[morzh]

OK. You did not do what I suggested? Measure the V-avc on at the cap of the 6A8?
That could tell you right away if you have a defective coil's secondary.


So, a suggestion. Before you buy anything, when the radio craps out, measure the AVC voltage both at C12 and at the Grid Cap of 6A8. If they are exactly the same, as a minimum, your secondary (and most important) coil is good.

And the primary is easily checked with ohmmeter (in fact the secondary is also, but the way I suggested it will check it right when it goes bad). Better yet, checking the primary with ohmmeter ca be done while the radio is on and crapped out, by testing Ohms between the chassis (or the "G" screw contact at the rear antenna connection strip) and "A" screw contact.