Got to do the alignment real fast otherwise you might trash the mod transformer. Mine started smoking but seems OK after it cooled off.
I run my Retro off a 1 amp current limited supply. For those that hook theirs to a bigger supply, or a big battery, I suggest a 1 amp inline fuse. I'd rather pop a fuse instead of burning up the rig in case of a high current internal fault.
The issue here is that while tuning the VFO up, there may be moments with no drive, and the RF power fet driver may turn on. Here we have 12v feeding a saturated fet and the only real impedance in between is the ~ 0.3 ohm winding of the modulation transformer.
This reminds me of keying a tube final with no excitation, and no protective bias.. i.e. the plate meter hits the peg. Once the VFO board is tuned up (two RF transformers to peak), there are no more lack of RF drive concerns.
I understand that the VFO kit instructions have already been edited to tune the VFO board before connecting it to Rf chain.
Jim
WD5JKO
