[Solved] Carvin XV-212S reverb stuck on [footswitch issue]

I have a Carvin XV-212S (British Speakers) from 1989 that suddenly has a weird issue. The footswitch operates (toggles the light), but the reverb in the unit is always on. The reverb knob still affects it (so can dial it to zero), but I am not sure if this is an issue internal to the amp or whether that implies the pedal is faulty. I am leaning toward the footswitch being bad, since if it is truly toggling the guts, I would "expect" the knob not to function.
 
This amp is a bit complex on the guts side, so any advice would be appreciated. Here is the best current link to the schematic. The reverb path is in the upper left, and I do not see how the control would still operate if the switch is actually toggling. I am going to need to clean the pots on this again soon anyway, and wanted to get some insight before I do that.
 
It seems Carvin is doing less and less over the years, so not sure where I could even get this thing serviced. It still has the original tubes in it, so at some point this will need real TLC. Most folks I found anywhere near me only service vintage amps and some specifically say they won't touch a Carvin (ouch).

Well without seeing the schematic for the footswitch, it is really hard to nail it down. If it is some sort of DPDT switch on the reverb and one pole controls the LED, then the LED could light if the switch's actual reverb-switching path shorted closed, but a switch will usually short open if it goes bad.
 
If the footswitch is OK, I would first suspect Q6 went bad, always being "open" so the reverb signal never shunts to ground. After that, I would suspect Q7 is bad or A6 is bad, in that order of likelihood.
 
Anything that has solid-state switching schemes more complicated than simple relays will scare a lot of amp techs away. Carvin is harder to service for that reason and the fact that unless you are an "authorized" Carvin service rep they only have access to schematics have areas in them that are obscured to protect their "trade secrets." Also Carvin uses a lot of tube/solid-state "hybrid" schemes in their preamps... another thing that will scare your typical tube-amp tech away.

do you have the model number of the footswitch? there are some footswitch schemaitcs online at the Carvin Museum website.

OK looking at that schematic and pictures of the FS36, it would pretty simple to wire in a new switch if you have even a tiny bit of soldering skills or know a buddy who does.
 
You would just need one of these...
https://www.tubesandmore.com/products/switch-carling-footswitch-spdt
 
While you are there, you can get this to tune-up your amp...
https://www.tubesandmore.com/products/tube-set-carvin-x-vi12-later
 
Buying the two together from them will get you free shipping.
 
If that doesn't fix it up then you would have to dig into the amp itself, checking those transistors and logic chip. For that you would either need to have a bit of experience trouble-shooting amps (not recommended if you don't know what you are doing --- there are LETHAL voltages inside tube amps -- even if it's off and has been for a while!!!) or it needs to go to someone who does know their way safely around the inside of an amp.
 
Footswitch schematic is here...
http://www.carvinmuseum.com/pdf/misc/fs36.pdf
 

Thanks everyone for the feedback. I just got a chance to delve into this further and the foot switch was the issue.

Yes, thank you. Turns out the switch cable was chewed into 2' sections by a puppy in 1992, so I had salvaged both ends and have had a 6' cable since. That splice got stepped on so was a simple find, but I do need to replace that still. I got caught up with things this weekend and was just happy as a clam that I didn't need to troubleshoot the amp itself.

Thanks again for the help.