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Help understanding a 89 radio rebuild new guy
#9

Hi Bruce and welcome,

Not to inundate you with more schematic info but https://philcoradio.com/library/download...%20146.pdf This has it all except the parts values on the diagram.

If all seems well up to the mixer (36 tube) connect the generator to the grid cap w/a 260kc signal that is modulated. If all is working you should be able to align the IF stage #'s 15, 19, 22, 26.

The next step I would do is measure the resistance from the cathode pin of the 36 to the junction of #'s 8 & 10 and the osc coil. Should be around 5 ohms. Anything much higher makes the osc coil feedback winding suspect. Pop it out and inspect it, the small winding near the bottom of the form. It may have hazy appearance but a little heat from a heat gun will clear it up it's wax. What you are looking for are green dots. This is rot in the copper wire caused by a chemical reaction. If so it's time to rewind.

>end up with a potted capacitor that did have a .09 uf value<.
You've probably already figured this out that some values are not available anymore. .09 is a .1 as is a .05 is a .047. There are many of resistor values that are discontinued. On these old sets the spec is 20% so there's a fair amount of latitude in value to find a modern replacement. It's tough on servicing tube type TV's.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
462ron - by 462ron - 09-01-2024, 08:49 AM
RE: Help understanding a 89 radio rebuild new guy - by Radioroslyn - 09-01-2024, 04:11 PM
462ron - by 462ron - 09-02-2024, 08:04 AM



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