Crate GX-20M burned resistor + popped cap values?

1. Sounds like it's the input jack., but it could be the volume knob. Have you tried turning Gain1 and Gain 2 or the Clean Channel volume? Try them first when you're plugged in to the jack on the left , then when you're plugged in the back. If none of these work, it's most likely the preamp. 2. Even if the preamp is shot, there's a quick fix - get a guitar preamp or an effects pedal - they have volume and tone controls. 3. Finally - many pros just plug into the aux jack(on the rear panel) and control the volume and tone through their instruments. Hope one of these works. Good Luck.

The fuse rating should be printed on the panet right by the fuse holder. If there's still a question about values, you're best bet is to contact Crate customer service.
Here's the link-
http://www.crateamps.com/support
However, if you're meaning that you keep blowing fuses and therefor think you're instaslling the wrong value, you may have a short in the amp that's casuseing the fuses to blow. In that case, it needs to go to the shop. If you're not a tech, don't poke around inside it. You can make the problem worse, or even get a nasty shock.

Clean the volume and tone pots with de-oxit cleaner

Power supply capacitors failed. This is a common problem with 1990's crates, also the power on "POP".

I also have this issue. Same crate combo amp. There is a loud buzz emitted only when there is a cable plugged in. Cables and instruments checked good, only possible issue is inside the input of the amp. Popped it open, solders and connections were intact and appeared solid. Anyone have a guess as to why this is happening?

Witth an oscilloscope analyze the ripple voltage across C67, C70, C14, and C12. Pay close attention to the last two of these which are on +/- 15 volt lines.

The "chirp" when shutting down is LIKELY normal and would probably be from teh DSP effects unit as it goes down. The voltages go out of the operating range and the device essentially goes nuts for a second or so.

When you are changing the DSP effect on the fly, static or noise is NORMAL !!! The DSP is changing the data and having to recalculate on the fly and doesn't mute itself while doing so which results in "garbage sounds out".

The bypass setting should NOT get any tone UNLESS you have feedback going on. If your guitar can "hear" the speakers in the amp, the strings can vibrate and get feedback going.

Unplug the guitar and see if high freq tone is still there on bypass. If the tone is in the musical range, then there is a problem if nothing is plugged in. If it is a VERY weak, very high frequency tone, this may be the digitizing noise from the DSP. On bypass, the audio is likely to still go through the DSP, just not be modified by it.

NEVER use switch cleaner such as DeOxit on pots !!!!!

I have used CRC226 available at Home Depot electrical dept.

I SUSPECT that the resistance element in that pot is cracked. This is common if the knob sustained a hit. Replacing the pot is the only cure if the element is cracked.

Reviewing the schematic, ALL audio passes through the wiper on the HIGH tone pots. If the wiper is intermittent, so will be the sound.

If your unit is solid state amp, the pot looks like a 10K ohm LINEAR taper.
If you have a tube type, then the pot is a 250K ohm LINEAR.

Note that the other tone pots in the units are AUDIO tapers, but the high is a linear taper.

Get repair parts from either DigiKey.com or Mouser.com

Not a fuse. First thing, to check your speaker (amp unplugged, of course), touch the + and - speaker connections to a 9V battery. If you don't hear a pop sound then your speaker is blown. Thus, no output sound. If speaker is OK, then the output IC is your problem.

if they are square cement power resistors they are probably 3-5 watt 300-500 ohm .... are there colored stripes on the resistors? those are probably grounding resistors, they usually are installed too close to the board, get real hot a bunch of times and then crack the solder welds. when you replace them bring up the height and make space under the resistor to keep it off of the board and put a little drop of silcone underneath to hold them in place.