Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on January 05, 2019, 06:38:19 pm

Title: Super Reverb pedal issue
Post by: dude on January 05, 2019, 06:38:19 pm

71 Super Reverb 763, don't know if it's AA or AB, reverb works without pedal, normal. When I put pedal's RCA jack in, reverb doesn't work with the footswitch, simple enough, the switch is bad (grounding out the reverb)..? But the switch tests fine with no wires attached as soon as I attach the ground side to the switch the switch stops working (continuous continuity both on or off), grounding out the reverb.  Replaced the RCA male jack, still a problem, cable tests fine. All I can think of is for some reason when plugged in it's grounding out the reverb and makes no difference with the footswitch, on or off...? Pull the reverb footswitch cable, the reverb works.
Could it be a problem be with the female RCA jack in the chassis?  With cable out and reverb playing I short out the tip with a screwdriver, reverb off and on as I short the tip, but not with the pedal...?


Something not related to the pedal, cable or jacks...? Tried replacing tube, just make the reverb sound better, still the problem.


   

Title: Re: Super Reverb pedal issue
Post by: sluckey on January 05, 2019, 07:43:12 pm

Nothing wrong with the amp chassis. Problem is the footswitch assembly. Shorted plug, shorted cable, shorted switch. Keep looking.

Title: Re: Super Reverb pedal issue
Post by: dude on January 06, 2019, 11:33:25 am

OK, found the problem, short in the cable. One minute cable checked ok, bending it a certain way the short shows up  :sad: . Problem is finding the cable, Doug has stop supplying this two conductor shielded cable, Mojo has it but almost $30 shipped for a 12' length. Anyone know where I can get the Vintage Fender trem/rev cable?


One other question, the reverb sounds nice and deep, there was a .002 ceramic cap off input tank to ground that's not on the schematic but looks vintage. What does this do? Remove it?
The tremolo is weak, intensity has to be on 9 or 10 to hear it, where should I look? Also, the speed only starts at 7 up (plan on replacing the three ceramic caps in the circuit, anything else? Pop in the trem switch turning on, related to the short in the cable?


thanks,
al     

Title: Re: Super Reverb pedal issue
Post by: galaxiex on January 06, 2019, 12:10:39 pm

This guy has the F/S cable.

Scroll to bottom...

https://www.amprepairparts.com/footswitch.htm (https://www.amprepairparts.com/footswitch.htm)

Title: Re: Super Reverb pedal issue
Post by: dude on January 07, 2019, 01:16:14 pm

Thanks, galax


I searched trem fixes here found a lot on the subject if I can't get it working properly will post again. Learning to fish first, ha.