DS18 H-K08

[caraudioguy2100]

Well I still have a problem with the power supply in this amp .

Not all of f the banks of fets have drive signal on them

 

[Perry Babin]

Starting at the 494, where is it lost between there and the FETs?

 

[caraudioguy2100]

Pin 5 of one of the 4427’s

 

[Perry Babin]

What's between the output pins of the 4427 (5 and 7) and the gate resistors?

 

[caraudioguy2100]

There is a 4.7 ohm resistor a 10’ohm gate resistors and then the gate leg of the fet .

There is also a diode that connects to the gate leg of the fet

 

[Perry Babin]

The signal should be passing the signal if they're in series and neither goes to ground.

You stated that 'not all banks' have drive. What's the resistance from the gate leg to the source leg for the ones with signal and the ones without?

 

[caraudioguy2100]

They all
Measure 0.598 K

Pic 1 is the bank that has good drive signal and pic 2 is the one that doesn’t have good drive

Scope set to 5us 5 volts div

 

[Perry Babin]

Do you have the same drive signal out of pins 5 and 7 of the 4427s?

 

[caraudioguy2100]

This amp uses 2 IR4427’s

Pic 1 and 2 show the drive on pins 5,7 of 1 4427

Pic 3 and 4 show the drive on pins 5,7 of the other 4427 where I get the bad drive

 

[Perry Babin]

Does the second IC have the same input signal as the first one?

Does the second IC have B+ supply voltage?

 

[caraudioguy2100]

Both ic’s have 12 volts on pin 6

And both ic’s have the same signal on pin 2

 

[Perry Babin]

Did you replace the IC with low output?

 

[caraudioguy2100]

I replaced it but I think it may be defective .

Are these sensitive to heat like the IR21844’s?

 

[Perry Babin]

I've never seen one fail from heat but I've always tried to use as little heat as possible with SMD ICs.

 

[caraudioguy2100]

Switched the ic it a slip better but still has issues .

 

[caraudioguy2100]

My phone auto corrected on the last post I didn’t proof read and it doesn’t make sense .

Anyway

Q226 you said often fails in these amps .

The original is 2SA1037 can I replace it with a MMBTA56?

 

[caraudioguy2100]

Ok I figured this amp out finally on to the next one now .

The problem with the amp is when the power supply fets blew it took the driver ic’s with it . Also there are 2 4.7 ohm resistors that connect to pin 6 of the driver ic’s and they open when the power supply blows . It also takes out Q226

Hope this helps others

 

[caraudioguy2100]

Back to this amp .

The amp worked for awhile and the outputs blew again .

The original outputs are not available right now .

The original outputs are FDH45N50

Wondering if the FDH50N50 might work ?