Beomaster 4000

16th June 2013

No FM reception with all other functions was the fault with this receiver. Faults in the tuner and IF sections of FM receivers are most easily tackled by first checking that the DC conditions around the relevant transistors are correct before getting to involved with the more complex aspects of the circuit, and it was soon found that voltage drop across resistor 63 (1.5k) was negligible and that only a very small voltage was present across resistor 66 (also 1.5k). These two measurements suggested that TR5 (BF194) was open circuit, and a replacement solved the problem. A BF240 or a BF494 make a good replacement for the BF194 in this circuit. The same basic FM stages are also used in the Beomaster 3000, 3000-2 and Beocenter 3500. [Beomaster 3000, Beomaster 3000-2, Beomaster 4000, Beocenter 3500]