[FredHedgecoth]

I am doing a (hopefully) minor repair on a Yamaha MX12/4 audio mixer. An NJM4580 is being replaced but some traces are burned and I’m not sure where the jump wires should go. If someone can tell me which endpoints go together I may be able to whoop this puppy. I am also attaching the service manual to assist.
The one I’m baffled by is pin 2 - ? I tried to attach the service manual for this model so anyone that can read it might be able to assist me here but it is too large. The link for it is found at

https://www.manualslib.com/download/4138818/Yamaha-Mx12-4.html.

This section of the circuit board controls the Group 1 & 2 controls between sliders 4 and 5 from right.
Here are the connections as best I can determine them:

pin 1 - node 16

pin 2 - node ?

pin 3 - node 15

pin 4 - node 13 & 14 (?)

pin 5 - node 12

pin 6 - node 11

pin 7 - node 10

pin 8 - node 9

As you can tell, I am a novice with experience limited to simple soldering and continuity testing. If anyone can direct me further with this project it may save a useful piece of equipment from the dump. Many thanks!

 

[danadak]

This manual might help,

Dropbox

www.dropbox.com

 

[FredHedgecoth]

Thanks…but I’ve given up on this project. My soldering skills are weak and my patience level is apparently near zero. I hate scrapping an otherwise decent piece of equipment but a professional repair costs more than a replacement.

 

[Martaine2005]

Such a shame as it would have been an easy fix providing nothing else was fried.
Look at the component side and reference designators for each component. Then look at the component layout in the service manual that @danadak linked to.
It will be easy to see which connections are required.

 

[FredHedgecoth]

Agreed…a shame to toss but my skills are lacking and the space is pretty tight as well. I’ll hang on to the unit and maybe give it another shot when I’m not feeling so frustrated!

 

[FredHedgecoth]

BTW, a tech quoted me $150 to do the repair. Would you say that was about right?

 

[Martaine2005]

That depends.
If it’s a half hour strip down, half hour repair and half hour reassembly, that’s probably not bad. But for a few jumper wires and a SIL preamp and just the board in front of the tech, that’s a lot.
Ask if you can do all the donkey work and he does the soldering.

 

[FredHedgecoth]

That depends.
If it’s a half hour strip down, half hour repair and half hour reassembly, that’s probably not bad. But for a few jumper wires and a SIL preamp and just the board in front of the tech, that’s a lot.
Ask if you can do all the donkey work and he does the soldering.

I had told him that I had disassembled everything and the board was ready to work on but I think he was just pricing the job high to avoid having to do it. If i try my hand at the repair again should I use insulated wire for the jumps rather than bare wire? It's really tight (for me) in there and my soldering gun is a standard Weller hobby gun so the tip is a bit clunky. Wah, wah, wah...sorry to be griping about it.

 

[Martaine2005]

You can use bare wire. The traces and connections are not insulated. Be mindful of bending the wire where the original track was. Enamelled copper wire is better though.
Some techs would do a nice job of repairing the board using eyelets in the holes. These get pressed in and make great connections.