What does this red wire do?

[boogietone]

Is this red wire supposed to be here? It looks like it was added to the amp at some point. And why do you think it would be there if it was added to the amp? It goes from the board to the amp cabinet where it is attached by a screw. This is on a MKIV.
Thanks!

http://s145.photobucket.com/albums/r216/np0206/?action=view&current=redwire1.jpg

http://s145.photobucket.com/albums/r216/np0206/?action=view&current=redwire2.jpg

http://s145.photobucket.com/albums/r216/np0206/?action=view&current=redwire3.jpg

 

[mrd]

Maybe it's a ground? Not sure... looks kinda strange. I'd wait for one of the more technical guys to pop in.

Might help to take some more in-focus pictures though, ones that show specifically what part of the board the wire is connected to.

 

[Boogiebabies]

Mesa used to use a strip of braided wire screwed from the foil shield in the top of the cabinet to one of the SUS-4 mounts. This looks like an attempt to do the same. The later MK IV's used raised brass contacts that contacted the foil shield on both sides of the chassis. They look like 5 thin fingers.

 

[Buddy]

Ah yes , Nothing like WHY WON'T THIS COME OUT !!!!!!!!


.
Back in the old day's

With an amp I had to figure out the hard way ...


When I had the old tube computer ........

 

[boogietone]

So I definitely need that wire hooked up right? The new head box I'm putting the chassis in doesn't seem to have any provision for the wire hook up that the combo box had. Would clearing off some paint and installing a screw work? Or maybe go right to the sus screw?

 

[fatoni]

the red wire is what you cut to diffuse the bomb...or was it the blue wire? :wink:

 

[Buddy]

I busted the braid off the first time I pulled the chassis . Couldn't wait to look inside/snoop around .
Any way , I never noticed a difference with or without .
but I replaced it with new braid and soldered ring terminals .

 

[boogietone]

I busted the braid off the first time I pulled the chassis . Couldn't wait to look inside/snoop around .
Any way , I never noticed a difference with or without .
but I replaced it with new braid and soldered ring terminals .

Where exactly is the wire installed in the cabinet? I see the provision for it in my combo (though I don't know if it is original or if someone added it) but not in the headshell I have for it. I'm changing my MKIV from a combo to a head. Guess I could just run it without for a while and see what happens. Thanks for all the replies!

 

[Buddy]

There should be some foil glued to the(inside)top of the cabinet .
Screw it to that and the chassis .
Its noise shielding .
On mine I have an extra hole next to the aux power plug ; I used that .

 

[boogietone]

Thanks. I'll look again.

 

[Boogiebabies]

None of my head shells have it. It was only used on SUS mounts. I think the most plausible reason is that with the SUS mounting, the foil shield did not touch the chassis except through the braid connected to the SUS mount casing and the mounting screw was the actual ground connection I think the combo's used this for extra RF shielding since they hung down a bit allowing for some possible noise pickup. For the heads, the chassis snugs right up to the foil.