Re: Quad FM3 no stereo
Here's another quirk. I was skeptical about the voltage of 14V being supplied to the decoder, so I put the FM3 regulator into Spice.
It is not self starting.
That is why there is a Mullard VDR (the red disc) across the -ve series pass transistor. Even a few hundred ohms there starts the regulator up. But depending on the resistance value you can get quite a range of output voltages - quite different on - and +.
Of course that is not how it would be done now - cheap LM317/337 regulators would do the trick nicely.
Craig
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