Zenith 7h822-z tubes not lit

[init4fun]

Originally Posted by Tennangler

Someone gave me this radio to try to get working. The bulb on my DBT did not light when plugged in. The Pilot light is on but none of the tubes light.
Can someone tell me the first thing I should check?
Thanks
James

This is a 7 tube series string set, with a neon light for a pilot light. Your first check will be a continuity check of all seven tube's heater pins, and it's VERY highly likely that you've got at least one tube with an open heater.

It's also highly likely that at least the electrolytic B+ filter cap(s) are gonna need replacing, along with any wax paper caps


Here is a link to the schematic, click on the little eyeball icon next to the icon of an old time floppy disk to view the pages. I see no pilot light in this schematic, but then this lists as 7H822 only, and not 7H822-z, perhaps the "z" designation was the model that includes the pilot light. I do have several variants of this type of Zenith and the pilot light is always a neon type. With no tube rectifier, that traditionally had a heater tap for driving a standard #47 incandescent (Such as the 35W4 rectifier tube did) it was easier for Zenith to use the neon pilot light (it and a resistor provided direct 120 V operation) VS attempting to derive the 6 V needed for a type 47 bulb in some other way.


http://www.nostalgiaair.org/resources/309/M0025309.htm