Rocford punch 500-2 2007 model.

[rhempz01]

Opened the case and all four ps fets blown and rectifiers were burnt also the source leg on them is black. I don't know how to test them?

 

[Perry Babin]

Rectifiers don't have a 'source'. Anodes and cathodes. Look up the datasheet.

If the center leg isn't shorted to the outer legs, they're likely OK. To test more definitively, you have to remove them. They rarely fail.

 

[rhempz01]

Thats what i have read time and time again, they were burnt into the casing (black behind them, ill remove them. Do you know what part these ps fets are perry? i cant make them out the legs are completly detached and blown? the 34r resistors are ok?

 

[rhempz01]

not sure how to word it, the compound was blackened all behind the d1000-d1001, as was the middle leg of d1001. so i pulled the blown ps fets, all were shorted. That's is far as i got so far and tested around resistance.

 

[Perry Babin]

What is the number on the face of the PS FETs? Likely HUF75344G.

The rectifiers are soldered to the MEHSA insulator. Desolder all 12 legs for the components and remove the entire assembly.

 

[rhempz01]

ok, and that's the ps fets i ordered. Once removed, ill check them for a short, and post back.

 

[rhempz01]

Man, what type of soder is used on these amps its so hard to remove it....? Anyway no shorts in any of the rectifiers?

 

[Perry Babin]

Normal lead-free solder.

What make/model iron are you using?

 

[rhempz01]

I have like a china youde 856+ Maybe it was just old i added soder to it and got it hot and got it out, but it was tuff. no shorts should i do any further testing?

 

[rhempz01]

im also looking for the top cover for one of these amps if anyone has one the want to part with........

 

[rhempz01]

I recieved the ps fets and the installed them, With resisted current it doesnt power up, only a clicking sound coming from the upper right, i only left the current on for a second or two. Should i read the same resistance on all the ps fets 1-3 ect....?

 

[Perry Babin]

With only remote and ground connected (no B+), Post the DC voltage for every power supply FET measured 1-3 (black on 3).

 

[rhempz01]

Ok so I have
Q1000 9.03v
Q1090 9.02v
Q1001 .704v
Q1091 .709v

 

[Perry Babin]

What do you read on pins 9 and 10 of the LT494 on the power supply driver board?

 

[rhempz01]

9: 11.53v
10: 11.44v

 

[Perry Babin]

Confirm that your meter reads approximately 1.5v on pin 5 of the 494.

 

[rhempz01]

1.519

 

[Perry Babin]

The drivers , Q103, 104, 105 and 106 on the river board will need to be replaced.

If you remove them, you should read about 5v on pins 9 and 10. After replacing the drivers, you should read approximately the same on the gate legs of the power supply FETs.

Do NOT connect B+ to the amp until you get good driver voltage at the FETs.

 

[rhempz01]

Ok thanks Perry do you know that part number off hand? If not I'll find it. Thanks again

 

[Perry Babin]

MMBT3904 MMBT3906

Without chipquik, these driver boards are VERY difficult to remove without damaging the vias in the main board. If I remember correctly, the drivers are difficult to replace with the driver board in place. Having solder paste and a right-angle soldering iron tip may make it possible.