Audiopipe AP 3000 1D

[Perry Babin]

Is that signal on either of the outputs of the LM219 on the driver board, right now?

Are the rectifiers in or out of the circuit?

 

[caraudioguy2100]

Rectifiers are in circuit do I need to take them back out for testing

 

[Perry Babin]

The high frequency 80k hertz

Is that signal on either of the outputs of the LM219 on the driver board, right now?

 

[caraudioguy2100]

No

 

[Perry Babin]

If you drive a 50-100Hz signal into the amp, how far does that signal make it through the amp? To the outputs? To the driver board?

Testing without the rectifiers is safer. Discharge the rail caps if you're going to remove them.

 

[caraudioguy2100]

Went back through the amp replaced the optocouplers

The problem is I get no drive signal on both banks of outputs .

Any ideas where to start checking since both banks of outputs have no drive signal on them

 

[Perry Babin]

Pull the rectifiers.

Do you get the 80kHz signal back?

If not, drive a strong 50-100Hz signal into the amp and see if the signal (low frequency) returns.

 

[caraudioguy2100]

I noticed a bad driver for the outputs .

Is there a sub I can use for the 2N4401 and 4403?

 

[Perry Babin]

I tried the MMBTA06/56 and the amp wasn't happy. I had to use the originals.

One of these board may have the 4401/3s in the power supply. Something like the A06/56 will work in the power supply so you could swap them to get the drivers if you don't want to wait on ordering them.

 

[caraudioguy2100]

After replacing the divers with original part numbers and the 2 optocouplers on 1 board this is the drive signals I get in the high and low side outputs

Do these drive signals appear good or do I have a problem somewhere still ?

Scope settings are 5us 5volts/div

 

[caraudioguy2100]

Here is a picture of the audio driverboard .

Do you know what ic controls the drive signal for the outputs ?

There is something defective on the driverboard which is causing 1 board to have no drive signal to the outputs .

I swapped audio driverboard a and the amp has drive signal on the outputs but this audioboard makes the amp have no drive signal

 

[Perry Babin]

All of the components have to pass their respective signals. Start by posting the voltage on the header. A marginal voltage there may let one board work where the other won't.

Before pulling the working board, make a note of all pins of all ICs that have the 80kHz square or triangle waveform (no audio input).

 

[caraudioguy2100]

Voltage on the header of both boards

Non working board

Pin 1:-4.61
Pin 2:0.00
Pin 3:0.00
Pin 4:-12.97
Pin 5:12.97
Pin 6:0.11
Pin 7:5.00
Pin 8:0.00
Pin 9:5.00
Pin 10:0.21
Pin 11:4.66

Working board

Pin 1:0.00
Pin 2:0.00
Pin 3:0.00
Pin 4:-13.10
Pin 5:12.86
Pin 6:0.11
Pin 7:0.11
Pin 8:0.00
Pin 9:4.99
Pin 10:0.21
Pin 11:0.19

 

[Perry Babin]

It's likely U704 that's defective.

 

[caraudioguy2100]

Do you know what part number U704 is ?

The ones in this amp are defaced

 

[Perry Babin]

These should be right. You can't trust the build houses nowadays. They've been known to have the wrong numbers printed on the ICs and they look normal.

 

[caraudioguy2100]

Thanks for the info I will order the 219 and see what I come up with

Also the small ic is a 4560 correct ?

 

[Perry Babin]

Yes.

 

[caraudioguy2100]

I’m working on this amp again replacing the lm219.

I noticed that neither board has drive signal on the outputs again .

I ordered new optocouplers .

1 set of optocouplers says
Lite-on high speed optocoupler 10MBd

The other set says
10Mbd open collector high speed optocoupler.

Are these the same pretty much or wondering what one I should use in this amp

 

[Perry Babin]

If the optocouplers have the right part number and you purchased them from a reputable distributor (not ebay), either should be OK.

The drive starts with the 4560. Do you have a triangle waveform on pin 1 of that IC on the driver boards?