IF transformer ATE-068
- Thread starter Jauk
- Start date
Hi. Current situation is when I turn it on the values for the three adjustments of "Detector VT adjustment" as described on the SM, measured on the proper test points, are about 90mV for T201B, 180mV for T202B and 70mV for T203. After warming up (20 to 30 minutes, haven't tested less time) without the top cover they change to about 19, 15 and 8. If I leave the top cover on for 30 minutes or put some clothes on top of it, it changes to around -60, -50, -40.
BTW service manual says to adjust between +/-100mV. Ambient temperature of the room is about 21°C (68,5°F).
It always tunes automatically even with values out of +- 100V but when I first adjusted it (when I first found out the DMM was out of scale) T201B was above 1V! I suspect if I change it to 300mv or more it will stop working at some point.
BTW service manual says to adjust between +/-100mV. Ambient temperature of the room is about 21°C (68,5°F).
It always tunes automatically even with values out of +- 100V but when I first adjusted it (when I first found out the DMM was out of scale) T201B was above 1V! I suspect if I change it to 300mv or more it will stop working at some point.
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Congratulations on your repair!
Good for you sticking with the repair.
Good for you sticking with the repair.
Somethings not right, I tested the donor unit (an F701) and it's rock stable, varying only a little more than 10mV! Do you think it's more likely the IF transformer (maybe it's capacitor..) or the circuit ? The funny thing is that all 3 test points relating to this adjustment on the F93 jump a lot with temperature, not just one, and they don't seem to be dependent on each other (i.e. if I change T201B others will more or less keep their values). Would be too much of a coincidence if all transformers were screwed up, so maybe it's the circuit. I can transplant the transformers from the F701 and a third doner unit (F701 has only one ATE-68, this is getting expensive!) to the F93 and see the results but man, it's getting boring 
But I think I'll do it. Or maybe it's some other adjustments elsewhere that were messed up with, I honestly have no idea ...
But I think I'll do it. Or maybe it's some other adjustments elsewhere that were messed up with, I honestly have no idea ...
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