Beocord VX 5000

27th August 2008

This machine gave the correct random light show in the display followed by going into standby mode when the mains power was connected, indicating that the power-on reset circuit was working correctly. However, every attempt to turn the machine on after that resulted in an automatic shutdown a few seconds later. Disconnecting the collector of the fan motor reset transistor QR1654 proved that the fan motor circuit was where the fault lay. The fan impeller was free to turn but the over-current trip was being operated as the voltage at pin 6 of IC1653 was 2.8V instead of the more usual 1.2V. R1655 (47R) was checked and found to be the correct value so attention was instead turned to the UNREG 16V line which was rather high at over 21V. The machine had been imported from Germany and was fitted with a 220V mains transformer, fitting a 240V replacement restored normal functioning. [Beocord VX 5000]