Download HICKOK B TRANSCONDUCTANCE TUBE TESTER service manual & repair info for electronics experts. Daniel Schoo produced a classic document on calibrating a Hickok B/C tube tester which was published in on AudioXpress. Hickok B/C Mutual Conductance Tube Tester – Checkout and Calibration. Version Use this procedure to test and calibrate the Hickok Model C mutual .
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Connect the meter to the plate current posts and remove the shorting link. If the replacement meter movement is more sensitive than the original, it may be possible to hicjok a combination of series and parallel resistors to achieve the same electrical characteristics as the original meter.
Manhal point here is that, in my opinion, it is a waste of time and money and effort to even use a calibration tube when a better, less expensive, and more accurate alternative is readily available.
Second, the grid bias voltage is actually a series of half waves of a 60 cycle sine wave which means it goes from 0 V to It is perfect for checking the 539v of your calibration on any brand of tester as well. Most of these would not would apply for a tube tester or for a curve tracer, as both evaluate a tube as if it were being used in simple, single-ended i.
Put the negative lead of the voltmeter to the post of R16 3 K pot. Without going into the details, there are several possible circuit configurations that actually make the set harder to calibrate and potentially less accurate.
Type 83 Solid State Replacement. Just setting the tester on an angled surface will often be enough to require re-adjustment of one or more of the meters. An 18 ohm 2 W resistor worked in my set. 5399b a concrete example, consider an experiment measuring the transconductance of a 6L6GB tube as measured on a Hickok B mine, actually, but long before the modifications and before even very accurate calibrationwhere the transconductance measured about Micromho in the C range and Micromho on the D range, a difference of about 5.
See terms – opens in a new window or tab. Such statements are usually associated with someone who would like to sell you an expensive tube, tube tester, or related merchandise. Remove the scope when done. In actual practice, there are several reasons why a curve tracer can be less accurate than the tube tester.
This simple method is based on the fact that the transconductance at any point is just the slope of a line tangent to the characteristics curve at that point.
Hickom the positive lead to the center post of R This issue is greatly exaggerated and the effect, if any, is generally small enough to ignore, especially in multi grid hiickok such as pentodes and tetrodes. Therefore, the voltage drop across the meter should be 0. First, a little theory: Set up the tester for testing a 6L6 tube and put in a known good, non gassy 6L6 tube.
Remove the 83 tube or its SS equivalent and turn the function switch to A. If the bias voltage were doubled to -2 volts, the error part of the bias signal would then be 10 mv. Suppose in the example given in the last section that instead of a real tube that we had a magical tube that had a truly constant transconductance value of Micromho and that we got the above measurements.
If you plan on doing any kind of work on it you should know how to work around potentially lethal voltages.
Hickok B Tube Tester Instruction Manual & Tube Data | eBay
In practice, some ranges may be closer to zero than others. Sell now – Have one to sell? I have experience in design and maintenance engineering and with analog and digital devices. One is to make the meter read correctly for these ranges. Change the physical 539bb of the tester and hence of the metersand you will usually have to change this adjustment also.
Most manusl your set is going to be slightly different from mine, so some of the information here may be incorrect for your set! To get any reasonable accuracy, one would have to work out a correction factor for each tube type and each set of operating conditions. This is easily dealt with by adding an appropriately sized resistor in series with the main transformer primary winding. Some of the sub-assemblies appear to be different, also. Most tube testers operate manua, lower plate and screen grid voltages than in most actual applications.
Accurate Calibration Of The Hickok 539B And Hickok 539C Tube Tester
Packaging should be the same as what is found in a retail store, unless the item is handmade or was packaged by the manufacturer in non-retail packaging, such as an unprinted box or plastic hicko. If it reads too low, you might be able to correct this by taking the meter apart, if there is an internal series resistor, for example but this option is not recommended. The difference seems to be that in one case there is some expensive merchandise involved.
It is missing the meters, the roll chart, some of the precision resistors etc. The reasoning is this: There are 6 transconductance ranges and to accurately calibrate all 6, it would require 6 separate non-interacting zero adjustments and 6 non-interacting gain adjustments.
Accurate Calibration Of The Hickok B And Hickok C Tube Tester
See the Controversial Comments SectionNo. Nickok point about errors: If you have to change the value of R17 by very much, you may want to re-check the 40 V range as you may have to re-adjust R18 slightly. This would have an unpredictable but, in general, sizable effect on the transconductance measurement just by itself. What the sensor circuit really measures is not the difference in the peak values amplitudebut something related to it. A word on hjckok transconductance measuring circuitry for those who might be interested.
One consequence of jickok method is, for example, that if the positive and negative half cycles in the original waveforms were asymmetric enough, there could be a significant offset in the transconductance readings even if the amplitudes of the voltage peaks were exactly the same. Note that the second and third arguments are actually very weak with respect to tube matchingsince accuracy is not the important factor. Schematic diagrams for both the B and C are readily available for free on the internet.