Re: Grundig Satellit 2000
cruisinradio,
Thank you for pointing that out. I checked the voltages across ST1 and R303 and these look correct. However there was no oscillation at the junction of coil (A) and C308/C310 as there usually would be when the circuit is working, so something in that part of the circuit is evidently intermittent. Do varicap diodes have an intermittent mode of failure? If not, then that means it could be the transistor or one of the surrounding ceramic caps.
There is one black cap in the tuner section, a 47n square cap (C320?) which I think has a plastic case. As can be seen from the photo, all the other caps are small ceramic types and although there is one with a black dot on top, none are actually black bodied. Also, there are no black bodied caps in the FM IF section.
There are, however, a number of black bodied ceramic caps dotted about the AM circuits but all of the AM bands are working at present. If those caps are problematic then they might be worth replacing as a pro-active measure, but I will have a look at that once I have sorted this FM band problem.
I think I might have a go at re-flowing the joints around T2 and surrounding components on the tuner board first which I should be able to do without removing the board. If that doesn't solve it, then I guess it would indicate an intermittent component somewhere.
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