Potentiometer from 5k to 10k

[jfxwave]

I'm working on a Sony XM-1600GSD and the Filter said it needs a 12 pin 5k and I cannot find that anywhere from the USA to China. I stuck a 10k in its place would that be ok? I got the amp with rusted pots so I’m not sure how it sounded but after changing the Gain (6 pin 5k have it), Low Boost (6 pin 50k have it) and Filter (12 pin 5k did not have changed for 10k) the sound comes out playing very nice but the volume is very low to where I turn the stereo completely up and the gain all the way up and it’s like playing at level 2 maybe. Do you think the 10k might have done that? Remember I did not get a chance to hear this amp before I changed the pots. What might be the problem or where should I look? Thanks

 

[Perry Babin]

Is the test frequency well below the crossover frequency?

How does the signal level compare coming out of the preamp op-amp vs the output of the crossover op-amp?

 

[jfxwave]

I'm not sure if i'm testing this correct.
test frequency pin 1 is 96.8hz
signal level
preamp op-amp pin 1 = 3.83v
filter op-amp pin 1 = 2.06v
level op-amp pin 1 = 566mv

 

[Perry Babin]

Set the test tone to about 50Hz and the crossover pot fully clockwise and measure again.

Measure pins 1 and 7 on IC1, IC2, IC4 and IC5. Also measure the voltage on the RCA jacks with the probes on the shield and the center conductor on the back of the RCA jack. All of these are AC voltage.

 

[jfxwave]

Oscilloscope set on AC

IC1
Pin1 = 5.26v
Pin7 = 5.39v

IC2
Pin1 = 1.20v
Pin7 = 4.43v

IC4
Pin1 = 0.00v
Pin7 = 0.00v but flashes random numbers like 338mv, 409mv

IC5
Pin1 = 1.53v
Pin7 = 0.00v but flashes random numbers like 405mv, 280mv

RCA Input with 50Hz
Shield and the center conductor = 2.66v

 

[Perry Babin]

I don't understand why you have no signal on IC4.

Is the output greater at 50Hz?

Is the audio output clean?

Do you have ±15v on the power supply terminals of all of these op-amps?

 

[jfxwave]

it plays very clean no static or any type of interference.
IC1 stays at 50Hz

IC4 jumps around (video)

 

[jfxwave]

Sorry.
My power supply is 13.3v
I get 17.13v on all op-amps.

 

[Perry Babin]

Positive AND negative on the op-amps?

 

[jfxwave]

Yes, 17.+v on pin 8 positive and -17.+v on pin 4 negative on all op-amps.

 

[Perry Babin]

Do you have approximately 0v DC on all op-amp PS terminals other than pins 4 and 8?

 

[jfxwave]

IC1
pin 1 = 0.0v
pin 2 = 0.0v
pin 3 = 0.0v
pin 4 = -17.78v
pin 5 = 0.0v
pin 6 = 0.0v
pin 7 = 0.0v
pin 8 = 17.21v

IC2
pin 1 = -12.96v
pin 2 = -11.92v
pin 3 = -11.45v
pin 4 = -17.73v
pin 5 = -4.67v
pin 6 = -10.25v
pin 7 = -10.75v
pin 8 = 17.24v

IC4
pin 1 = 1.04v
pin 2 = 0.0v
pin 3 = 0.0v
pin 4 = -17.81v
pin 5 = -12.99v
pin 6 = -5.31v
pin 7 = -10.84v
pin 8 = 17.25v

IC5
pin 1 = 0.0v
pin 2 = 0.0v
pin 3 = 0.0v
pin 4 = -17.53v
pin 5 = 0.0v
pin 6 = 0.0v
pin 7 = 0.0v
pin 8 = 17.25v

 

[Perry Babin]

Is it possible that you could have some damaged vias on the pot that you replaced?

 

[jfxwave]

I changed all the pots and got the same reading.

Thanks for all the help and I learned a lot so thanks again. I'm going to set it aside for now and maybe in a week or so I will pull it back out and see.

 

[Perry Babin]

OK but that doesn't answer the questions about the vias.

 

[jfxwave]

Oh i'm sorry I should have told you that all vias were clean with no damage.
I double checked to make sure everything is getting to both side where need be.

 

[Perry Babin]

DCV on terminals 5, 6 and 7 of IC3?