ok so after installing a new 494 chip the amp will power up and seem to be fully functional but after I power the amp off and on for a 2nd time the chip is dead and the amp goes straight into protect
Are you saying that the 494 fails or that it is simply not producing output pulses because the amp is in protect?
Ok so I got the amp up and running but there is a strange issue. When I power it up at first it starts up fine and plays audio but when I shut it off and power it up again it goes straight into protect and won't power up normally til the rail caps fully discharge.
Does the rail voltage reach the maximum voltage before the oscillation starts? Like this:
http://www.bcae1.com/temp/ampstartup01.mkv
http://www.bcae1.com/temp/ampstartup01.mkv
It will only power up if the voltage is below 12.5v. anything above that and it goes into protect. Once its on it operates at 14.4v but will not power up at 14.4v.
Check the voltage on all terminals of the comparator on the PS driver board while ramping the voltage up from 12v to 14.4v. Do any change?
When I power this amp up it works fine but when I remove the remote I get a pulse of about +20vdc on the drain of the low side preventing the output section from starting until the +20v goes away. Any ideas whats going on?
How long does it take to drain off?
There are two 5w 2.2k resistors in some of these amps that will drain off the voltage. Are they within tolerance?
There are two 5w 2.2k resistors in some of these amps that will drain off the voltage. Are they within tolerance?
How long does it take for the rail voltage to drop below 20v?
Do you read the 20v across each of those resistors?
Do you read the 20v across each of those resistors?
Are the resistors that you're referring to connected between the output filter inductors and the secondary ground?