Kicker IX405d

[vincegironda]

Digital amp power supply

Q726 6.8v
Q725 6.83v
Q720 5.0v
Q721 5.02v

 

[Perry Babin]

I think Q82 may be defective.

There shouldn't be that much of a difference.

There is no digital amp. Class D doesn't mean digital.

 

[vincegironda]

I pulled vertical board where Q82 is located,
All 4 are A1266 PNP transistors.

Can I use any PNP transistor as a replacement?

 

[Perry Babin]

Post a photo of that board.

 

[vincegironda]

 

[vincegironda]

I already pulled Q82 and Q83, both were defective

 

[vincegironda]

Should I consider replacing Q80and Q81 too as Id'e prefer to avoid removing this board again?

 

[vincegironda]

I have 4 mpsa55 PNP transistors at hand can I use them in place of the A1266

 

[vincegironda]

So I used the MPSA 055 PNP transistors in place of the A1266'S. The gate drive voltage is now 5.88v on all the previously tested points.

The power led no longer switches to green.

 

[vincegironda]

Can I proceed with installing the new z44n's or wait until I have a scope to test first?

 

[vincegironda]

I think Q82 may be defective.

There shouldn't be that much of a difference.

There is no digital amp. Class D doesn't mean digital.

Thanks for the clarification Perry

 

[Perry Babin]

The pin configuration is different from the 2S transistor to the MPS, did you twist the legs to the right locations?

Does the back of the driver board show a darkening around the legs of the transistors like the front does?

Do you have any BD140 transistors?

 

[vincegironda]

I missed the difference in the leg configurations,
Hope I haven't damaged the transistors won't be making that mistake again.

The legs are quite long still so I should be able to desolder and twist to the correct locations.

 

[Perry Babin]

Does the back of the driver board show a darkening around the legs of the transistors like the front does?

 

[vincegironda]

I replaced the 4 A1266 transistors and the Z44's and the 4 channels are now working Thank you Perry.

What could have caused the A1266'S to fail in the first place?

 

[vincegironda]

Also I only noticed after removing the class d output transistors that there are 2 types. So before I order replacements do you know the placement of the irf 640 and irf 9640's please?

 

[Perry Babin]

KICKER IX405D Service Manual download, schematics, eeprom, repair info for electronics experts

 

[vincegironda]

Thanks again

 

[vincegironda]

So I finally got around to replacing the blown transistors,
Upon powering up it tripped my power supply.

The z44n's were showing as short between the drain and source. When I removed them the amp powered up fine?

 

[Perry Babin]

Were they shorted when checked out of the board?