Rockford power 550???? unknown

[terminatore]

so the good irf9540 and the irf540 too?

 

[terminatore]

hello i plugged in for a few seconds at 12 volt l amp started without burning a fuse of 5 ampere
at the hp output I have 50volts continuous and the mtp75n05 are burning

 

[Perry Babin]

Connect only remote and ground. What is the DC voltage on the gate leg/pad for each of the PS FETs?

 

[terminatore]

I do not connect the + battery?

 

[Perry Babin]

not for this

 

[terminatore]

mtp75n05 : 4.9 volts
mtp75n05 : 4.9 volts
irf9540 : 0.6 volts
irf540 : 0.48 volts
irf 9540 : 0.6 volts
irf540 : 0.48 volts

 

[Perry Babin]

4.9v seems to indicate that the drive circuit is OK.

Are all FETs back in the circuit?

Did you replace the defective ones?

Side note, the 75N05s are the only power supply FETs in this amp.

 

[terminatore]

all the transistors are soldered to the left of the amp view connector + and -
lower

on the right nothing is welded

 

[Perry Babin]

Did you replace the defective ones?

 

[terminatore]

I can desolder and redo the basic checks of the fets
as in your illustration

 

[Perry Babin]

Did you see the note in post #7 about posting images?

 

[terminatore]

you need pictures?

 

[Perry Babin]

Why aren't you posting the images as suggested?

 

[terminatore]

voila !

 

[Perry Babin]

Not viola. All wrong. Read post #7. I will not help any more until you post the images correctly.

 

[terminatore]

To upload photos, please do it as follows in the future:

Go Advanced
Manage Attachments
Browse
Upload

Repeat as necessary
Preview post to see how the post will look.
Click Submit Reply to send it to the forum.

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The reason I ask for a board number is because Rockford used the same board in multiple models. If you post the model number and I don't have anything under that model number, I won't find the relevant diagram which I may have under a different model number. As a side note, Rockford, in the past, has distributed diagrams for older amps if you email them.


See attached.

sorry I do not understand your message

here is your message number 7

I go with google translation

 

[terminatore]

Hello

I change everything: irf 3805 lm337 mur1620 and irf9540 irf540

the fuse of 10 amps burn!

the 2 capacitors 3300uF 50volts hs see photo

I have to remove the 2 capacitors: fuse ok

current consumption 1 amp

I always have the speaker output 27volts dc

measured voltage: only B + B- + remote

irf3805 g: 14 volts dc d: 27volts dc s: 27volts dc

irf540 g: 17 volts dc d: 27volts dc s: 26volts dc

lm337 Adj 24 volts dc Vin25 volts Vout: 27 volts dc

wall1620 pin 1 5volts Ac pin2 28volts Dc pin 3 5 volts Ac

thank you for your help (translated with google)

 

[Perry Babin]

IRF3805? Do you mean 3205?

Did you have the black meter probe on the main ground terminal of the amp when measuring voltage?

What is the voltage across the B+ and ground terminals?

Was it blowing the fuse when you had both rectifiers out of the circuit?

 

[terminatore]

yes excuse me irf3205
Yes, the tension on the main ground
yes battery voltage 13 volts
the fourth question I do not understand!

 

[Perry Babin]

Something is very wrong. With the black meter probe on the main ground terminal, you should read 0v to the source leg of the IRF3205s.

The MUR1620CT and MUR1620CTR are the rectifiers. Did you ever have both out of the circuit?