Beomaster 1900 Type 2904: Lighting it up

In the last post of this Beomaster 1900 restoration I was briefly concerned when I powered the Beomaster up and there was no Standby lamp. When I selected one of the sources I could hear the Beomaster power relay engage but most of the lamps were not functioning.

I breathed easier when the power supply tests all checked out and I verified that the lamps all had correct voltages to be illuminated. So it just that the majority of the lamps were shot.

My fix for the lamps is to replace the two volume level indicator lamps, the two FM tuning lamps and the single FM stereo indicator lamp with new incandescent bulbs that I acquired from Martin Olsen of Beoparts. The bass, treble, balance and source selection indicator lamps are all replaced with LED modules that I build (just a 3/4 inch, white, through-hole LED with a 1KΩ series resistor).

I like using LEDs on the bass, treble and balance indicators because the LED lamps run a lot cooler than their incandescent counterparts. That makes it easier on the plastic mask material for those displays. On the source indicators the heat factor is not really an issue but I prefer to use the LED replacements there because they are less delicate and likely to last longer.  All of my LED replacement modules are built to just plug in the board the same as an incandescent bulb with the exception that polarity must be taken into account with the LEDs. Switching back to an incandescent lamp is just a matter of desoldering the LED assembly and soldering an incandescent lamp back in.

Finally there is the Standby lamp which is already a red LED. However the Standby lamp in this Beomaster has failed so it will get a new red LED lamp.

Regarding the five lamps that I am keeping incandescent type bulbs...the reason for that is because those lamps are part of their respective Beomaster circuit function. Changing those to an LED would negatively impact the circuit function.

Here is the indicator board with the most lamps to replace...the FM tuning and source selection indicator board.

Here is the board with new indicator lamps. This picture shows the Beomaster 1900 in Standby mode and the new red indicator LED is working.

I ran through all of the source selection options and all of the new LED indicators work. So do the two new incandescent lamps for the FM tuning.  I didn't check the stereo indicator lamp yet.  I will get to that one when I start bench testing the receiver functions of this Beomaster and an FM antenna is connected.

Here is the bass, treble and balance indicator board as I received it. All three lamps were not working although +15 VDC was measured across them.

Here is the bass, treble and balance indicator board with the LED replacements. I used two LED lamps on each indicator for a better light coverage.

There are two Beomaster 1900 volume level lamps on the volume indicator board. One of the two was burned out.  Here is the board with two new incandescent lamps.

Now the display indicator lamps are all working again. I can move on to adjusting the no-load current setting on the output amplifier stage then see how this receiver sounds playing music.