[ARC5] Tube Question

[Randy Randall]

 You did not mention the model and brand of the tube tester so I'm going with some generic suggestions. Since it is a simple tester you can calibrate using a resistor of a  value usually specified in the owners manual to set the calibration.  Do a search on the make and model on Google and I'm sure somewhere you'll find an owners manual with those instructions. The only tube testers instructions I've seen that was suspect was a Mercury Model 1100. Calibration instructions on that unit was to take 5 new 6ab6 tubes and test them all and take the average of all of them and set the meter to that point. Seems hokey but that was their calibration procedure.  Also back in the day some less than reputable TV and radio men would deliberately misadjust the tester to read low to sell more tubes.  Also if your tester has a line Adjust setting make sure that you set that with the tube in the tester in the filament lit with the correct settings. To be sure follow the directions in the manual.  One last thought if you own an Eico tester model 666 or 667 the tube charts were notoriously inaccurate. Do a search and you if you own this tester and you can find updated charts, but even the newer ones had errors.   Good luck Randy.

Sent from my iPhone using speech to text technology.

> On Sep 20, 2015, at 11:43 AM, Robert Eleazer <releazer at earthlink.net> wrote:
> 
> I finally got out the tube tester I bought a while back and stared learning how to use it.  It is simple emission tester. 
> 
> I found something puzzling.  I have two 6AW8A tubes that were sold to me as good and a 6AN8A tube still in its original military box; these are basically the same type tube.
> 
> In the tube tester all three test as bad, the meter needle in the high area of the "replace" range.  Also, the meter needle wavers.  However a slight upward adjustment to the Shunt control shows the tubes as good.  This is true for both sections of the tubes.
> 
> Anyone have any ideas on this?
> 
> Thanks,
> 
> Wayne 
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