Pro Reverb Vibrato Help

[lgehrig4]

I have a '68 Pro and I when I engaged the vibrato and instead of the effect all I heard was clicking in it's place. The clicking speed could be controlled by the speed knob. I went to check the tubes while this was happening and through the unused speaker jack I could see an orange/yellow light blinking with the clicks. I checked the tubes and they weren't doing this to the light was comingform the inside.

What component do you think it glowing like this?

[davemccarthy707]

Thats the opto isolator. Open it up and see if there is heat shrink around it. If there isnt it wont work.

[Billy Penn]

Thats the opto isolator. Open it up and see if there is heat shrink around it. If there isnt it wont work.

You have to open the chassis to check this out. Something is up with the optoisolator. Like davemccarthy said the heat shrink has probably somehow come apart. It may be as easy as unsoldering it and slipping some new heat shrink over it and re-install. But you have to remember which leads went where. That is important or it will not work at all.

[phsyconoodler]

Not true.I had a bandmaster with no heat shrink and the trem worked fine.
However it does work 'best' when covered.
You have another issue as well as the uncovered neon bulb.

[mark norwine]

ticking but no attenuation usually means the CdS cell could be shot.....

New cockroach time

[slider313]

One of the three ocillating caps; .02, .01 .01 may be shorted. I usually change all three. They are the three ceramic disc caps connected to pin one of V3.

[davemccarthy707]

I should have been clearer, what I meant was what he is seeing is the opto-isolator. If it is uncovered the trem "usually" will just tick, although sometimes it will work but be distant.

[lgehrig4]

Thanks for the replies! I'm going to bring it to a local tech

[JJman]

Mine can be seen flashing thru the end of the roach ( via the "ext" jack) when properly shrunk and functioning. If it's blinking, the tube and the caps are working.

If the wrap fell off that could be the problem. Or the other half of the roach, or it's circuit is bad.