Arcam Delta 290 problems

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I was given a non-working Arcam Delta 290 amplifier S/No. 004919 recently having been told it keeps blowing fuses.

I have followed a thread with on this site about the same issue and believed I had the same problem as two existing contributors because the front two output transistors measured very low resistance.

However, having removed the faulty items and switched the unit on, the fuse does not blow but the power indicator light comes on and stays yellow. Apparently it should turn green after a while.

Does this mean the damage might be more extensive? If so, could anyone offer any suggestions about tracking it down further?

Many thanks in advance.
 
First off, email Arcam and request the service manual. They should give you a copy as PDF through the mail.

If the output MOSFETS have blown you will probably measure low resistance between all 3 pins. You need to do this with them out-of-circuit to be sure.

Check for a relay on the PCB connected to the speaker outputs. Make sure the contacts haven't welded - it's likely that they have.

This might be the kind of amp controlled by a microcontroller, especially if there is a remote control. It's possible that there's some damage there.
 
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