Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by renfra, Aug 8, 2006.
In my '63 Super Reverb vibrato syddenly stop working.
Can anyone help me?
even if you can see the roach flashing, it might need to be replaced. The LDR usually wears out way before the neon bulb. I've replaced two of these in my amps. They seem to have a lifespan of about 40 years.
Thanks, but what kind of roach is suitable for my vintage
Try the tube before you open up the amp. It is the 5th tube from the right when viewing the amp from the back (12AX7).
check with the parts suppliers (hoffmanamps.com, mojomusicalsupply.com, etc) as they usually have these, or at least used to, if you determine that is the problem. Check the tube definitely first but I assumed you already did that.
I have replaced the tube and the roach (Optoisolator). Still no Vibrato.
Signal runs through the curcuit even when Vibrato is switched on.
Any other ideas?
Thanks so much.
There are three ceramic disc caps in the vibrato section; a .02 and two .01's.
I replaced both .01's and the .02 ceramic caps and still did not happen. But, Now I can hear the Vibrato want to kick in, but....no.
There is a slight volume change when I mess with the intensity knob.
Anthing else come to mind?
The Optoisolator is from Mojo (silver dot toward the tubes).
if the cathode cap on the oscillator tube is old, that could be the problem.
There are a lot of wires under the board in that section of the curcuit.Check them(blue,yellow, brown,white)for continutity one may not be making contact.
I finally hooked up a reverb/vibrato swicth to my '68 Super last night (I bought it w/o a pedal and the vibrato was off) and although the vibrato works, it's not very dramatic. The vibrato on my other SF amps is much more pronounced. Would a tube change help this, or what else could it be? (Sorry, don't mean to hijack the thread, but the topic is very similar).
After going down the same path as you with my 68 super (AB763), I replaced the roach with the Tonecraft Surf Bug http://www.tonecraftamprepair.com/html/surf_bug.html
It not only solved the problem, but gave me the thick lush tremolo I was after. Worth every penny...!
I may just have to try one of those Surfbugs out! How much was it?
As I recall, it was about 25 bucks