Yamaha m1516 gain switch intermittent

[bmaughan]

Hi, I have a Yamaha m1516 that seems to have an issue with the gain switches. If the switch is in a position for a while it doesn’t pass signal. If I blast it with a lot of level it will come back on, or if I exercise the switch a bunch it will work as well. As far as I can tell this is probably because there’s some dc on the switch causing excessive carbon build up. ? Sound like I’m on the right track?
If this is the case I’m curious which caps may be the first and most obvious culprits causing this issue. I’m a bit hesitant to do a full recap for many reasons but honestly I’m digging the sound so much right now I’d like to change as little as possible. .. but I’d also like switches that work every time haha.
I attached an input channel schematic if someone smarter than me has any interest in taking a look I would be super grateful!

 

[JohnRoberts]

Sounds like an oxidized switch contact... high voltage (loud signal) can punch through the thin oxide layer. Ideally if practical replace the switch.

I don't have any experience using magic goo but if the switch needs replacing you probably can't make it worse.

JR

 

[bmaughan]

I've tried cleaning the switch using the standard type stuff and if I recall correctly the problem goes away for a bit but ends up returning. So I'm wrong to assume dc on the switch? this is good(ish) news I guess....

 

[JohnRoberts]

yup... not DC but oxidation of switch contacts.

JR

 

[mmicha]

I also have this same exact mixer and I have a few channels (3) that are also experiencing this issue. I’ve done the same thing, using some contact cleaner and exercising the gain switch but that only helped briefly. I really really like this mixer, I added 16 CAPI output transformers and it just sounds great. My plan is to replace the gain switches during my next mod, but I’m not sure what gain switch I could use to replace them.

 

[bmaughan]

I have 16 direct out using capi xfrms as well! Killer setup.. mind you I was coming from a sphere eclipse console and downsized to this and honestly the only thing I miss about the sphere are the eqs.. the Yamaha eqs SUCK. Even with the lcr circuit mods.. they’re still eh..
I started another thread where someone was using some in quad right inductors doing a 712 type thing.. no seems to know anything about that mod.

 

[mmicha]

Yeaaa the EQ mod as the next mod I planned on doing. I really don’t like the synth EQs currently sound and that’s really something I’m in need of. Yea I’ve never heard the 712 EQ mod on this mixer before.

Did you find any replacement gain switches for the 1516?