BeoGram 400X · Open source part
The original relays in the BeoGram 4000 series wear out with age. I replace them with my own relay PCBs, built around modern Omron relays.
The 33/45 speed change in the BeoGram 4000 series is handled by a relay, 1RL1, driven by 1IC2. Its contacts switch the motor control between the 33 and 45 rpm timing networks, and it is also what changes the speed automatically when the detector finds a 17 cm record. After decades in service the contacts wear and the relay becomes unreliable, and the usual symptom is a deck that won't change to 45 rpm.
I replace the original Siemens relays (8009020) with a relay PCB I designed around the Omron G6K-2F-Y, a well insulated modern signal relay. The PCB fits where the original relay sat, so the main board needs no changes, and it switches more quietly than the original.
Some units, such as the 4004, also have a National relay with a different footprint. I made a replacement for that one too, and it also fits the BeoGram 8000 and various cassette decks.
Both PCBs are my own design, listed under parts, with the design files on GitHub.
BeoGram 400X
A direct drop-in replacement for the original Siemens relays used in BeoGram 4000, 4002, and 4004 models. The relay comes fully assembled with pins and installs using the same process as the original. Soldering required.
BeoGram 400X
A direct drop-in replacement for the original National relays used in BeoGram 4000, 4002, and 4004 models. The relay comes fully assembled with pins and installs using the same process as the original. Soldering required.
BeoGram 8002
A direct drop-in replacement for the original Siemens muting relays used in the BeoGram 8000 series. The relay comes fully assembled with pins and installs using the same process as the original. Soldering required.
More work
LED tracking sensor
The BeoGram 4002 tracks the groove with an optical sensor lit by an incandescent bulb that dims with age. I replace it with a calibrated LED on a small PCB.
LED RPM adjustment lights
The bulbs behind the 33 and 45 rpm scales on the BeoGram 4002 and 4004 panel have usually burnt out after more than 40 years. I replace them with a warm white LED PCB of my own design.
Speed testing with SpinDex
Every BeoGram 400X I restore is speed tested with SpinDex, an open source RPM logger I designed for the BeoGram 4000 series.
RIAA preamp
A new RIAA preamp for the BeoGram 4002, built around the OPA2134 in the same form factor as the original board. The second SMD prototype is built and tested.
Sledge motor
The original sledge motors in the BeoGram 4000 series can get noisy and unstable, and their bearings can't be serviced. I replace them with a modern Portescap motor, with a Maxon motor as the alternative.
Pickup mount
The plastic tab in the BeoGram 4000 pickup mount can break with wear and age. I replace the mount with my own nylon part and flexible PCB.
Restoring the keypad and chassis on a BeoGram 4002
Decades of use wear through the varnish and black paint on the BeoGram 4002 keypad. I strip it, have it professionally painted and refit it to the chassis.
Tell me about your BeoGram 400X and I'll get back to you.