Hello all.
I have an RF 400.4 on the bench, all powers up fine and stable current draw. No overheating.
The problem is with the front channel, it's picking up noise from the cd source unit, you can hear the cd tracking when loading and skipping the disc.
The reach channel has clean audio and doesn't pick up any interference.
I've tried switching the rca's, earthing the rca shields to the head unit, using the same earth for head unit and amp. I've also repaired loose rca input solder joints and cleaned crossover and gain pots so far.
When I turn the front gain down the noise reduces but when it's turned up its very apparent.
All 4 rail caps are bulging.
Any help appreciated, thank you
I have an RF 400.4 on the bench, all powers up fine and stable current draw. No overheating.
The problem is with the front channel, it's picking up noise from the cd source unit, you can hear the cd tracking when loading and skipping the disc.
The reach channel has clean audio and doesn't pick up any interference.
I've tried switching the rca's, earthing the rca shields to the head unit, using the same earth for head unit and amp. I've also repaired loose rca input solder joints and cleaned crossover and gain pots so far.
When I turn the front gain down the noise reduces but when it's turned up its very apparent.
All 4 rail caps are bulging.
Any help appreciated, thank you
Attachments
I don't see anything wrong with the caps. Generally, the shrink-wrap causes the cap to bulge but if it's raised, you can easily push the cap down flat.
Resistance from all RCA shields (no RCAs plugged in) to the main ground? Check all 4 inputs.
Resistance from all RCA shields (no RCAs plugged in) to the main ground? Check all 4 inputs.
Thank you Perry
Readings in ohm's
Right front 000.3
Left front 000.6 fluctuates up and down
Right rear 1001.6
Left rear. 1001.4
Readings in ohm's
Right front 000.3
Left front 000.6 fluctuates up and down
Right rear 1001.6
Left rear. 1001.4
That prevents the amp from cancelling noise and will cause engine noise in the car. Replace it. Does it solve your problem?
Perfect Perry, clean audio on all channels now.
The diode was cracked, what could have caused the failure
The diode was cracked, what could have caused the failure
Typically because 12v contacted the RCA shields. You need to check the RCA shield ground for the head unit. They also get burned when this happens (but generally when the diode or a trace in the amp opens).