Beogram 4004 (5526): A New Arrival from New York - First Look

I recently received a Beogram 4004 (Type 5526) from a customer in New York for a full restoration. The unit came safely packaged in a Beolover shipping container (watch the packaging process in the video posted on my 4002/4004 page, it reliably prevents shipping damages). I extracted the unit and put it on the bench:

The hood is quite scratched as if a miniature ice dancer had spun her pirouettes across it..;-):

In absence of new reproduction hoods from the dksoundparts store this hood could be polished back to a decent look, while we wait for them to get their act together (all eyes are on you!...;-). The hood hinges seem in good condition without any discernible cracking. Unfortunately there are a few damages on the inside, which cannot be polished out. But this hood could certainly look more presentable than now after polishing it.

The keypad has the usual use-smudges and also a few scratches:

These smudges come from touching the keys which over time thins and damages the coating. Luckily, we now have a restoration process in place that could make this pad look like new again. Original keypads that still lookg decent can be protected from further decay by installing the Beolover Commander Remote Control for Beogram 4002 and 4004, which allows full control of all functions without needing touching the keys ever again.

The platter is in pretty good condition except one fairly long scratch in the center:

The plinth is also still fairly decent. It only has one small chip on the left corner:

If perfection is desired a beautiful new CNC machined plinth could be installed. They are of much better quality than the original veneer on particle board frames.

The right corner is still pristine:

I removed the aluminum plates and the platters:

The deck looks fairly original under the hood. I found the usual orange fragments from degraded transport lock bushings:

These will be replaced with a Beolover Transport Lock Bushing Set for Beogram 4000, 4002, and 4004.

After this visual inspection I plugged the Beogram in and pressed START. Nothing happened at all. I had a look at the fuses, but both were still o.k.. This suggested an issue with the carriage drive circuit. I manually drove the carriage off the SO ('switch off') switch by turning the carriage pulley a few rotations. After the switch was cleared, the light at the end of the sensor arm came on, indicating that the unit powered up. Pressing the << >> < > buttons yielded no response. Also the platter motor did not rotate. But I was able to raise and lower the arm. So clearly some mayor issues are present in this unit. The platter motor seemed completely seized and I was not able to turn it by hand. A non-standard too-long screw on the motor mounting plate indicated that there some previous interventions already happened:

Overall, I think this unit is a pretty decent candidate for a nice restoration, especially if the cosmetic issues would be alleviated. I am confident that the functional issues can be cured and like-new functionality will be achieved once I am done with my process. Stay tuned!

Beogram 4000: Replacement of a Stuck RPM Relay with a Modern Encapsulated SMD Relay

The Beogram 4000 that I am currently restoring was not able to switch the AC motor to 45 RPM. After replacing the incandescent light bulbs in the control panel it became clear that, while the 45 RPM button would properly illuminate the 45 trimmer pot, the motor would not change its speed. I traced the signal, and it turned out that the relay was broken. The relay simply switches different resistor networks into the feedback of the Wien oscillator thereby changing its resonance frequency.

The issue with replacing vintage relays is that modern units usually are much smaller and also have a more standardized footprint. This vintage relay actually has an unusual pinout in that the two throws are not mirrored across the relay like in modern units, but are different. The translation between modern and vintage relays was made with a breakout board that matches the pinout of the original relay.

I made a short video about this process. It explains the circuit and gives a demo of the new relay click. This is important in my opinion, due to need to get an audible feedback when pressing one of the RPM buttons. All other buttons give a direct mechanical feedback, i.e. this seemed important. Here is the video:

Here are a couple high res shots of the breakout board. Front:

And back:

This design drops directly into the solder points of the original relay.

Beogram 4000: Restoration of a Seized Solenoid to Tonearm Linkage

It turned out that the linkage that connects solenoid mechanism and tonearm was seized in the Beogram 4000 that I obtained from the UK. This meant I had to take the sensor arm assembly out to extract the linkage that I could relubricate it. It turned out that the pin on which it usually rotates had seized in the linkage and that the pin was liberated from its pressfit socket in the sensor arm base. I made a video that explains the issue and shows how to repair it: