Rockford power 550???? unknown

[terminatore]

I reread the output of irf3205:

G: 9 volts dc: 12volts dc S: 0 volts dc

irf9540: g: 14 volts dc d: 27volts dc s: 27volts dc

the MUR1620CT did not clean out cuicuit

reread: pin 1 5volts Ac pin2 28volts Dc pin 3 5 volts Ac

(sorry I did a copy pasted with google translation and irf3805 replaced irf9540)

 

[terminatore]

I have all desoldering
check all the components
the mur1620ctr hs change
the lm317 hs change
I have all welded

new measure voice by voice:

B + 13Vdc

black probe on B-

no fuse burn

current 1 amp

Q110 irf540: 1: -28Vdc 2: 0Vdc 3: -28 Vdc
Q111 irf9540: 1 + 28Vdc 2: 0v dc 3: + 28Vdc

Q210 irf540: 1 -28Vdc 2: 0Vdc 3: -28Vdc
Q211 IRF9540: 1 + 28VDC 2: 0VDC 3 + 28VDC

Q311irf9540: 1 + 28Vdc 2: -28Vdc 3: + 28Vdc very hot
Q310 irf540: 1-28Vdc 2: -28Vdc 3: -28Vdc very hot

Q411 irf9540: 1 + 28Vdc 2: 0Vdc 3: + 28Vdc
Q410 irf540: 1: -28Vdc 2: 0Vdc 3: -28Vdc

U3 lm317: 1: 13Vdc 2: 14Vdc 3: 27Vdc

D8 mur1620tc: 1: -5 Vac 2: + 27Vdc 3: + 5Vac

U4 lm337: 1: -12Vdc 2: -28Vdc 3-13Vdc

D9 mur1620ctr: 1: 5Vac 2: -28Vdc 3: 5Vac

Q6 irf3805: + 5.8Vdc 2: + 12.85Vdc 3: 0Vdc
Q8 irf3805: +5 Vdc 2: + 14Vdc 3: 0Vdc
Q7: irf3805: + 5Vdc 2: 13Vdc 3: 0Vdc
Q5 irf3805: + 5Vdc 2: + 13Vdc 3: 0Vdc

I have a speaker output the 3 that comes out 27 Vdc


(sorry translated with google)

 

[Perry Babin]

You need to check the components that drive the outputs in the defective channel.

The voltages need higher resolution to be useful. Post the exact reading on your meter. If it reads 28.24v, post 28.24, not 28.

 

[terminatore]

measure B + 12.98 V dc

Q310 irf540: 1: -28.00V dc 2: -28.03Vdc 3: -28.03Vdc

Q311 irf9540: 1: + 28.77Vdc 2: -27.96Vdc 3: + 27.70Vdc

speaker output -27.79 Vdc

 

[Perry Babin]

Are you sure that Q310 is OK (not shorted or leaking)?

 

[terminatore]

Hello

I checked: Q310 irf540: HS

verified: Q311irf9540: HS

solder 2 new Q310 and Q311

the irf540 Q310 in 10 seconds it gets very hot and hs


then the Q311irf9540 heats less but hs too

weld 2 new Q310 and Q311 not connect to B + waiting for your help thank you

 

[Perry Babin]

Set the bias pot fully CCW for that channel.

Did you check the gate resistors and the driver transistors driving those FETs?

 

[terminatore]

well I'm going to turn counter-clockwise for bias adjustment

for verifivation I am not where are these FET drivers or grid resistance!

 

[Perry Babin]

The components will be the 300 series parts. The values of the resistors are marked on each resistor. The SMD transistors are checked like any other bipolar transistor.

 

[terminatore]

there are 15 bipolar serie 300 I have all the unsolders for the verifiers?

the resistances too?

 

[Perry Babin]

You don't initially have to desolder any of them. The driver transistors are Q308 and Q309.

 

[terminatore]

very good
I start with the bias adjustment

and Bipolar Verification starts with Q308 and Q309

 

[terminatore]

Hello

all the resistors r135 r148 r248 r235 r335 r348 r448 and r435 the same value 10 ohm

for the measurement of the bipolar I removed them from the cuicuit:

Q308 npn: CE + - OL. EC: - + 0.65V. EB: - + OL. CB: - + OL (HS)

Q309 pnp: CE + - OL. CE: - + OL. CB: + - 0.65V. BE: - + 0.65V (good)

 

[terminatore]

sorry for waiting component out of stock

mpsa06 mounted the amp starts

4 outputs work without distortion

fuse ok

the irf are hot

how does one regulate the bias?

my supplier offered me equivalents for the same price:

obsolete irf9540: equivalent irf5210
obsolete irf540: equivalent irf3415

 

[Perry Babin]

I don't know if the subs will work.

Did you readjust the bias current?

 

[terminatore]

I do not adjust the bias

I do not do it

 

[Perry Babin]

The replacement output transistors are rarely identical (operating parameters) to the originals so you virtually always have to readjust the bias.

This how I adjust it:
http://www.bcae1.com/temp/ausettingbias.swf

 

[terminatore]

thank you
but I do not have or put the probes ampermeter on this amp to adjust the bias using the potentiometer
if you have an example?

 

[Perry Babin]

Are you saying that you do not have an amp meter in series with the amp?

Do you have a large 2 ohm resistor (dummy load or one you use to limit current)? Lower values will also work for this.

 

[terminatore]

hello Perry Babin

I have a fluke 179 and a fluke 16
for the load resistance a 6 ohm 5 watt