Did you measured them off board or in circuit?
In the seond case some other component may cause that reading.
If you had a bad cap you would have strong hum, or instabilities, but not just "low power".
Those were very well made amps, the ones I remember were hybrid: SS preamp plus a couple output tubes.
Post a couple pictures.

Don't worry, I am fed tube amps up my throat every day too ... that's why I visit this SS haven so often.

capacitors don't need to be replaced with the exact item.  just go to Mouser, Digikey or Newark electronics, Antique radio supply. ( or other) and use a capacitor with the same values. I assume from 2200 it's an electrolytic. I prefer Mouser. They have a search that let's you specify values and links to datasheets so you can check physical dimensions.

If one electrolytic in an amp is bad often it is a convenient time to change all electrolytics. The other types seldom go bad with age (except wax and paper covered ones and your amp is way too recent for them)

Gah, I've had transformers on the brain lately, I meant to say transistors. 
Also, I should probably have said DC power rail instead of HT rail.

Man, I've really got to take a break from reading about tube amps, I'm confusing more than just myself! 

I have a KMD GS130SD amp that has been stored in my garage for 18+ years. It powers up, but only the clean channel plays, but at no more than half the volume that it used to! There are two Phillips capacitors, 2200uf 100v 2222 050 59222, One runs out to infinity, but the other runs up to about 430 and stays there (When tested with a DMM). I can not find these capacitors online. Does anyone know where I can find these or can I cross reference with something else? Also I am not sure if this is the problem, but I figured it as a starting point!

Thanks a lot for the link for schematics DJPhil, this is a great find. I could not find these anywhere. On the K 200 I think I may have a bad transistor on the driver board. It looks hinky so I will try to find a replacement and change it out. The 150 I really dont have a clue so I may take some time on this one. I will get back with any progress.

Am I missing something here? 
Which HT rail?
Which output transformer?
And even if that Kustom did use one, it would be almost last in a looooooooong list of things to check.

I dug around to find some schematics, you can probably piece most of it together from here.
You can use the block diagrams to get specific board numbers, they're listed separately in the PC section below.

K200-1
No signal from the power amp. I'd check and see if you're getting any output from the preamp board. This might just be a loose connection or dirty switching jack.

K150-2
This sounds more serious. Which fuses? An AC line fuse could mean a dead transformer, where a dead HT rail DC power rail fuse probably means a short in the power amp, likely dead output transformers transistors. (brain fart)

Ungrounded plug
This is one for the pros. I'd strongly advise converting these amps to grounded plugs, but I'm not 100% certain about how to do that with the way the power is set up so I'm giving no advice. It'd be much, much safer to use (for the guitarist and the tech) if converted.

I'm just the new guy, but the pros will want to know more, so I figured I'd help get you started.

 Hello, I have 2 Kustom heads that need a bit of work done. They are a K 200-1 and a metal slant face K 150-2. The K 200-1 when turned on does do the soft pop to the speakers that my working Kustoms do but no sound other than a slight hiss.      The K 150-2 blows fuses when turned on. Both of these amps have the original cords without ground pins. I have never really worked on large amps such as these but I build pedals regularly and I know how to use a multimeter. Any help I could get would be appreciated.  Thanks, Will

Well I decided yesterday to really dig into this amp and see what I could do, first off the normal channel never has worked right and there was always a loud squeal when plugged into it. Had a tech tell me the norm jack was bad and went ahead and replaced it, squeal gone but the norm channel stayed on all the time. I could toggle the effects channel on and off but the norm stayed on so always figured there was a messed up switching chip in it or something. So I switched out R50 from a 33k to a 22K in reference to another forum member and put 2 LED`s in series on R11 per the same forum member and plugged her in and tried her, did not like the grungy sound the LED gave so pulled them and went back to norm. The 2 resistors I changed added a little more distortion but with the effects channel pre gain on 10 it was super bassy and compressed, on 9 it had a decent rhythm tone but the lead tone was still not edgy enough. The 2 channels on the amp are suppossed to run paralell to each other and you should be able to boost 1 channel over the other, not in this case. I don`t know why but I decided to put both channels pre gain on 10 and set the effects channel on 1 and started turning the normal channel up to see what happens, the more I turned it up the more the bassyness and compression went away. Then this sweet little crunch came out and a cool growl and tone the amp never had before emerged. So I played with the eq`s on each channeland kept raising the norm chan volume and it got better and better. So it appears the amp has been rewired with the channels in series like i wanted to do. It would have been nice if the previous owner had told me this and saved me and everyone else alot of headaches..lol.