05-06-2017, 04:05 PM
(05-06-2017, 03:24 PM)pwdrive Wrote: What they should have said is that two of the cathodes share a common connection, there's three cathodes in the valve, each one heated by its own heater, the three separate heaters are series connected in the valve.
Two of the cathodes have to share a common connection because there are only 9 pins available in total for all the electrodes and heaters.
The way the valve is graphically represented in the Philips valve data sheet sums it all up.
The audio output is via the tertiery winding and R20/R22.
Lawrence.
O.K. thanks. I just accessed the schematic online. I was relying on memory so confusing matters. L23, L24 and L25 is where we're at in the discriminator circuit. R20 and R22 I can see. I think I'd meant C44 so will finish off tonight. The link is here as a refresher for anyone who wants to see the circuit. You can see there the 3 cathodes. Any comments on the FM circuit welcome - it uses variometers. vorkreisvariometer was a word I had some difficulty finding even on line at the time.
Pardon the earlier confusion over the capacitor.
http://85.144.220.212/nvhr/RFT_5170.pdf
