Hifonics BXI-6000D

[Achim1409]

With 2ms no Signal possible, changed to 2us.

 

[Perry Babin]

Are you driving a low frequency sine wave into the amp?

Are the jumpers from pin 2-3 still in place?

 

[Achim1409]

50hz, jumper only on the changed one.

 

[Achim1409]

both jumper set, 200Hz sine

 

[Perry Babin]

The left image looks OK but I'd expect more amplitude. It may be good enough.

The right image is not going back to the negative rail.

How do the signals on the collectors of Q2 and Q7 compare?

 

[Achim1409]

same frequency.

 

[Perry Babin]

I don't think that's the collector.

 

[Achim1409]

yes, you are right. One Signal starts on center with 12v peak, the other starts 2,5v above center.

 

[Perry Babin]

Lift pin 1 of the driver IC that has the DC component to see if the drive signal again matches the good side.

 

[Achim1409]

yes, starts both at center, but the lifted one has 2,5v higher amplitude

 

[Perry Babin]

That would seem to indicate that the IC was driving DC back into the drive circuit which would generally mean it's defective.

 

[Achim1409]

Should i change it again?

 

[Perry Babin]

If you cannot find any difference between the drive circuits, I don't see any other option.

 

[Achim1409]

i changed the part. now its ok. Both start at center with same amplitude. What next?

 

[Perry Babin]

If you don't know about any other problems, remove the 10k resistor and the pin 2-3 jumpers to see if it will power up.

Remember to let all caps discharge before desoldering.

 

[Achim1409]

removed the bridge and resistor. Still the same. Relay not switching, DC between the inductors.
If i measure on the collectors without input i have a clean square with same amplitude on both.
If i measure on the fets, the working side has amplitude, the not working only dc. Maybe q2 defective?

 

[Perry Babin]

The drive signals were the same so I doubt that Q2 is defective.

Double-check all of the large resistors near the driver board.

 

[Achim1409]

Ok, i will check. Can i Use kst 92 for q2?

 

[Achim1409]

checked all resistors, ok. changed q2 (2D) against KST92, still the same. Mut be one more problem on the drive board. The Signal is not reaching first resistor in front of the board.

checked signal on pin 12, got dc. other 21844 on pin 12 good signal.

 

[Perry Babin]

Do you have signal on pin 6?