No Tremolo ?

[Alex R]

well if it works it works I guess, but as the OP mentioned having converted the bias pot from bias balance to bias adjust I would have wondered whether this (in my view negative in effect but often recommended) mod also involved removing the pot's connection to the trem circuit, which on this amp works directly through the bias pot by varying the bias.

[52 Bill]

...mod also involved removing the pot's connection to the trem circuit, which on this amp works directly through the bias pot by varying the bias.

Alex, we are talking about a Vibrolux Reverb with a photo cell tremolo here. While the bias voltage is used to kill the trem LFO it is not being used to modulate the output tubes.

[g1]

I don't think it can flash if installed wrong .

Maybe it's the high voltage arcing across the Cds cell.

Well so much for that theory , like they say, never assume!
Thanks 52Bill for the explanation.

I was joking, I assume that it was flashing when the original one was installed.

Now I'm lost Bill, how was the thing flashing when installed backwards?

[52 Bill]

Now I'm lost Bill, how was the thing flashing when installed backwards?

My assumption was that the original one was installed correctly but had a bad photocell so flash but no effect.

New one was installed wrong, so still no effect. I also assume that the new one is the type that is better sealed so that in any case you can't see the flash.

New one installed correctly, trem works.

Only gp76 can fully explain the sequence of events.

[g1]

Ok, I had missed the part of the roach being replaced. So the question is whether in post #1, when he said the roach was flashing, was that the original or the replacement?

[Tom Phillips]

Wow. The reported observations and the actual sequence of events are sure difficult to figure out. 52 Bill seems to have the only plausible explanation. (In post #19 that is. Not post #11)

It's often difficult to keep the sequence of events straight during trouble shooting. I know that if I don't keep good notes during certain troubleshooting investigations I will miss important clues or circle around and end up trying the same things over again. When you are describing the situation to others then it can be even harder to get the facts exactly correct and in the precise order.

Anyway...I'm reminded of a story that illustrates how important it is to say exactly what you mean...
There were two guys told to install steel fence posts in the ground. One guy fancied himself the leader. He grabbed a post and handed the other guy a 10 pound sledge hammer. The guy with the post kneeled down and said "I'll hold the post where I want it and when I nod my head you hit it with the sledge hammer." The result was not good.

[Randall]

^^^ took me a second, but funny.