Beomaster 2400 Type 2902 - Canada Project Assembly and Last Adjustments for the First Play Event

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. 

Beomaster 2400 Type 2902: Reassembly and new display masks

The Beomaster 2400 has been playing music again in my workshop and I haven't even finished reassembling it.  To complete the reassembly I need new display masks for the tone controls (bass, treble and balance position indication).  Those parts are no longer available from Bang & Olufsen so I have to make replacements. I have done that before on the Beomaster 1900.

Here is the Beomaster 2400 with just the new bass display mask remaining to reinstall. The treble and balance indicator masks are already in place.

Interestingly this Beomaster 2400 serial number uses the same display mask pattern as the Beomaster 1900 units. That is interesting because on later serial number Beomaster 2400 units, but the same type: T2902, the mask pattern changed.

Here is the later mask pattern next to the one this Beomaster came with.

The early mask pattern used a clear square to indicate the current control position with vertical lines displayed on either side. The later pattern blacked out everything except the selected position which now has vertical lines. I guess they had a lot of discussion in the design department over which pattern they liked :-).

It is hard to capture the detail of the display masks but I was able to change the speed and sensitivity on the camera to get this close up of the new masks installed.

With the display indicator masks back in place I could reinstall the back plate and tone control deck.

As with a lot of the Beomaster 1900 and 2400 units this one arrived at the shop with missing and broken feet. Luckily that is another part supplied by Martin Olsen and I installed four new feet on this Beomaster.

The Beomaster is now ready for functional testing. I will start that a little later. For now I will leave the receiver playing an FM station as part of my ongoing burn-in testing.

It looks great and sounds great...and I haven't finished cleaning and polishing the cabinet yet.