I recently finished up the restoration of a Beogram 4002 (5523). My customer decided to add both the Beolover 4002 Commander MkII remote control receiver (it works together with a matched Apple remote) and the internal RIAA pre-amplifier. I developed these two upgrades a while ago. More information about their performance and installation is given on the 4002 Commander page on the blog and in this post about the development of the RIAA amp. Both boards are available to other enthusiasts. Just send an email or use the contact form on the right.
This shows the two boards together:
The board at the bottom of the picture is the Commander MkII remote receiver board. The MkII version comes with a repeat function, which uses the CD4 indicator on the keypad cluster as indictor. It is a plug-and-play installation. The board installs into the keyboard header on the main PCB and is bolted into place using one of the screws that holds the PCB down.
The RIAA amplifier is soldered directly into the output relay solder points. This shows the output board as I rebuilt it with a new relay and grounding switch:
For the installation of the RIAA amp I needed to remove the relay and the switch again to make space for the board and the connectors. This shows the output PCB prepared for the installation together with the RIAA board upside down:
The red 3D printed component serves as spacer to elevate the board above the black in- and output board headers. This shows the board after installation:
The original headers are still accessible, i.e. the Beogram can easily be configured in its original way by plugging the cables into the original headers instead of the white amplifier connectors.
This shows both installed in the Beogram:
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