Amp 6 Power supply problem

[shzmm@hotmail.com]

Hello I have an AMP6 here I have been putting together. Everything was going swimmingly until the very end. Testing was fine I got the green led on, power was good. Then I made a mistake. It seems the voltage regulator was touching the heat sink. Anyways something smoked so I replaced both the rectifier and regulator. Now when speakers are connected I get a motorboating sound so I presume the chip may be damaged. The green led also does not come on any longer. I tried to bypass the regular power supply with a 12VDC source but nothing changes.
I have triple checked all connections diode and capacitor orientation. Could I really have destroyed the chip that easily?

Thank you for your replies

[Scratchy]

Sorry to hear about your misfortune.
As you know now, the AI states that the VR must be electrically isolated from the heatsink.

Do you have the amp inputs shorted when testing?
It's possible the amp is going in and out of protection mode, giving the motorboating sound you hear.

Yes it is possible to destroy the chip that easily:

Blown-chip.jpg

[shzmm@hotmail.com]

ok Thank you for your reply. So how do I go about testing the unit? You talk about protection mode but I'm sorry I don't know what that means. Do I need a new chip or not is what I would like to know? Is there a standard route of testing these amps?
As to the issue of the heatsink yes you are right the instructions say that it should not touch the heatsink, unfortunately I found the screw I used to connect the two was slightly too big and it tore the little plastic insulator. Of course I should have tested continuity...
My luck with these amps is not very good I have to say.