Hifonics Zues XI

[seankane]

I received this amp for repair.

The amp powers up and seems stable and produces audio......however upon opening it there were only 2 p/s fets installed.

I get a square wave on all the gate resistor pads but some have big squares and some have small squares.

I am going to put new p/s fets in and see what happens.

I noticed a spot on the board that is brown from heat behind the pwm board from a component in location QP7 and is marked B631K and there is a resistor inline with it that burned in position RP18. I am not sure of the resistance it should be because I cant identify it.

Anyone have one of these lying around that could help me?

[Perry Babin]

Are RP17 and RP18 serving the same purpose in two identical circuits?

Check the drive signal before installing the power supply FETs.

[seankane]

I have checked the gate drive signal, some of the pads have a nice large square wave, and some of the pads have a nice small square wave. Why is there different sizes in waves between gate pads?

Those 2 resistors appear to be similair circuits but are different color and I believe different values.

[Perry Babin]

How do you define large and small? Pulse width? Square wave?

If the difference is amplitude, what is the amplitude of the large and small?

[seankane]

I will have to check when I get home, leaving for work.

Check your e-mail Perry.

[seankane]

Replaced the burnt resistor and the 2SB631K and the supply has a nice square wave. I installed 4 out of the 10 p/s fets and the amp powers up and is stable. As soon as I get the parts for this amp and the BXi2610D I should have them both up and running.

[seankane]

I installed the remaining 6 p/s fets and I now no longer have a square wave.

The amp powers up and is not in protect. There is a hissing noise from somehwere in the power supply. I viewed the drive circuit through the scope while powering the amp and it starts to go square then loses it.

Anything I am missing?

[Perry Babin]

Do you still have a square wave on the output pins of the driver IC for the power supply?

[seankane]

This PWM board uses a KIA494AF controller.

According to the datasheet I looked up it says pin #13 is the output controller, and ouput #1 is pin #8 and output #2 is pin #11.

Is this correct?

So I need to view the signal on pins 8 and 11?

The pin configuration is all mixed up on the data sheet an unlike a TL494C is this also correct?

[Perry Babin]

Pins 8, 9, 10 and 11 are all terminals of the internal NPN driver transistors. Most amps use 9 and 10 as the outputs but MTX and a few others use pins 8 and 11.

This amp uses pins 9 and 10 as the output pins.