Hi guys I'm going through my newly purchased TV-2/U tube tester and have been experiencing problems with the Bias adjusting pot . was wondering if anyone has tried to replace this pot with another 10K , unlike the English wheel type pots on the Hickok 800 this pot does not have to be in sync with a graduated scale , I don't myself see any reason why any 10K pot that is precision enough and has correct wattage would not work . Brings me to my next question what do you believe would be the correct wattage for the 10K pot in this unit . was thinking of using a precision wire wound 10 turn 2 watt but not sure the wattage would be enough.. thanks for any help
Just a update for anyone having this problem , I was told on another site that a 2watt pot is well over what is required and any 10K pot should work as long as it finely enough wound.. Have ordered the part and will update with the results .. cheers
Received the replacement 10 turn bias pot today and installed it , wow what a difference , so easy to adjust now and it seems to have stabilized the whole machine because everything is working better . Must be that the short in the windings was causing problems in the TV-2 in other areas . Anyway it's done and that area is working perfectly . I do have a question for anyone using a TV-2 ,it's about zeroing the quality meter , I followed the updated instructions and zero in F range but find the the zeroing pot so sensitive that even the smallest adjustment of the pot even if it makes very little if any difference in zeroing can make a huge difference in the measured quality reading . What I am saying is you can change the pot adjustment quite a bit at zero adjustment without moving the zeroed meter but that same amount of movement can change the test result 25% . I'm thinking the lower end of the quality meter pot may not be reading correctly but the top end is making it impossible to zero without a calibrated to set it up with . Maybe time for another 10 turn pot . what do you think guys .. I also machined up some new lenses for the short and pilot lights as they were missing
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Ok so I dug into the quality zeroing pot and found the problem , this time it's a manufacturing problem that may affect many TV-2 units .. What I found was the pot wiper was hitting the winding rivet long before the pot hit it's end point of it's travel , this was causing the pot to have no control in the lower end of it travel . effectively making the lower end of the pot dead . it's a easy fix you just need to carefully tweak the wiper arms up to clear the rivet and you now have a pot with smooth predictable response in the lower part of the scale where you need it to set up the quality scale . Now setup is a breeze