bench test chassis with a HV probe?

pinnut

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ive got a neotec chassis from a maximum force that is dead, no HV at all. i dont have the tube to test it in. im going to replace the little power IC to see if that brings it back to life. could i test it with an HV probe on the anode, and the probe lead clipped to the chassis, just to see if the HV comes up?

thanks
 
never a safe thing that i would do nor recommend but i have read people doing it. that is probably a 2515C chassis and they are very common for bad caps and flybacks drifting out of focus or they die.
 
Please don't do this.

But if you do, at least put the anode cup in a glass jar and keep you and everything else far away from it. (Other than the probe I guess.)

Please remember that in the range of 25,000 volts, electricity can jump pretty far.
 
Back when I did lots of monitors I used to test them without a tube
all the time if I didn't have a compatible tube (they came off route locations).

You need to have a compatible yoke coil connected or once you repair the
HV section it will blow near if not instantly.

I isolate the anode cap (a glass jar as the previous poster noted) works fine.

You don't need an HV probe. You need to measure your B+. If your B+ is too
high you'll be in shutdown and get no HV anyway.

I would hang a small cotton string next to the flyback and use alligator clips to
connect the meter to test the B+.

You can't leave it powered on long without a tube. If the HV section is working
then A) You will read proper B+ and B) the high voltage transformer will pull the
string over to it like a magnet.

It's down and dirty but it works.

If no HV on an older Neotec, assume the orange drop caps, the horizontal output
transistor and of course the flyback. There is also a small high voltage cap right next
to the horizontal output that sometimes blows.

JD
 
Wouldn't it be best/safest to use any random (maybe one with bad guns) tube ?

Ground the dag, connect the anode cap, and it will just act as an HV capacitor (like a real tube would). You just wouldn't be firing electrons at the anode.

Almost surprised a 'bench test' 'load' wasn't created for this purpose.... a glass tube (like a 6? inch length around four inches diameter, with a vacuum of course. Have it have an anode cap on one end, and a ground connection with alligator clip on the other end.
 
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