Boss DM3 restoration, noise and static

[sgmezei]

I posted on diystomp and didn't receive any replies. Even after I bumped it. Maybe somebody here can lend a hand.

A buddy gave me his boss DM3 to fix. It has a static noise buildup that goes away if you shake it or lift it it up and put it down. The delay sounds great and works well. The noise does not cut out the output. I checked the solder joints, jacks, and pots and do not see anything wrong yet. Everything is tight and not shorting out that I can see.

Is this common? I have an old DM2 and have not had this issue.

Could it be that the electrolytic caps are worn out?
I just wanted to get another opinion before I start replacing the electrolytics. There is like 25 of them......

Also, if I do do that, there are some super low polarized values I havent seen before. Like 0.1 uf electrolytic. Is it alright to use a "normal" film cap here?

Thanks team!

[jkokura]

Could it be that the electrolytic caps are worn out?
I just wanted to get another opinion before I start replacing the electrolytics. There is like 25 of them......

Also, if I do do that, there are some super low polarized values I havent seen before. Like 0.1 uf electrolytic. Is it alright to use a "normal" film cap here?

Scott, your conclusion is the first thing I thought of. Electrolytics wear weird from all I've come to understand. I'm not a Boss technician, but what you're describing sounds just what amps that need caps replaced sound like.

Yes, you can replace any electrolytic with Film caps. The problem with film caps is that you can't get them in reasonable sizes or prices when you get above 1uF, so that's why we still use electrolytic at values that high. You can also use Tantalum if you find them in the right values.

What I would do is get out the trusty audio probe and follow the signal path while the effect is exhibiting the issue. You will hear where the fizz is introduced. Start replacing caps just before it starts. Or, replace all of them.

Jacob