On Sun, Jan 6, 2019 at 6:38 PM fabry891 <fabrizio.vita80@gmail.com> wrote: > > >9VAC can be measured only between the two AC pins, that supply is just > >a floating (i.e. not connected to ground) transformer secondary. > > if I measure AC voltage between two AC pin the voltage is 10.5V. that is correct for an old C64/VIC-20 power supply. In many countries they were calculated for 220V input, but now all EU has 230V AC line voltage, so about 9V goes to about 11V on the secondary. > > >6561 are very expensive and by the way, are you only trying via a RF > >modulator to a TV? RF modulators easily go out of tune and can produce > >a way off sound carrier or transmit out of frequency between two > >channels too. Your TV might be trying to autotune (and might also fail > >at correctly auto-tune) or might even not try to tune to the correct > >channel. > >You can't conclude anything without trying how the audio sound > >directly at the A/V connector. > >PS: 6561 don't need to be programmed. > > I tried to connect audio/video VIC20 to tv with either RF modulator either > Scart cable that I made connect the pin 3 of VIC 20 audio to pin 6 of scart > connector, with the same result. Try to change C11 (I'm assuming you have a VIC-20CR, the one with 2 x 6116 SRAMs and 3 x 2114 SRAMs) On the old VIC-20, the one with all 2114 SRAMs, it's labeled C16. If this doesn't solve the problem, then try changing Q1 (new VIC-20CR) or Q5 (old VIC-20). But you should first check that the transistor is really bad or if it's just a failed connection or polarization resistor etc... (most of the checks can be done with a simple multimeter). Frank IZ8DWFReceived on 2019-01-06 21:00:08
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