Soundcraft UI12 Vol Pot

[spoontex]

Hi,

I need to replace one of the Main Mix potentiometer ( encoders? ) because they don't respond correctly and the touch it's to hard compared to the others. Anybody can help me to indentify this pot?



Thanks.

 

[sahib]

If it is rotating continuously then it is an encoder. Can you also post a picture of the underside of the PCB?

 

[spoontex]

They don't rotate continuosly. I attach video.

 

[sahib]

In which case they are Alps RK14 series stereo pots. And the value 103 normally stands for 10k. The letter C normally means C curve / reverse log but that normally would be in capital letter.

However, Can you measure the resistances as I have shown in the picture?

Top/bottom pins will give you the absolute value.

When viewed from the top, bring the wiper to the center and measure the resistance between the wiper and top pin, and wiper and bottom pin.

 

[NoisyIndividual]

I don't think your drawing is correct. 2nd and 3rd pins from the bottom are ground, bottom of each track.

 

[sahib]

Yes, you are quite right. I did not pay attention to that.

In which case, for the bottom half keep the wiper full right/CW and measure top and bottom pins for the absolute value.

Then bring the wiper to the centre and measure the wiper and bottom only.

However, as both pots will have the same value measuring the top half will also be sufficient.

 

[spoontex]

I measured and It's 10k and will be a audio tape. Because It's from Main Out, no?

 

[NoisyIndividual]

Not necessarily. Turn it half way and measure as suggested,, that will tell you for sure.

 

[NoisyIndividual]

Anyway, you will want to match it with the other output pot, so possibly consider replacing both. Then whatever law it has won't matter so much.

In fact, the headphones pot looks to be the same part, so you could swap that with the broken one and the law of the pot you can find to fit won't matter so much at all.

 

[spoontex]

I changed the pots, and the new ones fit perfect. But when I turn up the right level, a lot of pops starts. So I dissasembled again the board and I found IC 8068 that gets so hot! The advantage is that I can compare the voltages between left and right channels and the right channel has strange voltages on it. I traced this voltage and I found a short on another 8068 opamp. I dessoldered this one and the short was gone and this opamp out the board still have the short. Do you recommend me change both opamps? or only the one that fail?

Thanks.

The opamp is JRC 8068. I found this one:

https://www.mouser.es/ProductDetail...9wBY0jk0FO0zd-LbRXA9q7il2GrOaL8yqwfJUTKMIfskX