Hifonics BXI 2010 D

[Perry Babin]

The second one should read near 1k like the first one.

 

[mike49504]

SHould i try replacing it again? If i pull it out of the board and measure from the pad to ground i get 1K ohms

 

[Perry Babin]

Does the transistor appear defective?

Was it new?

Did you check it for leakage?

 

[mike49504]

It was new. And it tests fine.

 

[Perry Babin]

You'll have to determine what's causing the difference.

Does it have two 1k ohm resistors near the driver board?

Do you read ~800 ohms across each of them?

 

[mike49504]

I tested it again and theres leakage between the legs. Im thinking something is causing them to go bad. I will test the components in that area.

 

[Perry Babin]

Check several of the unused transistors. Maybe you got a bad batch.

 

[mike49504]

Ok i put another 1 in and have 1K on both of them now and .465K from emitter to ground on both. Power amp up and the fets get red hot still.

 

[Perry Babin]

Did you check it again after you powered it up?

Do the drivers get hot?

 

[mike49504]

Drivers dont get hot.

They still measure 1K And both have 3.96 volts on the 3rd leg to ground

 

[Perry Babin]

Does the emitter voltage match now?

Does the waveforms on the gates look the same now?

 

[mike49504]

emitter voltages match now. Wave form is no better on half the fets

 

[Perry Babin]

The current draw seems to be greater than the waveform would cause. Have you tried twisting/pushing/pulling on the transformer to see if the current draw decreased?

Do any wires on the transformer appear to have overheated?

 

[mike49504]

Tryed twisting pulling on transformers no change. None appear to have been overheated. DOnt understand this is what i have for the wave forms

 

[Perry Babin]

Did you measure the resistance across two 1k resistors near the driver board?

 

[mike49504]

1 measures 1.001K
other one:0.994K

 

[Perry Babin]

In the amp I have here (similar, not exact), those resistors read 800 ohms. I'll have to try to determine what's in parallel with them. It will be some time tomorrow before I get a chance to do it.

For the last two waveforms, it appears that the left signal is driving the FETs off but it's not well controlled. The one on the right appears that it's not switching any FETs off.

Measure the resistance from the non-FET side of the gate resistors to ground. What resistance do you read?

Do this for all FETs in case there's a break in the circuit.

 

[mike49504]

0.465K on all of them to ground

 

[Perry Babin]

There are 2 diodes for each bank of FETs. Desolder one leg of one diode from each pair. Does that eliminate the high current draw?

You may want to do one at a time to see which pair is causing the problem.

 

[mike49504]

Pulled all 8 of them (1 side of the diode) 1 at a time. Still draws 10 amps of current. The fets heat up, the regulators heat up some resistors in the output section heatup. even with the rectifiers removed.