Rockford Prime R600x5

[Perry Babin]

That seems like a preamp level problem. Bad solders connections are possible but not likely. It's almost always a problem with a bad switch.

Are the preamp components also designated in 4 groups (1xx-4xx) like the output section?

 

[Frycztech]

The preamp section is the vertical board with the crossovers and level controls or the board with the RCA inputs?

 

[Perry Babin]

Yes

 

[Frycztech]

Here are some pictures that I took

 

[Perry Babin]

I don't see anything definitive or familiar. The only way to find the break in the signal would be to drive a single channel at a time and map out the output pins of the op-amps that have signal for each channel. You'd do this in full range mode.

I'd suggest that you make something similar to the attached image (fine tipped dental probe used as a meter probe) to prevent shorting between pins, especially when probing pin 7 (output pins of the ICs are 1 and 7 for the njm2068 op-amps).

 

[Frycztech]

Ok so iam putting a audio signal into a single channel and then testing the each pin on all the 2068's? And am I grounding one pin of my meter?

 

[Perry Babin]

You only need to check pins 1 and 7 for signal.

If you're using a signal source grounded to the 12v power supply, you can use the primary (main) ground for the black meter probe location.

 

[Frycztech]

Am I checking for AC voltage?

 

[Perry Babin]

AC

Don't mis-label any. It will make finding the fault nearly impossible if you mix the channel/IC/pin when mapping the signals.

 

[Frycztech]

The values iam getting are fluctuating. It that normal? Some of the ppin 7's have capacitors in front of them and iam not sure how to get to them. I dont want to damage anything shorting anything out.

 

[Perry Babin]

Use a sinewave instead of audio.

 

[Frycztech]

Dose a 1khz since wave work?

 

[Perry Babin]

1k will work but a lower frequency may be better since some multimeters have limited bandwidth. The following is a 100Hz test tone.
http://www.bcae1.com/temp/100hz300seconds.zip

 

[Frycztech]

Perry,

So far this is what I got. Pin 7 is hard to get to one these because the input board sits on top of these and I dont want to short anything out like you said. If these reads dont help I will try to get pin 7.

u4- pin1 0.800
u5- pin1 0.142
u6- pin1 0.328
u7- pin1 0.762
u8- pin1 0.800
u9- pin1 0.968
u21- pin1 0.776

 

[Perry Babin]

You don't need to post the voltages at this point. What you're trying to do is find the output pins that correspond to the various channels.

Make sure that there is no audio from the (good) channels, other than the one you are driving. If you're getting near 1v on the driven channel, I'd expect less than 1/10th of a volt on the non-driven channels.

 

[Frycztech]

When you are measuring the 1v is that on the output or on the op amps?

 

[Perry Babin]

On the op-amps. You need to drive enough signal into the amp to get good signal at the op-amps (like you found on U7, 8, 9). The output on the speaker level (when driving a working channel) will likely be clipping hard.

 

[Frycztech]

So I need to have close to 1vac on the working output channels and then measure the op amps?

 

[Perry Babin]

You need to have enough input signal to be able to see the difference between the channel being driven and the non-driven channels. The exact voltage doesn't matter.

 

[Frycztech]

Ok how will i know when I have enough voltage? Put a speaker on it and listen to the volume?