Audiobahn A2300HCX - Need Help!

[piersm2]

I have a Audiobahn A2300HCX amp and it all of a sudden quit putting sound to the subs. The blue light comes on and the cooling fans also do, but the gauges show no sound being output. I took it apart and cleaned it up thinking that some of the connections would have corrosion on them. After cleaning, I put it back together and tried it again. No luck. Is there anything else that I can do to fix this?

 

[Perry Babin]

Do you have a multimeter?

Can you power up the amp and measure voltage at various points if you're told where to measure the voltage?

 

[piersm2]

I need to buy another multimeter since the one i had broke. What would I measure? What would be needed on the multimeter in terms of voltage, current, etc?

 

[Perry Babin]

You don't need a meter that measures current. I'd recommend that you buy a used Fluke model, 10, 11 or 12 (in good working order) than any new, cheap meter. I used a Fluke 16 for about a week and it is also a good choice but the 10, 11 and 12 are better suited to car audio work. Auto-ranging is nice but not necessary.

 

[piersm2]

Could the amp be going into protection mode with the fans and the blue light still on?

 

[Perry Babin]

On the MA audio amps with the analog meters, the LED generally turns red if it goes into protect mode. It's likely that the power supply failed in some way.

 

[piersm2]

I was looking on your website and did all the tests: Checked shield on HU, Checked both remote and B+ wires, check shields on amp. All tests came back ok. What else should I do to try and figure out whats going on?

 

[Perry Babin]

You'd need to measure the DC voltage at several points inside the amp. Can you post a photo of the inside of the amp?

 

[piersm2]

Here are some pics of the inside of the amp:



RCA end of amp

B+, Ground, Speaker Output end of amp

I have bigger pictures on my computer but it would not let me upload them so I can e-mail them to you if that would be easier

 

[Perry Babin]

On the 16 pin IC near the center of the board, you need to measure the voltage on all 16 pins. The amp needs to be powered up (including remote). Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage. The attached image shows you the pin numbering scheme.

Do not let the probe slip and short between pins.

 

[piersm2]

These are the reading I got:
1-0.48V
2-4.92V
3-0.48V
4-0.48V
5-1.42V
6-3.33V
7-0V
8-.01V
9-0V
10-0V
11-.01V
12-10.81V
13-4.94V
14-4.94V
15-4.94V
16-0.13V

 

[piersm2]

The only cables i had hooked up were the B+, Remote, and GND

 

[Perry Babin]

There's a transistor (Q7P?) near the white connector near the 494. What is the DC voltage on its terminals (left to right, looking at the marked side of the transistor).

 

[piersm2]

The 3 pronged piece? I also realized that the fuses that go in the amp were not in when I measured the piece before. Will the voltages need to be re checked?

 

[Perry Babin]

Yes, the three terminal device.

You need to confirm that the voltages are the same after you reinstall the fuses.

 

[piersm2]

I plugged in the fuses and these are the readings I got:
1-.12V
2-1.17V
3-.05V
4-.12V
5-.02V
6-.01V
7-0V
8-2.4V
9-1.32V
10-1.25V
11-2.53V
12-1.67V
13-.85V
14-.76V
15-.7V
16-0V

I measured the three terminal device also. Going Left to right my readings were: 2.67V, the middle terminal decreased down to .06V then jumped back to .2V and went back down to .06V and repeated the previous, the last terminal read 2.67V also

 

[Perry Babin]

The voltage is too low for the amp to operate. How much current is your 12v power supply rated for?

 

[piersm2]

how do i figure that out?

 

[Perry Babin]

If you're using an AC-DC converter supply, it should state the rated current near the positive/negative terminals or somewhere on the front panel of the supply.

 

[piersm2]

I have it wired direct from the battery in my car.