Help me care for of my 72 Fender Twin Reverb

[jlonigro]

I have a silver face Twin reverb that looks completely stock. What is the best way to keep this baby in nice shape? Any preventative maintenance should be performed? As far as the output tubes go three of them are Sylvania and one is RCA. I'm sure there is a matching issue. The power of the amp does seem a bit low. I've already replaced the pre amp tubes with Telefunken 12Ax7's because the 7025's were spent. I am a little confused about the different schematics I've seen of this amp. What is the difference between AB763, AA769, AA270, AA764 schematics? How do I know which I have?

[jlonigro]

Also when I look at the circuit board I see the following electrolytics.
(5) 25MFD 25V
(2) 50MFD 70V
(1) 5MFD 50V

On most schematics I've seen there is what appears to be a multi can cap (B, C D) with 20MFD 525V and (2) 70MFD 350V caps. I don't see these. Shouldn't they be very obvious?

[Twist]

There is no multisection cap on that amp. Under the amp chassis is a rectangular cover and under that are some electrolytics. Unplug the amp to give the caps time to discharge then look at those filter caps. If they look original I would recommend taking it to a tech and having them replaced. You'll be surprised at the results. Also have someone install a matched quartet of output tubes. An experienced tech will know other common problems to address like cold solder joints and dirty pots.