I have a Hickok 800k and I'm having a problem with the shorts test. It seems that at times the shorts lamp will light on any tube I test, on all the switch positions, even on new tubes. Sometimes I'll test a tube and it will light up the lamp in all the switch positions. I'll retest the next day and it won't have any shorts!
I was looking at the capacitor that connects to the shorts lamp. It is a .05uf, but it seems that the schematic calls for a 1uf capacitor. Could this be my problem?
Should the shorts lamp light up if I don't have a tube in a socket?
Any help would be appreciated.

Hi John

That cap you noticed may be leaky? In your tester there may be a resistor across the lamp to reduce sensitivity. The resistor could have gone higher in value?

The actual value of the cap isn't critical. A larger cap will light the neon bulb brighter when you have a short. If the short light lights even without a tube in the socket you have leakage between tester pins. Are you in a very high humidity area?

Norm

I have a Hickok 800k and I'm having a problem with the shorts test. It seems that at times the shorts lamp will light on any tube I test, on all the switch positions, even on new tubes. Sometimes I'll test a tube and it will light up the lamp in all the switch positions. I'll retest the next day and it won't have any shorts!
: I was looking at the capacitor that connects to the shorts lamp. It is a .05uf, but it seems that the schematic calls for a 1uf capacitor. Could this be my problem?
: Should the shorts lamp light up if I don't have a tube in a socket?
: Any help would be appreciated.

Hi Norm,
I just received the tester a couple weeks ago. I will try to open it up and let it air out for a few days. The plywood box may be holding humidity. When I turn the tester on, it may warm up and cause a humid condition. I'll also check the capacitor and the resistor. Would it be a good idea to spray the sockets with Deoxit?
Thanks, John

: Hi John

: That cap you noticed may be leaky? In your tester there may be a resistor across the lamp to reduce sensitivity. The resistor could have gone higher in value?

: The actual value of the cap isn't critical. A larger cap will light the neon bulb brighter when you have a short. If the short light lights even without a tube in the socket you have leakage between tester pins. Are you in a very high humidity area?

: Norm

:
: I have a Hickok 800k and I'm having a problem with the shorts test. It seems that at times the shorts lamp will light on any tube I test, on all the switch positions, even on new tubes. Sometimes I'll test a tube and it will light up the lamp in all the switch positions. I'll retest the next day and it won't have any shorts!
: : I was looking at the capacitor that connects to the shorts lamp. It is a .05uf, but it seems that the schematic calls for a 1uf capacitor. Could this be my problem?
: : Should the shorts lamp light up if I don't have a tube in a socket?
: : Any help would be appreciated.

Hi John

I would first inspect the components around the neon lamp and other places in the tester. Be sure the area is clean and dry. It doesn't take much moisture/leakage for a neon lamp to light.

Norm

: Hi Norm,
: I just received the tester a couple weeks ago. I will try to open it up and let it air out for a few days. The plywood box may be holding humidity. When I turn the tester on, it may warm up and cause a humid condition. I'll also check the capacitor and the resistor. Would it be a good idea to spray the sockets with Deoxit?
: Thanks, John

: : Hi John

: : That cap you noticed may be leaky? In your tester there may be a resistor across the lamp to reduce sensitivity. The resistor could have gone higher in value?

: : The actual value of the cap isn't critical. A larger cap will light the neon bulb brighter when you have a short. If the short light lights even without a tube in the socket you have leakage between tester pins. Are you in a very high humidity area?

: : Norm

: :
: : I have a Hickok 800k and I'm having a problem with the shorts test. It seems that at times the shorts lamp will light on any tube I test, on all the switch positions, even on new tubes. Sometimes I'll test a tube and it will light up the lamp in all the switch positions. I'll retest the next day and it won't have any shorts!
: : : I was looking at the capacitor that connects to the shorts lamp. It is a .05uf, but it seems that the schematic calls for a 1uf capacitor. Could this be my problem?
: : : Should the shorts lamp light up if I don't have a tube in a socket?
: : : Any help would be appreciated.

I suspect leakage in the sockets: try drying them out with a heat lamp, gun, or hair dryer. Some of my Hickoks show leakage like that during the summer.

My Hickok did almost the same thing and it proved to be one of the internal tubes in the tester that was bad.

: I have a Hickok 800k and I'm having a problem with the shorts test. It seems that at times the shorts lamp will light on any tube I test, on all the switch positions, even on new tubes. Sometimes I'll test a tube and it will light up the lamp in all the switch positions. I'll retest the next day and it won't have any shorts!
: I was looking at the capacitor that connects to the shorts lamp. It is a .05uf, but it seems that the schematic calls for a 1uf capacitor. Could this be my problem?
: Should the shorts lamp light up if I don't have a tube in a socket?
: Any help would be appreciated.

Thanks to all the fine people who gave me suggestions on my shorts lamp problem. It was the 83 tube. I replaced the tube today and that cured my problem.
I was surprised to see that the tube still checked OK. The inside of the tube appeared to have some metal flaking. I assume that was the problem.
An added benefit is that my tester got super clean while I was looking for a solution to my problem.
Thanks, John

: I have a Hickok 800k and I'm having a problem with the shorts test. It seems that at times the shorts lamp will light on any tube I test, on all the switch positions, even on new tubes. Sometimes I'll test a tube and it will light up the lamp in all the switch positions. I'll retest the next day and it won't have any shorts!
: I was looking at the capacitor that connects to the shorts lamp. It is a .05uf, but it seems that the schematic calls for a 1uf capacitor. Could this be my problem?
: Should the shorts lamp light up if I don't have a tube in a socket?
: Any help would be appreciated.