What?   Just what large cap were you expecting?  This is not a single rail amp like older Acoustics.   Look at your schematic.  RUns on plus 42 to minus 42 volts.  Not plus 90 and ground.  The output sets at zero.  No need for a fat cap.  The fact it is quasi doesn't matter.

Your schematic shows no output jacks.   But if I were to guess, I'd say the extension jack puts the extra speaker in series with the main, rather than parallel.  SO the sleeve can be grounded, and the tip cutout goes to the sleeve of the main jack.   Thus the main jack needs to be isolated.

Why would they do that?  If they made it parallel jacks, then any moron could plug a couple 4 ohm cabs in there and load the poor amp to 2 ohms and blow it up.  Now a couple 4 ohm cabs makes an 8 ohm load.

We do find schematic errors now and then, but I think it is wise to resist the urge to immediately label something we don't understand as a mistake.

I rebuilt many many many jukebox amps over the years.  Mostly Seeburg tube amp and Rockola solid state.  But Rowe or AMI or whatever, we did it all.   I don't recall ever seeing cap kits.  I don't doubt they exist, but I just maintained a stock of parts and had no need.  I did a ton of CRT monitor repairs for the arcade trade, and they did offer cap kits for those.

That said, I am not aware of any cap kits for amplifiers, and especially for a relatively unusual one like that.  But such parts are easily available.

I am not where I can post at the moment, but google "Peavey semiconductor cross reference"  or "peavey semiconductor guide".   Many places will have it for download.

Rail is just a informal term for power supply.  For example, your amp has a +27v and a -27v "rail", also has plus and minus 15v and also 13v rails.   There is no physical rail thing, it just means a point in the circuit that multiple things connect to.  SO in your schematic, every place you see a arrow pointing up with +27 next to it is connected to every other place with an up arrow and +27.   And that imaginary common point is the +27 rail.

SO as g1 suggested, check ALL of those supply voltages to see if any are missing.

And did we unplug the footswitch?

Is the FS the real Fender FS for this model?  Or is it some stomp switch you had from something else?

Is there ANY sound in the speaker?  BAckground hum maybe?

Turn up the reverb and bang on the amp to crash the springs.  Does that noise come out?

Oh, don't sweat any that are off a bit.  We are concerned they are shorted or not.   I'd wager your testing is not done at full current, but rather with a meter, and that is like tuning a race car engine at idle.   You are blowing fuses, and gain variation will not cause that.

If you are blowing fuses, suspects will be:  output transistors shorted.  Bias string open somewhere (perhaps at the sensing diode connector).  Shorted rectifier.

The Hot Rod series do have some things that happen to a lot of them, BUT, there is a difference between "When they fail, THis is what often happens" and "This usually fails in an amp."

WHEN an amp comes in with channel switching problems, I know to look at the two hot power resistors.  But that does NOT mean that all the aamps do that.  Most of them do not have a problem.

"Leaky" caps don't usually look different.  The leak refers to electrical operation, not some goo oozing out.  That can happen too, but it rare.

My point being I generally do not like pre-emptive wholesale parts replacement.  We would be more likely to cause problems than to prevent them.

Visit shops or repair techs in your area and ask what they use, and if they would buy another one when that one dies.  What do they like and dislike about it.

I have used Weller irons all my electronic life.  I like the WTCP series, but they make a variety.  I also use Pace equipment.  More costly but I like it, been using my Pace desolder station for decades now.

But there are other good brands like Hakko that I have never used, but many like them a lot.  So you can find good equipment that is not what is in my shop.

U3 and all those caps are the chorus clock circuit, they are not in the audio path.

U2, U7 Q6, Q7 are the chorus path.  MAybe Q5 too but I doubt it.  Turn chorus on, you get hiss.  Power off, remove U2, power on.  His still there?  You won't get a chorus signal with U2 gone but we are looking for the noise now.  Still noise?  Remove U7, same question?

Make SURE not to install ICs backwards.

Hamburger claw meat just isn't that good to start with...

It is fun to try to tweak an amp for tone, but remember, no matter what you do to a hamburger, you will never make it taste like a lobster.

The MJE150xx series are useful in a number of situations.  I use them

I suspect Traynor uses them in some other product, and has them on hand.  The MJE15032 is rated at 250v versus the 60v rating of the 2SC2233,  and 8A versus 4A, so it is overkill.  I am sure it works fine though.

In tube amps, a EL34 will sound different from a 6L6, but transistors don't work the same way, and especially in power amps, you can use pretty much anything that has the minimum specs covered.

A guy brings me a 1969 Corvette with a flat tire.  I put a brand new Goodyear (or Michelin or whatever) on it, balance up fine, car drives fine.  Now do I check to make sure the guy doesn't have his heart set on an actual 51 year old tire for it?

Quire often, it is just outputs.  I usually replace the drivers too, but if it is working, they may be fine.  And if the two 1/2 ohm resistors are OK, and the 150, 150, and 22 ohm resistors are OK, likely it is fine.

SOlid state amps like this and a million others are massively fed back and self-correcting, so pretty much any transistors that will safely work there will sound about the same.

There is no bias adjustment, so if it works, doesn't get real hot, and sounds OK, then I'd stop fixing it.

Those voltages look fine for idle DC levels, but they don't tell us if the parts can conduct current well.

You can probably find 2SC2233, or the common TIP41C would likely work fine too.