Rockford Fosgate 600.5

[Perry Babin]

20v/div and 2mS/div.

I don't think the 540Ns are causing the problems you're having at this point.

 

[mike49504]

No voltage on the second set and no square wave on the sec set of rectifiers

 

[Perry Babin]

Can you post a photo of the windings on the transformer (where they go into the board)?

 

[mike49504]

Heres the pics of the windings

 

[mike49504]

heres another one also

 

[Perry Babin]

Did you see the square wave and DC with the scope on the first set of rectifiers?

 

[mike49504]

No gate wave on the first set either. Only place i have a gate wave is on the power supply fets

 

[Perry Babin]

With your multimeter, confirm that you have ~2.3v DC on pins 1 and 2 of the 494. Also confirm that you have rail voltage on the first set of rectifiers.

If you have those, the peak to peak voltage on the rectifiers may be too much for the settings you used on the scope. Set it to the highest v/div and make sure that you have the probe set to 10x (if it has a switch). If you see horizontal lines above and below the reference line, turn the vertical amplifier to whatever it takes to get those vertical lines to ~±3 vertical divisions. Then turn the timebase until you have ~3-4 cycles on the display. This basic procedure is something you'll have to do on may repairs so try to remember it.

 

[mike49504]

I think i have bad rectifiers in this amp i started testing like u said and now i only have voltage on 1 rectifier from the first set and voltage on 1 of the other set im gonna change them out and retest

 

[IsakAlexander]

I have the same one here with broken Q25, Would I need a 100W soldering gun to remove it from the heat sink? What is the differences on these 540´s?

 

[Perry Babin]

Start a new thread.

Confirm that the circuit board designation for the transistor is correct.

Post the PC-# for the circuit board that you have.