Problem with Alpine 3544

[JoergST]

Hello I got an alpine 3544 amplifier and it doesn´t work.
The problem is, that the amplifier doesn´t turn on.
There is no voltage at the µPC494C and the transistors in the amplifier area hasn´t got there voltage.

The only voltage that i can measure is at the transistor in the power supply area. with 12,80V.
I have got an 13,9V with 10A power supply to connect it to the 3544 alpine amplifier.
And I conact the remote cable, but nothing happen.
Does somebody has got an idea. If you want photos I can upload someone.

Anybody a service manual for this amplifier?
Regards Jörg

 

[Perry Babin]

Q813 is the switching transistor that delivers power to the 494. That would be the first place to check for voltage.


Email me and I'll send you the schematic.

babin_perry@yahoo.com

 

[JoergST]

Perry you are great!!!!!!

The q813 was defect but it was not to 100% defect. The way B und C was defect. B and E works.
I must order a new transistor and than i hope it will work.
Regards Jörg

 

[bmwpowere36m3]

Hi, Perry do you still have a schematic around for this amplifier. Mine basically starts up, indicator light goes from orange to green and then a second later blows both onboard 30A fuses. I have it opened up, but I don't see anything obvious...

Anything I should check for or any tips would be great.

 

[Perry Babin]

It sounds like it has shorted output transistors.

Email me if you want the schematic diagram.

babin_perry@yahoo.com

 

[bmwpowere36m3]

Thanks for the schematic, so looking at it... the output transistors would be under "Power Stage," labeled: "Q505-Q516" (2SC3421, 2SC3182, 2SA1358, 2SA1265 devices).

 

[Perry Babin]

Q509-q516

 

[bmwpowere36m3]

Q509-q516

Awesome, will checking them while in the circuit via a DMM (diode check) be sufficient?

 

[jol50]

Yes look for shorts, if you don't find any check the outputs...the other large transistors on the sink. Note the rectifiers may normally show a short.

 

[bmwpowere36m3]

Well, I pulled all the output transistors and 1 output transistor tested bad (shorted), good thing I removed them because in circuit they all tested bad

The other transistors on the heat-sinks tested fine, but the diode rectifiers show a short in two positions. For one, they both are shorted on the outside pins A-C (my understanding that's normal due to being connected to the transformer). Second, on D802 & D801 there's a short A-B.

If the diode/s blew wouldn't it cause more damage?

 

[Perry Babin]

D801 and D802 shouldn't show a short across legs 1 and 2. They should show a short (in the board) from 1-3. Out of the board, no legs should be shorted together.

If the diodes are not shorted, reinstall all of the transistors except the defective one, clamp all semiconductors down and power it up through a 10 amp fuse. Does the fuse blow?

If the fuse doesn't blow, does it produce audio (at a low volume level)?

 

[bmwpowere36m3]

D801 and D802 shouldn't show a short across legs 1 and 2. They should show a short (in the board) from 1-3. Out of the board, no legs should be shorted together.

If the diodes are not shorted, reinstall all of the transistors except the defective one, clamp all semiconductors down and power it up through a 10 amp fuse. Does the fuse blow?

If the fuse doesn't blow, does it produce audio (at a low volume level)?

Okay, the diodes tested fine when removed (no shorts)... however the board still has shorts. Been are the readings at the pads of the diodes:

Pads 1-3: 0.4 ohms
Pads 2-3: 0.0 ohms
Pads 1-4: 0.4 ohms
Pads 4-6: 0.4 ohms
Pads 5-6: 0.0 ohms

(Pads X-Y is a pair)

 

[Perry Babin]

2-3 and 5-6 shouldn't be shorted. Clean the flux off of the board to see if you have a solder bridge between pads.

If I'm not mistaken, the rest are connected through traces or transformer windings so they will read as a short.

 

[bmwpowere36m3]

2-3 and 5-6 shouldn't be shorted. Clean the flux off of the board to see if you have a solder bridge between pads.

If I'm not mistaken, the rest are connected through traces or transformer windings so they will read as a short.

Yea, it's messy, but their not connected with a solder bridge. Those were the same pins that were shorted when the diodes were still in place along with another pair of pins (that connect through the transformer).

 

[Perry Babin]

You could have a shorted rail capacitor. Another possible cause could be a transistor that's shorted to the heatsink. Confirm that no tabs of any audio transistors read anything near 0 ohms to the heatsink.

I'm assuming that you don't have the amp connected to anything.

 

[bmwpowere36m3]

You could have a shorted rail capacitor. Another possible cause could be a transistor that's shorted to the heatsink. Confirm that no tabs of any audio transistors read anything near 0 ohms to the heatsink.

I'm assuming that you don't have the amp connected to anything.

Nope the PCB is pulled from the amp, and here's the schematic with the pins highlighted, attached. When I measured the diodes, ALL of the audio power transistors were removed, the only ones remaining on the board are: Q507, Q503, Q505, Q508, Q504, Q506, and Q801-810.

 

[Perry Babin]

I would suggest that you remove the rail caps to eliminate them from the possible causes. The rarely short but there's not much left that could cause a short between those terminals.

 

[bmwpowere36m3]

I would suggest that you remove the rail caps to eliminate them from the possible causes. The rarely short but there's not much left that could cause a short between those terminals.

That would be E890, E801, and E802 (the last two being the Big 6800uF caps).

 

[Perry Babin]

yes

 

[chewby31]

Hi Perry Babin, do you still have schema for the ampli alpine 3544?
My problem is my ampli is in protect when the rca are connect and when they are not connect the light of the ampli is green...
do you know where is my problem?