Hifonics BXI-6000D

[Achim1409]

The Fets marked in the Picture, but on the 1Ohm resistor close to the drive board i have the same signal. The disconnected cable is normally connected to the center leg of the right mosfet.

 

[Perry Babin]

That wire goes to both the feedback circuit and the circuit that helps build the supply voltage for the high-side of the IC.

Do you have the same signal on pin 6 of the 21844 as you showed for the 'bad' drive signal?

 

[Achim1409]

No, on Pin 6 is a good signal

 

[Perry Babin]

Does pin 6 go to the gate resistors of other 3 outputs on that side? (away from the driver board)

 

[Achim1409]

yes. And there is a good signal

 

[Perry Babin]

The high side of that IC has no supply voltage. Confirm by measuring the voltage across the high-side filter cap.

If there is no voltage, a 9v battery can be used to supply voltage to the cap.

 

[Achim1409]

on that four caps i have 10V DC on each. Maybe its necessary to insert the fets?

 

[Perry Babin]

The high-side capacitor is connected across pins 11 and 13 of the 21844.

 

[Achim1409]

ok, on that i have 0V. How is the polarty for the 9V?

 

[Perry Babin]

Pin 13 should be positive (very carefully) confirm on other IC.

 

[Achim1409]

if i connect a 9V Battery the sawtooth signal is disorted.

 

[Perry Babin]

Is the voltage on the 9v battery being pulled down?

 

[Achim1409]

No, not pulled down. If i start the amp with the battery allready connected, i have no more drive signal on both sides. Also it seems no voltage. The oscy is staying in center.

 

[Perry Babin]

If you have the tutorial, I'd suggest going to a low-voltage power source (last item in the 'type 3 page of the tutoria)l. It involves removing the rectifiers and adding windings to one transformer. It's much safer and you can test with all components in the circuit with little chance of damaging them.

 

[Achim1409]

yes, i have since 2 days. but a lot to read. i will try later.

 

[Achim1409]

So, i have tried with fets inside, but than there is at this side no signal at all. If i connect the 9V batterie, there is no change, also the battery is not dropping.
I dont understand, how the 10v are generated. I have compared the values of the working side with the not working one, but there are no big differences.
According IRS Datasheet, VB(13) is connected with a capacitor to VS(11). VS is on the center pin of mosfet low side. 13 should over a diode connected to vcc.

 

[Perry Babin]

Just to confirm, do you still have a good signal on pin 6 and the FETs that are driven by pin 6?

The Vs pin is connected to the low side drain and the high-side source. The high-side drive circuit floats. Did you reconnect the wire that you removed?

 

[Achim1409]

The cable is reconnected. on Pin 6 i have no more signal. On Pin1 the signal is much weaker as on pin 1 working side.

 

[Perry Babin]

Is the signal strong on the driven side of the 10k resistor that connects the drive circuit to pin 1?

 

[Achim1409]

Yes it is. Much stronger. MEasured the value of that resistor. 9,5k