Resetting the line adjust on a Hickok with Plate Current Flowing

Tubes Asylum

Questions about tubes and gear that glows. FAQ

OK--I had to try this. I had a 533 on the bench and set it up with an external meter monitoring the primary of the power transformer--so that I could tell what was happening.
First I tried pushing the P4 test button at the same time as the line adjust button. This caused the meter to deflect downward about a 1/4" but did not affect the reading on the external meter monitoring the primary of the tube tester's transformer--it stayed at about 95 VAC when set to line the normal way.
Next--I placed a 6L6 in the tester and tested it the normal way. The primary of the transformer was 95 volts when set to line, and the tube tested at 5200--which is right on the money.
Now I tried the line reset method. When I reset the line with the P4 test button depressed, the primary of the power transformer went up to 105 volts. With the line adjust set this way, the tube tested at 7000--which is WAY off the mark. It sure would make those weak tubes look better by testing them this way!
So based upon my 533 test (and this may not be the same for all Hickoks--but I'll bet it is):
(a) when you press both buttons at once you are not really setting the primary of the power transformer properly. And we KNOW the Hickok method for this was to add a meter at the transformer primary as in the 539C.
(b) when you reset the line with both buttons at once, the reading you obtain will be grossly high. A 6L6 went up nearly 2000 micromhos this way. It is obvious that a 6L6 should NOT read 7000 on a 533, as the nominal value printed on the chart is 5000.
So--best use the tester as designed. I have to admit that I had not tried pressing the P4 and Line adjust at the same time, and you do get a reading on the meter. Problem is you are obviously not reading the right thing, and need to add additional meters to do this line reset thing--just like they did on the 539.

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion

Topic - Resetting the line adjust on a Hickok with Plate Current Flowing - Chris Haedt 05:07:28 09/04/03 (3)

Re: Resetting the line adjust on a Hickok with Plate Current Flowing - Steve O 21:26:01 09/04/03 (2)

Re: Resetting the line adjust on a Hickok with Plate Current Flowing - Chris Haedt 04:49:35 09/05/03 (0)

Re: Resetting the line adjust on a Hickok with Plate Current Flowing - Chris Haedt 04:22:05 09/05/03 (0)

You can not post to an archived thread.