GK MB500 -- has anybody seen this failure mode?

[RHFusillo]

I have a Gallien Krueger MB500, purchased about 18 months ago. Today, the amp failed and I cannot find anything on the web that describes this problem.

The amplifier produces no sound. The "halo" pilot light that surrounds the on/off switch is dark, even when the switch is pushed in. The "-10 db" switch is lit solid red, whether that switch is pushed in or not.

I powered the unit completely off and left it for about an hour, but the same thing happened when I tried to power it back on.

There is no weird smell that would indicate fried electronics.

I figure that I will have to send the amp back to GK for warranty repair, but I am curious about how serious the problem is.

 

[B-string]

Have you unplugged it, let it sit and tried a different outlet? Unplug the speaker cable incase it shorted? I would imagine it would have to be a power supply (SMPS) failure.

 

[RHFusillo]

Thanks for your reply, B-string. The answer to each of your questions is yes.

 

[B-string]

Thanks for your reply, B-string. The answer to each of your questions is yes.

Sounds like a random failure in the units power supply then. Most good SMPS will self check when plugged in and not latch "on" if a failure is detected (protects other parts of the amp). Contact [email protected] for an RMA and shipping instructions.

 

[rajprods]

The exact issue you described happened to me in the middle of a gig last Saturday. Can you state what the issue was? Did it happen again after it was repaired?

I have a Gallien Krueger MB500, purchased about 18 months ago. Today, the amp failed and I cannot find anything on the web that describes this problem.

The amplifier produces no sound. The "halo" pilot light that surrounds the on/off switch is dark, even when the switch is pushed in. The "-10 db" switch is lit solid red, whether that switch is pushed in or not.

I powered the unit completely off and left it for about an hour, but the same thing happened when I tried to power it back on.

There is no weird smell that would indicate fried electronics.

I figure that I will have to send the amp back to GK for warranty repair, but I am curious about how serious the problem is.