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GE H-632U Ballast Resistor Hytron K42B
#1

Not sure where this should GO.. So if in wrong place please move...


Ballast resistor. Hytron K42B.. I am sure this has been asked already But cannot find a schematic or Pinout of that tube.. With Resistance Values..

This is in a GE H632U Radio that I am starting to work on.. schematic for radio shows 2 resistors in series with the pilot lamp across one of them..

I tried to measure the tube and from pin 3 to 7 I get approx 3.0 Meg and from Pin 7 to 8 I get approx 770K.. No readings on any other pins..

Is this correct??

Skip..
#2

Hi Skip,
> But cannot find a schematic 
It's R-14 and it's kaput. As you can see it lowers the 120vac to power the heater string and dial lamp. So there are a couple ways to replace it.
1. Try to find a repl;acement tube.
2. Use a non polarized cap ( generally about 6-8mfd @ 200v).
3 Use a resistor to equal R-14.


So R-14= 133 ohms @ 25w  & a 40 ohm resistor in parallel with the lamp so it will equal 300ma. R-14 will get very hot and is pretty big too.
Or this:


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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
#3

If it were me, I would probably go with the capacitive dropper, higher value non polarized capacitors are smaller, cheaper, and easier to find then they used to be. However you will still need a resistor to parallel with the pilot lamp.
Regards
Arran
#4

Arran, Ok What would that circuit look like?

Skip...
#5

Same as mine but remove the diode and 33 ohm resistor. In it's place add a 8.5 uf non polarized cap at 250wv.

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
#6

Terry, OK thanks.. in your opinion what would be the best one to use.

Skip...
#7

Doesn't matter much. Both do the same thing. My thinking is that you may have the two resistors and can wire it up pretty quickly. The capaciitive dropper you got to order and wait for the part to come in. Resistive dropper will generate a little heat (a lot less than a flaming hot BL42 tube) vs the cap won't. The 33ohm resistor you can play w/the value a bit something like 25-40 ohms will work. Either one you can wire up into an old octal socket to make in plug in like the original.

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
#8

Well I broke down and order some Caps and found a new ballast resistor.. So ordered that also..

Arrived today.. Measured pin 3-7 got 134 Ohms.. Then measured 7-8 and got 23 ohms.. So that looks reasonable.. What do you guys think?


Skip...
#9

What's there to think....? It's a ballast tube.

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.




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