Hifonics Zues XI

seankane · 2012-12-17 9:04 am

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 · 2012-12-17 7:22 pm

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

Check the drive signal before installing the power supply FETs.

seankane · 2012-12-17 8:55 pm

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 · 2012-12-17 9:10 pm

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 · 2012-12-17 9:52 pm

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

Check your e-mail Perry.

seankane · 2012-12-25 8:31 pm

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 · 2012-12-30 10:31 am

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 · 2012-12-30 10:44 am

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

seankane · 2013-01-03 5:16 am

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 · 2013-01-03 5:53 am

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.

seankane · 2013-01-03 7:39 am

Pins 9 and 10 do not have a square wave on them.

Perry Babin · 2013-01-03 8:18 am

Post the DC voltage on all pins of the IC.

seankane · 2013-01-03 8:40 pm

As I was testing pin #8 on the 494 something on the back of the driver board smoked.

There is 2 transistors Q81 and Q82. The say CY 210 on them, any ideas of what they are?

The amp does not power up now. It does nothing like its totally dead.

Perry Babin · 2013-01-03 10:06 pm

Possibly a KTC4373.

I think they are QB1 and QB2.

seankane · 2013-01-04 6:22 am

Wonder if I could sub the 2SD1898's I have.

Same pin configuration, both npn.

Collector-base current: little lower 100v/vs/120v
Collector-emitter current: little lower 80v/vs/120v
Emitter-base current: same
Collector current: higher
Collector power dissapation: higher
Junction temp: same

What do you think?

Perry Babin · 2013-01-04 6:38 am

They would probably work but I don't know how they're being used in the circuit so be careful when powering up the amp.

seankane · 2013-01-04 6:48 am

OK well they must do alot because if they have failed everything to the 494 is dead. The amp does nothing, totally dead. I am going to remove them and check them out.

Wierd thing is, as soon as I metered pin #8 on the 494 the back of the driver board smoked and everything went dead instantly, no current draw no nothing. Its like somebody just turned a light switch off.

seankane · 2013-01-04 6:54 am

Here is a front and back pick of the pwm board. You can see the 2 transistors on the back of the board. This is a pretty old amp.

Perry Babin · 2013-01-04 7:09 am

Are you getting B+ and remote voltage to the driver board? Look at the attached image if you can't read them on your board.

seankane · 2013-01-04 7:16 am

No I am not, maybe I should be checking QP10,11,12???

Hifonics Zues XI

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