Center channel dosen't work on 10 yr old marantz 500$ receiver. Should I just buy a new one?

Check the speaker output settings on the receiver. The receiver may be in a 'stereo' or 'two-channel' mode only.

if it's a blown amp channel, might cost around $150 to repair

http://www.buy-remote-control.com/

Changing the type of fuses in your receiver will not change your sound quality at all.

Get the manual and open it up to the part where speakers are defined, then test it/them with tones. Try swapping a different speaker into the center if the current center channel speaker still doesn't work.

Web search "Marantz SR-5005 manual" (note the spelling)

It sounds like you've read one of my many posts on 901 deployment in the AV world.

Functionally, what is the difference between one amp with 'x' channels or 'x' mono amps? Nothing. Pre-outs don't know or care what else an external amp does.

According to this link http://www.ecoustics.com/electronics/products/new/642968.html those amps are 2- and 5-channel, respectively.

There was a time when I had two bridged-mono Carver Cube atmps (at a real 400 watts) pushing one 901 each but that was big time overkill.

I now use a Carver AV-406 (functionally the same as your MM7055) with the 901 EQ in between the AV Receiver's front pre-outs and two 110-watt channels. Other channels on the AV-406 pull subwoofer and surround back duties. My AVR directly powers only the center and surround speakers.

The MM7025 would work for you.

There is a 1 Farad "super capacitor" that needs to be replaced. You need soldering skills to do it. The board is accessible if you remove the front panel of the receiver. The part # is DB-5R5D105; you can get them on eBay for about $2.00 each. Regarding the center channel issue, you may have a bad solder joint on the P781 connector on the P774 board. This is the board that houses the output transistors for the 3-channel main amp board (P704). If not these solder joints, you have a weak driver transistor on P704, and troubleshooting would probably be best left to a pro. Good luck!

I had a similar problem with a jvc 8040. when I replaced the fuse it became very obvious that the b1560 output on the center channel was blown (smoke and sparks, always a dead giveaway). I haven't fixed the center channel yet but simply unplugged the center channel board and removed it from the unit. Now everything works fine except of course the center channel. Pre outs still operate just fine so a slave amp could be used for center channel power, or you could just go and buy a marantz amp; I did and then I realized that I was lucky that the old jvc quit.