Mi fender rot rod deluxe has almost no power, the volume its very very low, clean sounds distorted. Before lose the power, the clean already sound distorted at low volume, like at 4, its starts to sound over drive. like i said the amp lose almost all the power. The tubes are new and biased, the speaker its good, what could it be?

Check your tubes. They may be broken and have to be replaced.

leak capacitor must replace or ics

try a differrent speaker of suitable wattage and ohmage (displayed with a number next to a ? symbol on the back of the speaker),

or

remove the original amp speaker and gently push in and out on it, checking for uneven resistance or scratching. the speaker should retract and return smoothly, without any scratchiness or uneven resistance from within, and if there is any of this scratchiness or uneven resistance from within, the speaker is likely damaged from too much wattage or distortion.

First thing would be try another guitar with the amp. This will eliminate if it's a problem with the guitar or the amp itself. If the guitar is working properly then check all the tubes to be sure they are all seated into there slots completely. Depending on how much use they have been played it may be a good suggestion to then replace your tube's. Occationally the tubes will start loosing power, making sound fluctuate up and down or distortion sounding static in background noise. You will notice a big difference with newer tube. But remember the bias must be set correctly to match the new tubes so they won't over heat. You can check out youtube for setting the bias. Anyway this is my suggestion and I wish you good luck.

Realize that the number on the volume control is only relative... it means nothing regarding what the amp can produce. With a high level output guitar you can easily drive the amp into distortion at very low volume control level settings... what counts is the actual output sound volume and specifically the voltage output going to the speaker. Once the amp reaches saturation, any further input just pushes it into distortion or "flat topping".
An oscilloscope on the output will quickly show when amp starts to flat top.

Just because tubes light up does NOT mean they are good or working... While heaters not lit are an indication of failure, teh reverse is not necessarily true.
Time to troubleshoot this... Plug a set of headphones into teh preamp out. See if audio there is clean... it will be low level using headphones and ONLY from one side as the output is mono and your headphones are stereo usually... If audio is clean here and not muffled, then problem is in power amp section else in the early stages of the unit.
Report back the results of this test...

Wayne, There's a time to take the amp to a pro shop andf get it done right. It' saves time and headaches, and also keeps you from inadvertantly smoking other parts or yourself. Now is that time.

There are many components in the system. Electrolytic capacitors are most suspect. C49, C50, C45, C51

There are many others but these are top suspects. You MAY be able to detect a change by cooling these components with circuit cooler spray.

ALSO check the +/- 16 volt power sources in the unit.

It sounds like a filter capacitor(s) has failed. The electrolytic caps dry out and cease to perform allowing unfiltered power to reach the preamp sections and get amplified.

Being this is tube with high voltages, an experienced person should work on it due to shock danger.

I assume you checked the tubes for shorts as well as emission since a heater to cathode short could cause this as well.

First try turning the volume control down before turning switch to operate.

IF this seems to fix it, IF the unit has a tank reverb, the vibration of the reverb springs MAY be causing the problem. The solution then is to reduce the volume before applying power WHICH is a good idea anyway... from an electrical engineer.