If you have cleaned the volume pot and it still crackles or you have channel drop out you probably need to clean the balance pot. I am no expert, but I use fader lube on pots and contact cleaner on switches. Both caig deoxit.
I wonder if the C-1000 is really a true Carver product or if it was a modified unit based on an existing or partnered design. The reason I say this is because the front and back panel layout of the C-1000 are very similar to the Rotel RSX - 965 DD/DTS receiver (75 watts/channel) that came out around the same time. Google some pictures of that Rotel receiver and you will see what i mean.
The C-1000 has only composite and S-video so it is useless for video switching. (not all that important to me or many others). I owned a used C-1000 in 2004 and it spent 6 months in the repair shop. It was horribly problematic. The sound was nothing special. Granted it could have been a bad unit all around. It has pre-outs for all channels but you can't use it as a 5 channel amp on its own. They look great but frankly if something goes wrong with it I think it will be very difficult to get it repaired. There are simpler and better options. My 5 cents. (we don't have pennies anymore in this country so minimum is a nickel)
It's pretty difficult to repair an amplifier without any electronics knowledge. If it's blowing fuses there could be some major faults that you can't find just by looking at it. I'd say take it to a repair shop if you want it working.
My Sunfire Ultimate Receiver is quite sensitive to any DC on the main line. DC from appliances such as my humidifier. Even a few millivolts causes the Sunfire transformer to buzz.