Alpine MRV-1507

[seankane]

I read mike49504's post but couldnt find a burned trace at least not yet??

Same issue, channel 1 plays and channel 2 is dead. When I switch the 0/180 channel 2 plays and channel 1 is dead.

mike49504 or anyone know where this broken trace could be?

 

[Perry Babin]

Do you have audio on pins 2 and 8 of IC401?

If you operate all of the other switches through their entire range, does audio ever play through the dead channel?

 

[seankane]

Got this amp for repair.

Powers up green then power LED flashes on and off red.
Music light is green.
Protetion light is amber or red.

There is no voltage on the gates of the IRFZ48 p/s fets.

There is no rail voltage coming from the rectifiers.

Pic#1 power supply
Pic#2 output stage

Any ideas?

 

[seankane]

Do you have audio on pins 2 and 8 of IC401?

If you operate all of the other switches through their entire range, does audio ever play through the dead channel?

Im sorry Perry this amp is a MRV-1505. Same same? Still need the same info?

 

[seankane]

I made 2 different post and somehow this became one post??

I dont get it??

I want to focus on the MRV-1507 that I posted the 2 pics of. I will start a new thread on the MRV-1505.

 

[seankane]

Disregard ALL posts except post #3. Please read post #3 and we can go from there.

 

[Perry Babin]

What happened from post 1 to post 3? The amp was initially playing. Is it now not playing?

 

[seankane]

No these are 2 different amps. The original post was suppose be for a MRV-1505 but I screwed up and called it a MRV-1507.

When I made the post on the MRV-1507 (#3) somehow the seperate post became one post? I dont know?

The MRV-1505 has the issue with each channel working and not working when the 0/180 phase switch is switched and the MRV-1507 has the issues from post #3.

I asked a moderator to delete the posts, but they said they would have to delete the whole thread. So I figured we could just start from post #3 and focus on the MRV-1507.

Pic#1 power supply
Pic#2 output stage

 

[Perry Babin]

If you disconnect the 6 pin connector from the board, does the power supply power up?

 

[seankane]

No the power and the protection light are flashing red.

 

[Perry Babin]

Does it at any time produce pulses on the gates or drains of the power supply FETs?

 

[seankane]

The drains remain at supply voltage, the gates have about 0.356 vdc on them.

I didnt notice any pulsing.

 

[Perry Babin]

Post the DC voltage on all pins of IC602.

 

[seankane]

Im sorry Perry I dont find an IC602 on the board?

Is it on the bottom side of the board?

I see an IC206 but its on the output side of the board and I have the 6 pin wire unplugged still?

 

[Perry Babin]

Yes. It's on the bottom of the board. It's one of the 494s.

 

[seankane]

Will it be safe to power the amp out of the sink disconnected from the output board upside down?

 

[seankane]

I see 2 494's one says IC601 and one says IC605.

Shall I take readings from both?

Do I use the battery terminal or direct battery terminal or both when powering this amp?

When I power the amp its like it starts to power up drawing a few amps of current then drops to nothing on the meter of my supply.

 

[Perry Babin]

You can use either terminal.

The IC602 is printed mirror image, if you look closely.

 

[seankane]

IC601

1: 0.967
2: 0.963
3: 3.850
4: 0.221
5: 1.668
6: 1.670
7: 0.004
8: 14.53
9: 0.410
10: 0.427
11: 14.53
12: 14.53
13: 5.05
14: 5.05
15: 5.05
16: 0.004

IC605

1: 0.954
2: 0.952
3: 3.873
4: 0.220
5: 1.674
6: 3.762
7: 0.004
8: 14.53
9: 0.433
10: 0.428
11: 14.53
12: 14.53
13: 5.05
14: 5.05
15: 5.05
16: 0.003

 

[Perry Babin]

Reduce the supply voltage to about 13.5v. Does that help?