MXR EVH 5150 chorus

[The Gator]

Thought I would share some gut pics of this thing. Friend of mine but it used and says it makes a lot of noise. So he gave it to me to try and see if I could figure out what was wrong with it. So far I haven't figured out what it is. It kind of hisses and crackles. Still makes chorus effect.

 

[The Gator]

I can't say I like it much, but I am not much for chorus anyway. I like the walrus audio Julia circuit, but do not use chorus on stage.

 

[Nostradoomus]

Well I’d start with the uhhhhhh….hmmm.

 

[The Gator]

Yeah LOL. I looked over it with the magnifying glass pretty good. That is a lot of solder points though. I don't think it's a bad ground connection but it might be. I don't particularly like the design very much. It kind of sounds like a capacitor issue. I'm going to dig through my parts and pieces and see if I have the mn3005 chip somewhere. That's an easy swap, although probably not the problem.

 

[darwin999]

Wow, a very complex pedal - makes it tough...

At the very least, I would visually inspect all parts & solder connections that receive physical stress - stompswitch, jacks, pots. Perhaps touch/apply a little pressure to those connections carefully w/ a small tool or tweezers, looking for a loose connection. Verify that the in/out jacks are ok - i.e., clean connecting pins, not dirty, not bent. And look closely at that ribbon connector to the stompswitch - signs of wear, bad connections, etc. It doesn't look like there's any PCB cracks...

Did you search online (@ MXR Forum, DIY stompbox forum, etc) for others with the same problem?

 

[The Gator]

As I suspected, the xvive Ic was the culprit. Replaced it, and the signal to noise ratio is now proper. I have to say though I'm not much for this thing. I feel like the Julius circuit is much more to my liking. Either way at least I was able to fix this crazy thing for him.