Audison SR1Dk output driver card, no High-side output

[Perry Babin]

Did you compare the readings on the board (optocoupler out) between 5 and 8 on the two boards?

 

[Maxikill97]

Yes, as I remember, both rode OL

 

[Perry Babin]

How are they reading different if both optocouplers read the same and the boards read the same?

 

[Maxikill97]

Thats the weird part. One time it rode OK, other time it had a much lower resistance.
You know what, I am going to take apart the other amp and compare both boards.

I will re-measure and put the values in my next post.

 

[Maxikill97]

Normal polarity is: HCPL3180 high side Black probe on Pin5 and red probe on Pin8

*High side Optocouplers in the board:*

-Good board normal polarity. Starts with 1Kohm, then rises to 6Mohm, then slowly sinks to 0.597Mohm
-Bad board OL

Probes reversed polarity.
-Good board sticks at 248Kohm
-Bad board sinks from OL to 18.5Mohm

*High side optocouplers out of the board*

Board vias good polarity:
- bad board, Starts with 1Kohm, then rises to 30Mohm, then slowly sinks to 3Mohm
- good board, starts with 1Kohm and rises to 25Mohm

Board vias reversed polarity:
-Bad board, sinks down from 40Mohm to 6Mohm
-Good board, sinks down from 40Mohm to 20Mohm

HCPL3180 out of the board, all measurements between Pin5 and Pin8 rode OL

 

[Perry Babin]

Have you tried installing the good board optocouplers in the bad driver board to see if the bad board works properly?

What is the brand name of the optocouplers that you're using?

Have you tried the FOD3120?

 

[Maxikill97]

Not yet, I will try to switch tommorow
The optocouplers are from Broadcom.

The only optocouplers I have ordered/needed yet are 6N137 and HCPL3180.

 

[Maxikill97]

Bad board won't work properly with the good optocouplers in. Amplifier went into protect.
Good board with 'bad' optocouplers didn't work either

 

[Perry Babin]

With the new optocouplers, do you still have the same strange readings (compared to a good board) on the optocoupler as you did previously?

Did you look at the board with a bright backlight to see if there are any darkened areas?

 

[Maxikill97]

What a stupid driver boards.
I ordered the FOD3120 you mentioned, and yes! It fixed the bad driver board.
Putted the good HCPL3180 back in the good driver board, now that board has the excact same issue.
The good board even blew the 2D driver transistor.
So, again changed the driver transistor, LM219, putted in a 100% good working HCPL3180 and FOD3120 insteas. still the same issue.

This time, only the high-side fets get hot

 

[Perry Babin]

Wasn't the original optocoupler an FOD3180?

 

[Maxikill97]

Yes, you are right, the original optocouplers I putted back were FOD3180. I could not get the FOD3180 back then.
I found a new website previous week, and they have a FOD3180.
I will order and try those.

 

[Maxikill97]

The FOD3180 arrived.
I soldered in a new MMBTA92 driver transistor on the driver board, new LM219, new FOD3180.
Amplifier does not startup properly and pulls a lot of current.
Only the high side fets get hot and both High and low side fets are not driven properly.
The duty cycle seems about 7-10% when pausing the scope screen.

Input square wave to the driver board is clean.

 

[Perry Babin]

Is it accurate to say that you only have one board that won't work with any of the optocouplers? Or did the bad board work with the FOD3120s?

 

[Maxikill97]

The bad board did not work with FOD3120 and HCPL3180 either.
I think it's accurate to say that.

 

[Perry Babin]

There may be no saving that board if you cannot find how it differs from the working boards.

Are the good boards new or are they pulled from working amps?