Fender Blues Deluxe reverb problem

[Tom Sawyer]

I'm new to this forum and I'm a guitar repair tech who rarely works on amplifiers or sound systems. I own a Fender Blues Deluxe (1996 American made) and the reverb pops in and out randomly. I've De-oxed the microswitches that change the channels and all of the inputs as well as the connectors at the reverb tank with no success. I can make the reverb pop back in by thumping the top control plate.
Has anyone out there had this problem?

I'm out of my league with amp problems!

Thanks,
Tom Sawyer (really!)

[Jazz P Bass]

What is the 'Top Control Plate'?

[Tom Sawyer]

What is the 'Top Control Plate'?

By top control plate I mean the actual control section of the amp (volume, tone, reverb etc...). Instead of a front loaded control panel, the controls are on top of the amp. When I tap the chrome plate, the reverb kicks back in. Tried it again last evening and I noticed that the led for the channel switch pops on when the reverb cuts out which confounds me even further! The reverb is not footswitch controlled.

The humidity level in my teaching studio and guitar repair shop is at approximately 40 to 45% almost all of the time because of all the instruments in storage or on the bench, so that really shouldn't be a factor. The amp is on an elevated amp stand which tilts it back so heat build up could have been a contributing factor, I suppose (this particular model, although an open back, has a rather elaborate back protection panel that could really be restricting the ventilation).

Thanks for your interest and reply

T.S.

[Jazz P Bass]

If tapping the amp makes it work, then something is loose.
You can tap (with a wooden dowel) the circuit board & try to narrow down where the loose component is located & resolder that area.

[52 Bill]

By top control plate I mean the actual control section of the amp (volume, tone, reverb etc...). Instead of a front loaded control panel, the controls are on top of the amp. When I tap the chrome plate, the reverb kicks back in. Tried it again last evening and I noticed that the led for the channel switch pops on when the reverb cuts out which confounds me even further! The reverb is not footswitch controlled.

If the problem comes and goes with a mechanical stimulation, then there is probably something loose on the board. If fact your amp is old enough that it could be the typical low voltage power supply problem related to the large dropping resistors and Zener diodes coming unsoldered due to overheating.

If you have the skill set to safely remove the pc board and resolder the loose parts, then that would be the next step. If you don't have the ability to do this safely, then it needs to go to a qualified tech.