Beogram 400X Relay Replacements

After I changed all the capacitors on the mainboard of the Beogram 4002 (5521) I am restoring right now, the 45 RPM circuit stopped working while listening to a record with The Boss. I sought help in the schematics and decided to replace the two main relays (part 8009020) as suggested by Rudy from Beolover.

I couldn't find any drop-in replacements with the same specifications and dimensions and because of the customs when importing from US (Beolover) to Denmark I decided to make my own version of Rudy's relay replacement part.

I decided to use almost the same relay as Rudy (I'm using the highly insulated Omron G6K-2F-Y) and with a little help from the schematics and a calliper, I managed to create my own PCB schematics using Fritzing.

After receiving the PCBs and relays from China I soldered everything (first time working with SMD) and tested it in the Beogram 4002. It was working as expected and even quieter than the old Siemens relay.

I quickly found out that it was super difficult to solder all the small header pins vertically and parallel to each other so there was only one thing to do! I 3D printed a small base with room for the pins and a PCB which I glued to the top of the base. The soldering base makes it super easy and fast to solder these replacements. I just add the pins and fit another PCB on top of them and solder. Voilá!

I wasn't completely satisfied with the clicking sound coming from the relays when lowering the tonearm or switching between 33/45 RPM so I decided to create a 3D hood with sound dampening material inside.

The sound dampening hood was made in Tinkercad with almost the same dimensions as the old Siemens relay so it's easy to replace. I printed it in PLA as usual with a width of 0.2mm and a temperature of 204 °C.

After playing around with various sound dampening materials I decided to use Melamine Foam which dampened the sound the most. I added a drop of glue to the inner top of the hood and added the foam.

With a small indentation in the hood, the PCB could easily be slipped into place. It was locked in place with a drop of glue and soldered back on the BG4002 for further testing.

It works perfectly and it's almost silent. You'll have to struggle to hear it. I'm quite sure that B&O would use a silent relay if it existed back in the 70'ies so this is as good as it gets!

Update, 02-01-2020:
I got some feedback on the sound dampening hood for my Siemens replacement relay for the Beogram 4000 series. For some customers, the relay hood was a little too big because of the surrounding components, so I created a smaller version of the hood. It is 2mm smaller on each axis and uses less PLA so it should fit easily now :) Furthermore, the corners are rounded so it looks and feels better.

Update, 11-02-2021:
While restoring a 4004 I needed a replacement for the National relay as well. The footprint was a little different but it was still fairly easy to design it. This time in black PCB. Looks good! It also fits the Beogram 8000 and various cassette decks.