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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Better yet, use an appropriate solid state tube replacement. If C3 were not used, the physical inertia of the meter movement would perform the same function. A word on the transconductance measuring circuitry for those who might be interested. However, I can find no one offering calibration tubes on the internet who addresses or even seems to be aware of this potential problem. It would then read directly ma. For triodes, mu mahual almost completely a function of the tube geometry and is essentially constant, as it almost is for pentodes except at very low plate voltagesunlike transconductance and plate resistance, which may change significantly.
Accurate Calibration Of The Hickok 539B And Hickok 539C Tube Tester
Learn More – opens in a new window or tab Any international shipping and import charges are paid in part to Pitney Bowes Inc. I have been interested in electronics initially tube electronics since the uickok grade.
Learn More – opens in a new window or tab. In terms of accuracy, this change turned out to be the second most important change after changing the transconductance measuring circuit resistance values and using the corrected calibration values. Method 2 Set up for testing a 6L6 53b9 using the roll chart values and put a known good 6L6 tube in the octal socket.
I think it is pretty well accepted that most tube Hickok tube testers do a majual good job at this, irregardless of exactly what the plate voltage they actually use in order to do gickok. For the 5Y3 solid state replacement, the values of the resistors are not critical. Although it is not possible to prove or disprove it, I strongly suspect that the Hickok technician or engineer that made these roll chart set-up values probably, and mistakenly, was thinking along these lines.
Check at the junctions of:.
This is situation is discussed along with possible options in the next two sections. 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 Whenever one makes a measurement, whether it is using a tube tester or just reading a tape measure, there hckok always be a limit to the accuracy involved and thus some associated error.
Most tube testers will probably not test close to the operating temperature the tube will experience when actually in use either.
I make no apologies for manuap and I have tried to make clear what was opinion and what was not and to make clear why I espouse those opinions. So, in general, as long as a given tubes transconductance value lies roughly in the normal range, it should work well in most applications.
Again, you may have to compromise to some extent. This tube tester is designed so that the user cannot inadvertently connect two test voltage sources to the same device under test DUT pins and thus to each other, e.
This is not included in any of the usual calibrations procedures, and it is probable that the original Hickok engineers never even suspected that there was a problem, but if you want to be able to test higher current tubes while retaining good accuracy, you should make this simple modification. You may find that your meter is less sensitive than the Hickok specifications, i.
I think that this serendipitous effect is significant in Hickok testers, because there are several potentially significant errors in the design and calibration of these sets, but even so, Hickok testers, in general, seem to still be fairly accurate in practice.
On both computer simulation and on the actual set, I could find no set of values that would allow highly accurate measurements, i.
Douglas on the Antique Radio Forums site and he acknowledged that that statement was an error in his book. Shunt circuits like this have the property that when the shunting resistance is high and the degree of shunting is small, most of the current goes through whatever is being shunted and only a little through the shunt and so the shunt has relatively little effect.
Assuming that the values of the remaining resistors are correct, then the output voltages should be correctly calibrated as well.
Put the negative lead of the voltmeter to the post of R16 3 Hlckok pot. Note that using the above solid state replacements significantly reduces the heat build up in the confined and non ventilated spaces of the set 25 Watts, altogethera definite benefit, but also reduces the load on the power transformers.
Hickok B Tube Tester Instruction Manual & Tube Data | eBay
Thus changes or inaccuracies in the shunt have little effect. In this modified emissions method, more of the current goes to the plate, which is designed to handle higher currents, and less to the grids, which are not designed to carry much current.
hickkk Learn more – opens in new window or tab. Set up the tester for testing a 6L6 tube and put in a known good, non gassy 6L6 tube. This amounts to causing the reading to always be micromho too large.