At least the B/W version is based on the Vermona Regent 100-G1.  That is the only one I found info for (from other threads on this forum).
Owners manual and schematic attached, you will have to check and see how far the schematic differs from the blue-silver version.

All your faults are typical pot/jack cleaning and re-soldering issues.  None of them indicate any faulty caps.
I doubt doing a re-cap will increase the value of the amp, meaning I expect you will get the same money for it either way.  For an amp you are not going to keep, it is a fair bit of extra work, with potential for creating issues, but that's just my opinion and I don't mean to discourage you.

Here is the schematic for the Deluxe 90 (non DSP).

I have recently acquired a Londoner L100A guitar amp which I am trying to find full details of online but I cant seem to find any official specs or manual for this amp and was hoping that someone here could possibly point me in the right direction or shed some light on these amps for me.

There also seems to be 2 versions that were produced that both share the L100a model number - the version with a black and white control panel and a version that has the silver and blue panel (which is the version that I have) and the differences seem to be more than just cosmetic.

The black and white panel amps have a semi parametric EQ on their Lead/Rhythm channel in the form of a 'Frequency' control and a 'Depth' control (along with the 'Bass, 'Treble' and 'Contour' controls for this channel. The silver and blue panel version however doesn't feature the 'Frequency' and 'Depth' controls and instead has a 4-way 'Tone Select' switch which is kind of unique and I would be most keen to know exactly what these 4 settings are adjusting in terms of frequency, gain, and bandwidth but I can't find any online manual or specs etc. Can anyone help me out here?

Other differences that I have noticed in photos of the 2 versions of the L100A amp is that whereas the Silver and Blue panel version provides a 'Bright' and 'Normal' input on its Bass/Organ channel (the same as its Lead/Rhythm channel), the black and white panel version offers a 'High' and "Low' input instead. The Black and white version also clearly states next to the volume control on the Lead/Rhythm channel that overdrive is achievable on settings of 4-5 but this isn't stated on the silver and blue panel version so I'm not sure if less gain is available on if this version has a different circuit board altogether?

If anyone is able to provide any info or history to these amps or point me in the direction of their specs, user manual or schematics, I would be most grateful.

I probably should've been a little more clear on the amp, yes it powers up and produces sound. Input 1 doesn't work at all and is actually loose on the board, hoping it's just broken solder joints. I put 2 barely works, but is scratchy, hisses and pops, looses contact pretty easy. Every pots dial was horrible and did the same thing, and the overdrive button was the same. Honestly it's impossible to tell what the amp really sounds like until those issues are addressed. The caps are actually look fine with no physical evidence of swelling, leaking, or bulging, so I did wonder if maybe at first I just replace the filter caps. As they are 26 years old. I really didn't want to have to pull the board multiple times I guess is the main reason I had for going ahead and replacing all the caps. When I'm finished I'll be selling the amp. Just wanted to send it on its way knowing it was good. I only have the layout of the board, nothing on actual signal path.

I actually had question to myself replacing all of them.....

Why do you want to replace all those caps?
Internet commandments about shotgunning electrolytics 'while you're in there' is most often just bad advice.  It sounds like the amp is generally working ok with no major hum issues.  Unnecessary repairs/parts replacement quite often creates new problems, especially for beginners.  Traces are delicate and can be broken, wires and cables can be damaged from just flipping the board over.  Solder bridges or poor solder joints, etc.
 
If this is not 'replace all electrolytics' but rather a targeted selection of caps, can you post the schematic and list the schematic designations for the caps to be replaced?

As far as other things to look at, I would be more concerned about bad solder connections.  Vibration and heat cycling can loosen up solder joints, especially around heavier components, or things doing physical work, like pots and jacks.
When these amps were current, and we worked on many of them, you would get to know which joints would commonly go bad, and just re-solder them as routine maintenance.

Since it was not blowing fuses, you can put the output transistors back in.
Like DrGonz said, voltage checks are the best way to proceed.

Since it has an output cap, it will be AC causing the hum, not DC on output.
You can disconnect the speaker if the hum is too annoying, and measure the AC volts at the output.

Schematic available here:  https://www.ssguitar.com/index.php?msg=16694

Hey all, I appreciate the add to the forum. I debated where to post this, but I am new to the board and just starting out with this repairing and rebuilding older amp thing so here won out. I picked up this 1999 model fender deluxe 90 for $50. Missing all the knobs, every pots is noisy, mismatched speaker, and some of the 1/4" jacks are not working. I thought the reverb tank was bad but it's testing good but the rca cable was not, so that's a plus. I'm cleaning all the pots multiple times, currently on the lookout for a 12" 4 ohm replacement speaker that's affordable(best deal new that I've found so far is a Celestion hot 100 for $80 plus tax shipped. If I can't find used I'll go that route. I've found replacements for the jacks if reflowing them doesn't work. Knobs were discontinued a long time ago but the knurled style are the exact same size, just don't fit the d style pots, but I still think I can make them work. Which brings me to the next biggest issue, cap replacement.

I'm leaning towards an order from mouser or possibly Newark , but I just want to make sure I have everything right. Here's a list of everything I need
QTY
DESCRIPTION
REFERENCE DESIGNATION
2
CAP AE AX .47uF 100V 20%
C17, C40
1
CAP AE AX 1uF 100V 20%
C15
4
CAP AE AX 2.2uF 50V 20%
C18, C34, C44, C47
2
CAP AE AX 10uF 35V 20%
C45, C59
6
CAP AE AX 22uF 25V 20%
C10-11, C32, C39, C61-62
2
CAP AE RDL 10uF 50V 20%
C57, C60
2
CAP AE RDL 47uF 50V 20%
C55-56
2
CAP AE RDL 100uF 50V 20%
C75-76
2
CAP AE RDL 4700uF 50V
C71-72

Mouser has everything matching the values I need in Rubycon and Cornell Dublier.
As long as I'm matching my cap values, should I have any issues replacing them? Should I be looking at any other brands. Mouser is about $34 shipped for everything. Newark is working on a price for me. Any other suggestions? Any else I should be looking at on this board while I have it out? Thanks for any input.

Well how about some voltage checks on the transistor legs? Personally I never pull a transistor unless it's dead or very questionable. I do chuck old dried up electrolytics in the garbage. Voltage checks and tracing signals are your best bet. A good transistor may never work if you have a cracked trace in the circuit board. What part of AZ are you? I'm in Scottsdale 👍

Hello all. I'm new to the forum and SS guitar amp work in general, but I built my first tube amp in the 90s as a teen, cut my teeth working at Rockford Fosgate/Hafler around the turn of the century, and have been doing tube amp and guitar effects repair on the side off and on for a while.

I'm looking for some sort of primer for how to diagnose a vintage SS Sunn Studio Lead amp so I don't have to pull ALL the transistors to test them.
 
The amp came to me with the complaint of "it only hums." I found that the caps were all original and the output cap had puked it's guts out. Against my own better judgement, I shotgunned all the electrolytics as the originals are all older than I am, and as one might expect, it did NOT fix the issue. The output transistors test good on my Peak DCA55. Voltages in the power supply seem to be more or less in the ballpark with the power transistors removed. I have a crappy USB Hantek O-scope, but it's been uncooperative since I moved recently.

If anyone could point me in the direction of some sort of primer on how to proceed without simply pulling all the transistors to test OOC, I'd greatly appreciate it.

T.I.A.,
Tim C in AZ