Get amp fixed or replace it?

We've got a Marantz 5.1 home theatre amp and it has been playing up recently - I posted a thread here a few weeks ago about the loud crackling / popping noise it was making and have since disconnected it and the sky box runs direct to the TV and not via the Marantz amp.

I did a factory reset on the amp and in the weekend we bought some smaller wharfedale speakers to replace the large floor standing ones that we are selling - but I turned the amp on and the same thing happened, so it's definitely an amp problem (I doubt the speaker wire would cause the problem as they've been working for 7+ yrs with no issues).

I spoke to the agent for Marantz yesterday and they said they can have a look at it and diagnose the problem and (hopefully) fix it. But they will charge a fee just to look at it, then the repair cost on top of that... so it could cost me over $200 to get it fixed... plus they are not open weekends and I'd have to take time off work to get there by 5pm

is it worth taking the amp to get fixed - or should I spend a bit more to get a newer one, or buy one on Trade me? - I've seen Sony, Pioneer and Denon amps on Trade me for under $300 and they are all good brands

it's a shame there is no-one on the North Shore Auckland who can fix Marantz amps

what would you do in this situation?