What's the deal with 2.0mm DC jacks?

[Mark Hammer]

I'm fixing/modding a friend's Boss OD-1.  Wallwarts with  2.1mm plugs do not power it up, and also wiggle when inserted.  They're just not snug.  However, given the age of the pedal, I think the DC jack has gotten tarnished inside and needs replacing.  I looked around for  a replacement to slide into the slot, and found the replacement that Small Bear sells, listed as 2.0mm centre pin.

So here's my question:   Will 2.1mm plugs "work" on 2.0mm jacks?   Are they different?  functionally equivalent?  Were early-issue Boss pedals using something unique that required their adaptors?

I'm confused.

[Rob Strand]

I've had this happen to me too.  Other times you plug a 2.5mm which is clearly wrong and it works.

They're just not snug. 
and I think the DC jack has gotten tarnished inside and needs replacing

Those items two are the key.  When the effect side gets old the outer spring contact doesn't extend out as much as it did. When you put in the larger diameter plug the holes are offset and the offset is just enough not to contact.
You would think the spring would make it connect but it doesn't. You should be able to wiggle it a bit  but I remember once, to my disbelief, even that didn't work.

[blackieNYC]

I did have to replace one that was obviously tarnished.  I got one from Smallbear, but I don't recall - he has two, a 2.0 and a 2.5.  Whatever I have, with a Boss supply I can wiggle it around and the LED doesn't blink at all.
http://smallbear-electronics.mybigcommerce.com/dc-power-jacks-1/

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