I am too lazy to trace the whole thing but am I correct to understand that the heaters use rectified voltage for heaters.....yeah I think I am as they are directly heated and use the filaments as cathodes so they are referenced to the common.....this is just....inconvenient.
Kirk! Do not get me any of these to restore.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Check post 8 !
The filament wanders back and forth that's why I drew it out so I could follow it with out getting ein Kopfschmerzen . My Russian is pretty good ! Yes the dc for the filament is derived from the B+ though a divider, 1800 ohms in series and 680 ohms in parallel with the voltage. This drops the 120vdc or so down to 9vdc. A 200mf (sorry don't know how many nf that is) is used to decouple the 9v from the hv.There are 6 1.5v tubes connected in series to equal 9v. String starts at the 680 ohm resistor and ends at the osc coil as the - return (a little odd).
Kirk! Do not get me any of these to restore.
Between Sam and I we have 3 of them!!!!
Terry
(This post was last modified: 05-27-2016, 10:15 AM by Radioroslyn.)
Yeah but only when the hamburger is within reach. I need to see the hamburger, smell the hamburger, taste the hamburger....a mere mentioning the hamburger does not affect me much
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Well for all you kats and kittens that are waiting with baited breath to hear what is happening with the 42-854 the resistor for the filament voltage divider came in the mail the other day. Had a little surprise as I thought I was get just 1 but got 3. So this afternoon I removed the old one and install the new. Thought I'd take a few pics before I power it up and it burst into flames! Also replaced a few pieces of rubber wire and broke the socket for the 1LB4. I think I can repair it, the center part pulled up though the socket and the cover popped off. Off to put the tube back and add some power/watch for smoke!
Terry
(This post was last modified: 05-30-2016, 06:35 PM by Radioroslyn.)
After I installed #56 still no joy! This getting a little ridiculous!!! Measured the current though the string and it was a little like 60ma. Hmmm. I replaced the 117Z6 w/a silicon diode which increased the voltage a little but didn't what I was hoping for. Went from 8.0v to 8.5v. Then I remembered that it did work before I replaced the caps in the IF and Mixer stages. So by looking at my hand drawn filament diagram (looking at the schematic will give you a headache) I zeroed in on #51 and that thing was shorted. It knocked 1.5v down to .5v. HA HA I found it!!!!!!!!!!. So now on to more troubleshooting now that all the tubes have the correct filament voltage. There is still some amiss as when I touch the ant post I got nothing.
Terry
(This post was last modified: 05-31-2016, 07:37 PM by Radioroslyn.)
This thing wants to fight me tooth and nail. Both audio stages are working but won't pass a rf signal. If I connect the gnd side of the generator to the chassis it modulates everything with 60cy hum. So I rigged up a gimmick cap ( some twisted hookup wire) to feed in a IF signal. Fed the 2nd IF amp tube plate w/ 455 signal and got a little output from the spkr. Tried the grid and get zip. Plate and sg voltages look ok so I guess it's onward to the 1500 ohm #50 filament return resistor. Come to think of it I should double check the filament voltage on the tube too.
They love pain!
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