Alpine MRV-1507

seankane · 2013-01-03 6:09 am

No it didnt.

This is a pic of the gate drive signal, 10us 5vd

Perry Babin · 2013-01-03 6:14 am

I don't see a problem with that. If you measure the DC voltage from center leg to center leg of the two rectifiers on each side, what is the DC voltage?

seankane · 2013-01-03 6:17 am

-50 vdc on both sides.

If the signal looks good, and its producing rail, why wont it power why does the power light just flash red?

Perry Babin · 2013-01-03 6:25 am

Are all of the connections between the two boards intact?

seankane · 2013-01-03 6:40 am

They are now.

Perry Babin · 2013-01-03 6:42 am

Does the amp produce audio?

seankane · 2013-01-03 6:53 am

It tries to sometimes, there is pulsing DC everywhere.

Its on the output terminals, the drains, gates, and sources of the outputs have bouncing DC that all over the place, maybe when the amp is trying to turn on and off?

I cant get any consistant readings I can see audio for seconds on 1 channel then it goes away and I am getting DC spikes on the other channel.

I dont know??

Perry Babin · 2013-01-03 6:55 am

It could be that the channel with DC is causing it to go into protect. Double0check the outputs.

seankane · 2013-01-03 7:04 am

OK I will check the outputs in the channel with DC spikes. That makes sense because the channel has audio until the other one spikes the it loses it.

seankane · 2013-01-03 7:22 am

I removed all the outputs to test them and thought I would power the amp.

Same result the amp powers green, just starts drawing current then flashes red and the one channel is geeting DC spikes of up to 12 vdc.

Any ideas?

Perry Babin · 2013-01-03 7:24 am

Are you measuring across the speaker terminals?

Post a photo of the components in the channel with DC.

seankane · 2013-01-03 7:50 am

Yes across the speaker terminals.

This is a photo of the half of the output board that is giving me trouble.

Perry Babin · 2013-01-03 8:17 am

Connect a dummy load across the speaker terminals. Does that stop the DC and allow the amp to power up or does the amp draw excessive current?

seankane · 2013-01-03 8:22 am

Connecting a 4 ohm dummy load allows the amp to power up and be stable with solid green light but the red protection light is flashing.

The pulsing DC is gone as well.

Perry Babin · 2013-01-03 8:25 am

Did you find any outputs that were shorted or leaky?

seankane · 2013-01-03 8:34 am

I have not tested them yet, why does the dummy load remove the DC and allow the amp to power?

Is the red protection light flashing because the outputs are removed?

Perry Babin · 2013-01-03 8:40 am

The DC source causing the DC on the speaker terminals without the outputs likely has significant resistance. If not, it would cause the amp to draw excessive current.

The red LED blinking may be a separate problem.

seankane · 2013-01-03 8:45 am

2 outputs were shorted and 2 were leaking from that channel.

Could a defective driver be causing the DC source?

Why does the dummy load get rid of the DC and allow the amp to power?

seankane · 2013-01-03 8:54 am

Q419 a C2682 has full rail on every leg.

Q420 a C2682 does not from the other channel.

In the picture they are the 2 components that are screwed down to the heat sink still where the fets clamp down.

Just poking around and thought I would mention it??

Perry Babin · 2013-01-03 9:02 am

You can't rely on DC voltage with the outputs out of the channel.

Alpine MRV-1507

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