19-12-2019, 11:33 AM
What model Blaupunkt 6v Car radio do you have, Trevor? It's possible that among my large collection of Blaupunkt Service manuals and diagrams, I may have one for your set, but I'd need to know the model name (usually it's a German Town or City) serial no., including the first letter, and, if possible, the part Number, which begins 76xxxxxxxxxxx. as the same model name was used over a number of years. Incidentally I'd have thought a 6v Radio more likely to date from the 60s than the 70s. FM not working is most likely due to a front-end fault, though there could be a problem in the ratio detector circuitry. Pretty well all modes used the same transistors in a common FM/AM I.F. strip, with the 465kHz and 10.7 Mhz I.F.Ts in series, so yjr problem is unlikely to be there. As with all such faults, checking the bandswitcing, then working back from the last I.F, injecting a 10.7Mhz. signal (if you have the means to do so) is the way to go. Maybe start by injecting a 10.7Mhz FM signal at the tuner's output, since, IMHO, the fault is unlikely to be in the I.F. strip.
