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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Delivery time is estimated using our proprietary method which is based on the buyer’s proximity to the item location, the shipping service selected, the seller’s shipping history, and other factors. Putting the pass transistor within the bridge rectifier insures that each half cycle is treated the same This is important for the Hickok transconductance measuring circuitry and allows a DC device, a bipolar junction transistor, to be used in a AC application.
Accurate Calibration Of The Hickok B And Hickok C Tube Tester
Also, a goodly number of them just happen to sell calibration tubes or calibration services or have calibration devices for sale. Main Meter Voltage Conversion. The manuwl of transconductance assumes that pure DC is applied to the plate and the various grids of the DUT with a small AC signal superimposed on the DC bias voltage of the control grid. 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.
This calibration method results in a calibration line that is exact janual only for the C range at the point of the transconductance value of the calibration tube but becomes increasingly inaccurate as you get farther away from that point in either direction and for some other calibration hicko, the point where it was exactly correct would be different from the first tube unless both calibration tubes just happened to have exactly the same transconductance values.
When you re-tighten it, be careful not to over-tighten it or you could damage it. If the tube you are trying to match is non-linear at testing conditions that normally should be linear for that tube manuak, then it is likely to cause distortion in the actual application and should not be used anyway even if you can find another tube that is similarly matched at those conditions.
In this circuit the transconductance measuring circuitRcalibr is 10, ohms and Rload is generally around ohms if it uses diodes only. Remove the 83 tube or its SS equivalent and turn the function switch to A. If the leakage is greater than that corresponding to a Kohm resistor, it will light the neon bulb on the 1 to 4 SHORTS switch settings anyway and the tube would be discarded, so accuracy around 0 ohms is unimportant.
An 18 ohm 2 W resistor worked in my set. If you use the MAIN METER itself to adjust for zero, make sure that it is oriented in the usual position top away from the center of the earth and that it has been correctly mechanically zeroed prior to this. But only if Rload is quite small compared to Rcalibr.
Hickok B Tube Tester Instruction Manual & Tube Data | eBay
Most tube testers do not use excessively high voltages and the obvious reason is simply that there is no good reason to do so or to justify the extra expense that would be involved. If you have to compromise, compromise in favor of the P1 and P3 ranges. Note that this test is hugely more sensitive than is usually necessary, or, in general, even desirable.
Therefore, the voltage drop across the meter should be 0. For additional information, see the Global Shipping Program terms and conditions – opens in a new window or tab This amount includes applicable customs duties, taxes, brokerage and other fees.
I have experience in design and maintenance engineering and with analog and digital devices. This behavior merely reflects the fact that even tubes that are designed to be as linear as possible never are completely linear and many, if not most, are actually quite non-linear.
I will call this resistor R0 for reference purposes. In fact, this method could be used to accurately calibrate just about any tester, but it would be a bit cumbersome and inconvenient.
If you use test leads for this, be aware that the resistor may get fairly hot. It has been recommended that this be replaced with a non-conducting strain relief. This will make the maximum plate voltage slightly higher, but otherwise will have no significant effect. This can usually be ignored and becomes significant and highly variable at very low plate voltages.
Third, as usual for this set, changing the resistor values to improve the transconductance accuracy affects changes something else, in this case, the hixkok measuring circuits, so if you have modified your set, you may have considerable difficulty getting the emissions circuits to behave well.
Mouse over to Zoom – Click to enlarge. Even for regular power diodes, the applied voltage is fairly small 35 VAC max.
Accurate Calibration Of The Hickok 539B And Hickok 539C Tube Tester
However after extensive work with the simulations, I did eventually find a set of resistor values as given above, that significantly theoretically improve the accuracy in the transconductance sensing circuitry without requiring excessive changes. To me, this is yet another example of incorrect information being promulgated on the internet.
Measure the resistance between terminals M and J, and between terminals P and N. A 18 ohm 2 watt resistor, for example, did the job in my set. Better yet, use an appropriate solid state tube replacement. This tube would never be used as an amplifier at these operating conditions as the distortion would be excessive. However, having a calibration tube can be handy as it is a good quick way of hickik sure your tester is still functioning correctly i.
You should measure 40 V to just slightly above. If the panel meter reads too high, you can put a small resistor hickik series with the meter to make it read correctly at If these two variables were related in a strictly linear manner, hikcok would mean that if you were to graph them, it would be a straight line. If you are interested in mu, a curve tracer is probably the fastest and easiest way if just you happen to have one available. This could be a significant factor in the variability seen between measurements made with different Hickok and other testers.
Manua, is because other manufacturers and even other models from the same manufacturer will be testing under different operating conditions different plate and screen voltages, different control grid bias, 5539b ac signal control grid voltage, and probably slightly different filament voltage.
Put a 1 Megohm resistor from pin 3 to pin 8 on the octal socket. A curve manuaal, by its nature, tests tubes at hickoi variety of operating conditions, potentially including the plate currents and voltages that duplicate those of the desired application, whereas a tube tester generally only tests at one set of operating conditions, and usually at lower voltages than are used in many applications.
Now, at this point the tubes may be closely enough matched for most applications, hicook if even closer matching is desired, further matching can be based on having transconductance values as close to the same for the matched tubes as possible at the desired plate current. Running a very, very distant third, fourth, and fifth is using a tube hixkok. The miniature and sub-miniature tubes use very close spacing between the tube elements. This seems unlikely, but still might be possible.
This is another small source of error. Read more about the condition. 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 bag.
If the bias voltage were doubled to -2 volts, the error part of the bias signal would then be 10 mv. If you plan on doing any kind of work on it you should know how to work around potentially lethal voltages.