Beocenter 2200

20th May 2016

The fault with this set was that FM radio reception was marred by heavy pops, crackles and clicks and was in mono only, AM reception and all other functions being normal. The voltage at 2TP7 (pin 6 of the FM IF amplifier and detector IC 2IC2, LA1235) was low at 0.6V instead of the correct 6.1V, although the voltage at pin 3 of the stereo decoder IC 2IC3 (LA3390) was correct at 4.5V. Disconnecting pin 6 of 2IC2 saw the voltage at the pin of the chip return to normal so leakage in 2C65 and 2C68 was suspected, however the actual cause of the trouble was the trap coil 2L12. The set will function with this coil removed if the input and output connections are shorted together, however in this case a replacement from a scrap set was fitted. This restored correct functioning to the radio section. [Beocenter 2200, Beocenter 2100, Beocenter 4000]