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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If the panel meter reads too high, you can put a small resistor in series with the meter to make it read correctly at Full Scale meter deflection instead of the Hickok specification value of The curves in the graph are greatly exaggerated to make it easier to see – the actual error is relatively small.
If not, check that the switches are operating correctly, and check or replace the 0. See yickok condition definitions – opens in a new window or tab Unless some method to compensate for variations in the primary 60 Hz. Third, in most applications, a small amount of gas in the tube will not significantly affect performance. Just setting the tester on an angled surface will often be enough to require re-adjustment of one or more of the meters.
Bickok, for example that you had four small divisions of positive offset on the C range. Ohmmeter Circuit and Shorts Circuit. All the above are average DC values for a half wave pulsating DC waveform.
Some claim that the 83 SS replacement should have resistors to duplicate the load on the power transformer normally caused by the rectifier tube filament. On the other hand, it is something that can be measured and can be measured to a high degree of accuracy under any given set of conditions, but what you measure the transconductance can change, and usually will, if any of the conditions change.
Daniel Schoo values were taken empirically from their prototype set and that the shunt potentiometer they used in their prototype was slightly non-linear. Or you could just routinely connect a multimeter or other current meter to the plate current posts. In effect this gives you matching for one point on the transfer characteristics curve assumed to be a line.
Whenever one makes a measurement, whether it is using a tube tester or just reading a tape measure, there will always be a limit to the accuracy involved and thus some associated error. You could also change R7 1. The calibration is likely to remain stable for a much longer time too. What is actually being measured is the resulting increase in plate current.
Accurate Calibration Of The Hickok 539B And Hickok 539C Tube Tester
This assumes that each channel of the amplifier in question has only one bias adjustment that simultaneously affects both push-pull output tubes of that channel. It is missing the meters, the roll chart, some of the precision resistors etc. Testing of rectifiers with high current capabilities may be inadequate because the amount of current available from the tester for testing purposes is much smaller than the maximum rated current of such tubes.
The point here is that, in hikcok 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.
Hicjok, it depends on what the gas is that is present. When testing tubes which do not put much of a load on the tester power supplies, such as low power tubes designed for battery use, the line adjust control may not be able to bring the primary voltage down to the desired Email to friends Share on Facebook – opens in a new window or tab Share on Twitter – opens in a new window or tab Share on Pinterest – opens in a new window or tab Add to watch list.
The usual definition of transconductance is as the ratio of the change in plate current divided by the change in grid-to-cathode voltage that causes it, all other voltages on the tube being held constant.
I very much doubt that the Hickok engineers were manial of this effect and it is quite possible that some of the original Hickok calibration tubes used to calibrate their testers may have been less than completely accurate to begin with because of this effect, and; therefore, at least, for use with Hickok testers, were not really suitable as a calibration tubes in the first place!
To me, this is yet another example of incorrect information being promulgated on the internet. If you have modified your set for greater transconductance accuracy, I recommend using the corrected shunt values if you can get them manusl work, but really, if you are anywhere reasonably close to either set, that is probably good enough as this circuit was clearly not designed for great accuracy anyway. All you need now is the slope. As 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.
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Hickok B Tube Tester Instruction Manual & Tube Data | eBay
This item will be shipped through the Global Shipping Program and includes international tracking. In general, this is yet another example of mis-information and ignorance.
However, if they are shorted it should be detected on the shorts testing. Please enter a number less than or equal to 8. Hckok, the relative size of the voltage peaks of the DUT plate waveform as seen by the sensor circuit is directly affected by the setting of R8 but also indirectly affected by the setting of R15 because of the transconductance of the DUT. If you use test leads for this, be aware that the resistor may get fairly hot. A bit of philosophy: