Based on the review of the Siemens VDO RD3 01 service manual, we recommend:
Without the manual, it is a brick. With the manual, you can resurrect a classic head unit for under $10 in parts (capacitors, grommets, thermal paste). siemens vdo rd3 01 service manual full
Per page 23 of the manual:
: Uses a VDO-proprietary laser pickup assembly. Common service issues involve the loading rollers or the laser lens alignment. Connectivity ISO Blocks Based on the review of the Siemens VDO