clearing G1 Shorts

[ctc17]

Ohh Timmmmmmy, Relax! Cant you handle a shout out? a name drop?

[timmy]

lololololol...................................

[Username1]

I agree with Marty you should try turning the tube an all directions and try zapping it. But I think an hour or so with a good bright light, and carefully inspect the neck of the tube to see if there is anything visible as far as a shorting item goes..... Use an ohm meter too, check it to see if its short at 0v. operating voltage, or does it short only on full operating voltages. And at last resorts don't forget to remove the socket if the short is there at 0v. It could be a mechanical short outside the glass envelope.
I don't think I would do the 3,0000uf cap at 400V, you could weld with that much current. I would offer this: Tap the end of the tube, tap it harder, possibly vibrate it with a cell phone motor on the tube neck. And turn the tube, put the bad gun top, bottom. But I would still keep the gun horizontal, not lay the tube face up or down.
But that is just me. I got a lot of tubes going again with heating the tube, and wacking it good with a screw driver. Just don't break it, I bet you will run the possibility of making progress fixing this as long as you take your time and think it out.

[DaveWM]

roger all the ideas, currently the set is back with the owner, I am waiting to see when he can bring it back. I wonder if moving it may have caused something to break loose?

[bandersen]

I was fighting with a stubborn G1 short over the weekend. The basic 'clear G1 short' function on my CR70 just wasn't clearing it out.
So, I re-read the full manual and discovered there's an 'Extended G1 Short Removal Procedure' ! It's not even mention in the abbreviated manual inside the lid.

You can download the relevant pages here: http://www.bobandersen.com/images/sc...G1%20Short.pdf

The basic idea is you disconnect G2 to reduce the chance of damage, heat up the short using 'Manual Restore 2' and blast it with 'Clear G1 Short' before it cools down.

Good luck - it worked for me

[DaveWM]

I am going to print that out and keep in in the case.

[mstaton]

Bob, should we be expecting a video on clearing the g1 short?

[bandersen]

Originally Posted by mstaton

Bob, should we be expecting a video on clearing the g1 short?

Maybe. I'll see what I can put together.

[julianburke]

Unless you have a direct heater to cathode short of which a isolation transformer will cure, other type shorts are usually a minute speck of debris lodged in the gun assembly somewhere. Many times you can clear a short of this type by using a tesla coil "sparker" by running it around the pins on the base. In rebuilding tubes you would normally do this if a tube was showing signs of internal arcing due to impurities. (Not a continuous arcing, just a flash every now and then) Try sparking the pins and see if this will work. These types of tesla coil hand sparkers are normally used in vacuum work to look for leaks. This same type of device is also found in 1930-40's medical cases that had ultra violet tubes of various sizes to rub on your skin. If you have access to one, just stick a wire in there and run it around the pins.