistor 4R1. The voltage should be set to 4.7 volts using trimmer 4R2.
The same measurement point is used again to measure FM5's potentiometer set to 88MHz. On this adjustment, trimmer 4R8 is adjusted to get 4.8 volts (across 4R1).
Another quick FM tuner adjustment is for the tuning indicator lamps. Test point 2TP3 is shorted to ground and the Beomaster 2400 is turned on by selecting an FM source. Trimmer 2R31 is adjusted so the brightness level of the two tuning indicator lamps are equal brightness.
Finally it is time to hear what this Beomaster sounds like after all of the restoration work.
I connected up an iPod Nano to the Beomaster 2400 Tape source input, my FM antenna to the PAL FM plug and the Speaker 1 outputs to the Beovox S-55's that I keep next to the test workbench.
Standby lamp on...
Tape source on
FM1 on
The Beomaster 2400 sounds good. The control sliders for Bass, Treble and Balance all work nice and cleanly. A nice milestone in a project to hear music coming from the restored components.
I will do more reassembly of the Beomaster 2400 cabinet and continue testing. I will test out the remote control functionality next. That includes testing out a nice Beogram 4004 as the Phono source. In case you didn't know, the Beogram 4004 can be remotely controlled from a Beomaster 2400.
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