The "calibration manual" does not exist. Apparently with no copyright issues. There is no evidence that Hickok ever supplied any other "special" or "additional" info to the FAA, government or anyone else. If you can follow the proceedure for a or a a or b series calibration then you can figure it out on your own. There is little reason to fiddle with the guts unless you have replaced the 83 and or 5Y3 with a poor balanced-sides tubes.
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The "calibration manual" does not exist. Apparently with no copyright issues. There is no evidence that Hickok ever supplied any other "special" or "additional" info to the FAA, government or anyone else. If you can follow the proceedure for a or a a or b series calibration then you can figure it out on your own.
There is little reason to fiddle with the guts unless you have replaced the 83 and or 5Y3 with a poor balanced-sides tubes.
The allows one to adjust the amplitude of mismatched hz pulses the series also allows the adjustment for the 5Y3 which DOES affect the gm reading by adding to the plate current and for the 5Y3 by adding to the grid signal offset.
BUT, if you have a well ballanced tube to begin with, the issue is minimum. If you have plate, screen, 40 bias per or any Hickok calibration instruction, then leave it alone! If you have a digital meter you MUST add the right amount of resistance across your probe tips or you will read the plate and screen wrong your plate might read when it is really The dual pot is 9 of 10 times worn out and or grimmy and repairing one is close to brain surgery, not to mention poor on accuracy the day it was made.
Done to many, I know what I speak. In fact, put deoxit in the next room with your stereo and away from test gear. It IS conductive oil and creates tiny leakage circuits a tester will pick up an a bad tube. Last, everyone thinks tinkering with these will make it digital age accurate.
It will not. They were never intended to decide if an eBay seller is ripping you off by claiming his tube reads points higher than you tester says. This is NOT rocket science. USE an isolation transformer, that is a must. Study and understand before you begin. Google, BAMA, and a host of others have all the info you need, so go seek it or mail the tester off.
I assume your comment is experience based. But if you put it on, you can NOT remove it Take a clean piece of plastic, make sure it tests as infinite resistance. Spray Deoxit. Let dry. Measure resistance again. In general there are very few adjustments that can be made in most of these tester, for the the two primary adjustments would be R5 for the line voltage and R20 which adjusts the 83 tube balance.
The also allows you to adjust the balance for the 5Y3 tube, so it would be important to have a closely balanced 5Y3 tube in the This was mentioned in the previous post. Also check the signal voltages are correct as noted on page 3 of the manual. Use a standard high impedance meter for the signal voltages. I do not want to wait minutes to allow the 83 tube to warm up each time I check a tube, and there should be no issues with drift or changes over time.
You should be able to get the proper line voltage and plate voltage with the SS replacement noted in the posting, you can always adjust the Zener diodes as needed to dial in the correct plate voltage. A few extra volts on the plate has an unmeasurable effect on GM. I also recommend using an external variac to set the line voltage and avoid the line sag issues with the internal rheostat. This has more to do with issues of maintaining the proper grid signal and heater voltage under testing, this was also recommended by Alltubetesters.
The military Hickok TV manual is informative from a trouble shooting procedure and calibration instructions, although the has far fewer adjustments. Not exactly accurate. When used correctly it should first be used as a cleaner, wiped away and then very lightly reapplied as a switch lubricant and anti-oxidizer.
The problem arrises when people just squirt some of it out of either a can or hypo and then just leave it. I thought I had saved it some time ago. And I did, but it was on a backup disc that I forgot about from an older computer. The voltages are identical on almost all of their tube based Mutual Conductance testers. As is common with most aged components, they will drift in value thus the voltages will change also.
The 5Y3 and 83 tubes are no exception to the aging process if used. I am of the opinion that one of the very first steps to check for proper calibration should be strong and balanced sections in both. One of the main causes of a weak and unbalanced tube would be from excessive use or, hours of use.
Calibrating to low value unbalanced tubes would only result in out of tolerance voltage readings and cause a false sense of accuracy under an actual load.
Hickok schematics are, at best, difficult to follow without the desire and time to understand them. Most of the users simply want to know that it is safe to use a tube in their audio equipment. For many of these folks, a calibration procedure for their exact tester would save them hours of time. Lots of free procedures out there on B. I have read many conversations about the use of Deoxit or contact cleaners to clean the phenolic wafer switches.
When you think about what you are cleaning from the switches is an oxidized form of the actual metal the contacts are made of, this makes for a better understanding. If you spray cleaners, especially oil based, all over the surface area of the switch, you impregnate the aged phenolic with the oxidized metal, or oil, causing small amounts of conductance to other contacts that could indeed give inaccurate readings, especially during leakage testing. Properly cleaning the contacts requires much time and patience to assure the phenolic does not get wet with the contaminents and must be removed with care.
This is the last reply for me on this. YOU are kidding yourself. I suggest that you actually spray or slather it on the switch wafers and then test for a shorts and leakage and see what happens.
The real test is here is to verify what I state as being true or false. A scope is the only real way to find a tube with equal or near equal peaks.. All times are GMT. The time now is PM. Page 2 of 6.
Hickok Model 752A Tube Tester with manuals, scrolls and extras
I am not saying that you should not purchase a Hickok like a or at the right price and condition, however in the absence of other considerations, these are good choices. Model A. This is the best of the basic early testers. Data is available. Has sockets up to 9-pin mini. No 9 or 12 pin compactron.
Hickok 752/A Tube Tester Calibration Procedure Test Data & Owners Manual CDrom
The and A have identical circuits and the only difference between the two is the A has the modern tube sockets added so no CA-4 or CA-5 adapter is required. The information on this disk is pertinent to both models. On this CDrom are 10 files in. Adobe reader is required and is a free download from Adobe.