[murf]

Hi Guy's and gals,
Have a Hickok model 800 tube tester that has developed a problem.
One day it started lighting the line fuse lamp on the panel when in tube test mode and while pressing P4 test button.
Any other test buttons depressed and no light on the fuse lamp.
Removed it from the case and noticed the 83 tube had some black ash like substance floating around in the tube.
Think the problem could be just the tube, or did something cause the tube to go bad?
Do I dare try to test the tube in my other tester, or would I find the tube is shorted out and cause a problem with that tester as well?
Any idea's?
murf

[morzh]

A good tester has a short test that should be done before testing any tube.
If not sure, don't.

[Chuck Schwark]

Also, some high powered tubes that take a lot of filament/heater current
(rectifiers for one) will also make that bulb glimmer or show a little glow.

Be sure you let the tester warm up at least 5 mins. and be sure to set the line adjust correctly. Once a heavy current tube is warmed up, I always re-check the Line Adjust and tweek it if necessary before test.

Chuck

[murf]

I have heard that if you replace the 83 tube with an SS substitute, you will have to re-calibrate.
Is this true?
Some say only if you replace the 5y3 with a SS sub.
Others say if you replace the 83 with a SS sub.
Wish I could just find a tube and be done with it.
Anyone know who would have one of these 83 tubes?
Thanks and enjoy your weekend.
murf

[Eliot Ness]

Bob Dobush has them for $18 new and $11 used. Bob is a good guy to deal with too:

http://www.findatube.com/

[Chuck Schwark]

And, you can't sub the 83 rectifier, as it's a mercury-vapor type with different voltage drop
than a normal rectifier tube and the 800/800A testers are calibrated with this voltage drop.

Chuck

[Eliot Ness]

What's so confusing? You wanted a source for an 83 and I provided one. Chuck reinforced that you can't sub an 83 with a different rectifier because that tester is calibrated for the voltage drop of an 83.

The only way you'll know if that SS 83 replacement is "good enough" for you is to try it. Most people who pay the $$$ for a Hickok are shooting to be a little closer than just in the ballpark.

[murf]

Thanks for the info guy's.
I am going to check with Bob and see if he has a new one.
Thanks for the tip.
murf

[Alan Douglas]

You can't compare readings between two different testers.

[murf]

Good news,
Bob just got in a batch of 83 tubes.
So I will follow advice given and put in a new tube.
I did try the ss replacement, and it seemed to work fine.
But I think the tube will be more accurate according to what Chuck said.
Thanks again for all the help,
murf

[Radioroslyn]

Just for the heck of it you could measure the DC voltage from the filament to gnd on the SS83 and the MV83. That will get you an idea about the different readings of tested tubes.
Terry N3GTE

[K7Sparky]

Stuff that look trash inside Mercury Vapor rectifiers is not unusual.

BTW 83s are supposed to be mounted vertical. As far as I know Hickok mounted them all horizontal. Just picking nits.

When you get into ones the size of your upper arm that we used to use in adjustable speed DC drives they had a bunch in the bottom. The Mercury also can coat the inside of the bottle or something does. Never got to bust one to see. Might have started with 3B? Toooooo long ago.

[TA Forbes]

I'm late to this post, but from what I recall none of the "red case" Hickoks respond well to using a solid state substitute for the 83 tube. I will go back to some references and see if I can find more detail on this. 

I have maintained glass tubes in my 800A. However, I did successfully sub a solid state replacement for the 5U4 in my Precise 111, and after recalibration it does very well, especially when testing high-current-draw tubes. 

The Hickok 800 is a good tester but not a laboratory-quality tester, it is important to know that when testing tubes. 

[TV MAN]

I have a Hickok 600a that had the 83 replaced with regular diodes. I was all concerned about that, but other than a sticky meter, it works ok. Calibration voltage seems pretty close. May not be perfect, but does tell me if a tube is good or bad. They probably recalibrated it so that it works decent. I also have a Precise 111 that will has verified a tube if in doubt.

[Alan Douglas]

Removing the 83 reduces the power-transformer load by 15 watts, which has to be a good thing.  There may be some differences in Gm readings, but no Hickok is a laboratory instrument.  Once you get used to your particular tester's quirks, you're fine.

There's no problem running an 83 on its side. The plate voltage is just 150V, and it's only applied when you push the Gm button. The 83 has plenty of time to warm up.