Rockford punch 600a4

[rhempz01]

Just came in and was only drawing .56amps of current, stuck in protection. All the buz272/buz21 check good. Power supply is good. So I found a few driver transistors were missing from the board. I replaced them and now it draws 1.81amps of current and rear channel are working and the front does not unless in 2channel mode I get a crazy looking signal only on the fleft.

 

[Perry Babin]

Broken RCA shields?

 

[rhempz01]

I'll check, perry. I don't think so I can see the 50hrtz u300 going in but not out. And I think u400 appears burnt.

 

[rhempz01]

Perry do you know what those parts are lm3?? Are the dual op amps? They are faded off. Lm358?

 

[Perry Babin]

What's the PC# on the board? The similar diagrams I have show TL072 in all locations but the attached photo has LM833s.

 

[rhempz01]

Do you think the tl072 will work if I replace them all? I will haft to pull both data sheets to see what the differences are.

 

[Perry Babin]

With op-amps, the datasheets may not be 100% reliable in determining what will/won't be compatible. In this amp, the TL072 will likely be OK. If nothing else, they will be OK for testing.

Make sure the regulated voltage is not excessive before replacing any of the op-amps.

 

[rhempz01]

If I change them, would I need to change them all or just the damaged components?

 

[Perry Babin]

I don't know what caused the damage. If the regs failed and drove full rail to all of them, reliability may be an issue with all of them. I'd start by replacing the ones known to be defective.

 

[rhempz01]

They are all testing ok to me. It drawing current now so I believe the mosfets on the front side are bad in the output section. In place if the buz21/buz272, use irfp540 and irfp9540? I'm changing the drivers first maybe some are leaking

 

[Perry Babin]

What about the bias setting?

 

[rhempz01]

That's what it was I backed them all down a quarter turn. It only goes up to 2.85amps when I push the 5v 40hrtz tone into the front side. The rear two channels I don't have the signal on the two 10ohm resistors or anywhere past u40, it goes up to the switches but not to the output transistors.

 

[Perry Babin]

What's the PC# on the board?

 

[rhempz01]

PC-1984-H

 

[Perry Babin]

I don't have it. See if you can get it from Rockford.

 

[rhempz01]

Ok

 

[motronix]

What do you need from this list? (if you need)

 

[rhempz01]

Pc-1984-H the highlighted scheme. Thanks

 

[motronix]

Try this

 

[rhempz01]

Thanks. I got it working now. All channels are clear. Pots are set correctly. Thanks.