Kicker IX1302

[m4ick]

Q703

B: 5.7v
C: 0v
E: 4.41v

Q704

B: 4.41v
C: 2.7v
E: 5v

 

[Perry Babin]

Are you sure that you have the pins labeled correctly? They appear to be reversed. The pin configuration, left to right is ECB.

 

[m4ick]

Yes, they are backwards. Post #41 is correct.

 

[Perry Babin]

With the base higher than the emitter for Q703, Q703 should not be conducting so it should not be pulling the base of Q704 down. If you reinstall all of the parts but leave Q703 out, does the amp produce audio?

 

[m4ick]

Yes.

 

[m4ick]

It does produce audio without Q703 but something I noticed when I was testing voltages was when my probe slipped I touched the emitter of Q703 to a resistor tied to ground, it came out of protect and stayed out of protect until I switched it off and back on.

When that happened the emitter jumped to 5v.

 

[Perry Babin]

Do you have a different PNP transistor (different part number) that you can install in place of the 1266 for Q703?

 

[m4ick]

Apparently, when the above happened, I had shorted Base to Emitter on Q703 for a split second, all of the voltages came up normal after that until I shut it down and turn it on again.

 

[m4ick]

I have 1023s and the mouser equivalent to the 1023s.

 

[Perry Babin]

Try one of those in place of Q703 to see if the amp will operate properly.

 

[m4ick]

No, exact same symptoms. This is getting a little crazy.

 

[m4ick]

And still, if I short Base to Emitter it powers up and stays on until I shut it off. Seems once I introduce a full 5.7v to the emitter, it stays at 5v afterwards.

 

[Perry Babin]

Other than the emitter of Q703, R708 and R709, is there anything connected to the base of Q704?

 

[m4ick]

I think you mean Q704.

C725 is connected base to emitter on Q704.

EDIT: I see, you said 704, sorry.

 

[Perry Babin]

Remove the cap, reinstall the rest of the transistors and see if the amp works properly.

 

[m4ick]

I revisited this amp today. It originally had k2312s in the PS, I was using Z46Ns and it was having issues powering up. I tried 3205s (1 per bank) and it powered up. I populated the PS with Z46Ns and it did not power up. I got to thinking maybe had to do with the gate charge, the gate resistors were only 10ohms, I thought they were 100 but misread.

It went from not powering up with 8 Z46Ns and 10ohm gate resistors to powering up with Z46Ns and 47ohm gate resistors. Could that have been the wild goose I've been chasing?

 

[Perry Babin]

There's nothing about the components that you listed that would have prevented it from powering up. The value of the gate resistors is important for long term reliability but with 10 or 100 ohm with the Z46s, it would have powered up.

Are you sure that you're changing the gate resistors? They would have one end directly connected to the gate of the FET and the other end directly connected to the emitter of the driver transistor.

 

[m4ick]

Yes, I'm sure. They all tested 10ohms +-.1ohm. Maybe it had a bad solder joint that I didn't catch.

It sounds great, too. It seems like with it all the way up it doesn't distort at all on my highs, which I thought was strange but the sound quality is great.