Bulb should not be lit. Light from the neon decreases resistance on LDR which is the "R2" of an R1-R2 network.Sounds like DC is getting to the bulb. Check the neon drive side with scope for waveform or DC. If DC, leaky cap is to blame.
***there is a DC bias on the bulb, but it is the AC waveform riding on the DC bias that flashes the bulb.***
So the 220k V5A plate load resistor had blown. It was hard to see. I replaced it, but now the trem works fine, but the pots (intensity and speed) are noisy/scratchy. And playing guitar through the amp while trem is on... every other strum/note sounds scratchy/distorted. When the trem is off, amp sounds fine. The amp wasnt like this before that resistor blew.
You should not hear noise on the speed pot. It is not in the audio path.
Its a twin reverb reissue chassis that I converted to a hand-wired AB763.
Yeah, exactly. The only other thing I changed before it blew... the intensity pot lug 1 was grounded to the pot itself... but I connected it to to the preamp ground line.
No signs of Stress. And looking at the busted resistor, it doesnt even look burnt. It just looks... broke. The new one isn't getting hot (granted, its a 1 watt).
Yeah, thats what I mean. Looks like it just broke, like it got smashed or cracked physically... I dont know how... but...
