Rockford Fosgate Punch 250M2

[caraudioguy2100]

What i’m asking is D305,306,307,308 are all the same part number or different?

Since on the schematic it says SS-803

Is the SS803 a part number or what is what i’m asking

 

[Perry Babin]

The SS numbers are Rockford's internal part numbers.

The diodes are not the same. Look at the symbols. Two are switching diodes (like the 4148) and two are Zener diodes.

 

[caraudioguy2100]

Ok now I get it so D305 is a 4148 and 306 would be the 5231

I get it now . Thanks for taking the time to explain this to me .

I greatly appreciate your time

 

[caraudioguy2100]

The schematic that was given earlier in the post not sure if it matches up to this amp .

Does anyone have a schematic for this board number .

PC-0767-E

 

[Perry Babin]

I won't have anything closer. How is it different?

 

[caraudioguy2100]

Maybe not guess I’m getting tired tonight and over looking things .

 

[caraudioguy2100]

Back to this amp again .

I replaced every single transistor and diode in the channel checked the resistors all test fine .

I can get the channel to bias

The channel still has distorted output

 

[Perry Babin]

50Hz sine wave
4 or 8 ohm load
Photo of distorted waveform near clipping.

 

[caraudioguy2100]

Back to this amp once again .

My scope will not lock on to a sone wave for some reason still .


I’ve replaced all opamps all smd transistors and checked everything single resistor in that channel and everything test good .i still get distorted output and can’t figure out why .

If the rail caps for rush channel are going bad could that cause this issue ?

 

[caraudioguy2100]

What am I overlooking here .

I went through the entire channel 300 series parts ad everything that’s good .

I went through the entire preamp section everything tests good .

All of the 300 series diodes and transistors are brand new all of the components test good in the preamp section .

I still get distorted audio on the channel .

Should I remove one switch at a time and make solder bridges instead of the switches to see if one is bad ?

 

[caraudioguy2100]

I’m going through this amp again .

I think my issue may be a power supply issue and it’s affecting the output .

Do you happen to know what voltage I should have on the gate legs of the power supply fets ?

I’m only getting 0.40 volts on the gate legs for the fets is this normal or shoood I have near 5 volts ?

 

[Perry Babin]

Reduce the 12v power supply voltage and it's likely to go towards 5v.

 

[caraudioguy2100]

Do you have a pictures of the area around the 494?

R5,R3 according to the schematic are supposed to be 110k but in this amp someone put a different value something like a 90k resistor in those location wondering if it’s from the factory or someone else

 

[Perry Babin]

What's the input voltage on the regulators U5 and U6?

 

[caraudioguy2100]

18 volts

 

[Perry Babin]

This is a guess but it could be that the regulators were running too hot so they reduced the input voltage to 18v. Since the rail voltage is dependent on the 18/24v supply, they may have changed the resistor value to get the rail voltage back to where it should be. This assumes that you had the 12v supply voltage at the amp's terminals in the normal range (12-13.5v, give or take).

 

[caraudioguy2100]

If only half of the power supply fets were working correcly like only 1 bank could that cause the distorted audio in 1 channel ?

I have intermittent connections on 1 bank of power supply fets

 

[Perry Babin]

Possibly but not likely considering the amount of capacitance in the amp.

It should be an easy fix.

 

[caraudioguy2100]

Well I’ve been chasing a problem with distorted audio thought the issue was in e channel or preamp section .

I fixed the connections on the power supply fets and the amp has clean audio out of both channels .

Thanks for your help and patience with me throughout this repair I greatly appreciate it