Carver P4 1999 Symphony

When I bought my Symphony the P4 would fire up, apparently normally, but after about 5 minutes would stop with a red light flashing twice (control unit or blocked duct?).
I tried it again today, and it ran for about 10 minutes, then stopped as before, but now it won’t power up at all. Plenty of power (12.8V) and gas.
Is there a fuse for this? If so, where is the fuse?
Any of the gurus have any ideas?
Thanks!

If you don't have the manual, here it is, may help...

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Perfect thanks, I don’t have the manual!