LSS Chassis Bolt

[Dr. Tweedbucket]

YOu guys are all NuTZ :lol: :lol:

 

[1028paul]

The screw in question.. just to clarrify...

on second pic, you can see the top of the screw has a grounding plate to make good contact with the shielding above.

 

[dougbilski]

How hard was it to remove the chassis? I'm thinking of trying to repair my "screw" up (pun intended) by replacing the screw and putting some wood putty into the underside of the cabinet where I undoubtedly chewed the heck out of it overtightening that screw!

What does that screw push against? Right into the wood of the cabinet or is there some kind of plate or something there?

 

[1028paul]

dougbilski,

I just found that pic on the web when researching what the screw does, not had my chassis out. so Im not qualified to help, other than presume the top of the screw tightens against a foil sheet on underside of the cab top.

Paul.

 

[stonevibe]

I've pulled my chassis out before to check when I thought my reverb was fubar.

It is not to hard just take your time and mind where you take your screws from....

 

[ellem52]

My Lonestar does have a "rattle" especially when I play clean. Is this a screw I should look into tightening to reduce the rattle?

(OK, look when I play on the Drive channel everything in the house shakes so much I have no idea what the amp is doing.)

 

[Rusty]

Thanks for clearing up the mystery on this screw for me.

Here's a shot of one sticking out of my Rocket 44:

 

[Ken j]

... the top of the screw tightens against a foil sheet on underside of the cab top.

Paul.

That is correct. The screw should just be snug. Do not over tighten. Note you need to loosen this screw before removing the chassis, from the cab.

 

[SgtThump]

Well I'll be damned... I just got an Electra Dyne combo and when I had the amp apart checking stuff out, I saw that long screw sticking out there. It looks really out of place. I couldn't figure out what the heck that's for and was thinking about calling Mesa just to ask. Then I saw this thread. LOL! Thanks for the info!

 

[Addictedtokaos]

Does anyone have any info on this screw? My amp is missing it. I left a mesa with Mesa Tech support with no reply.

It looks like a #8 or #6 (32) coarse 3" screw. Can anyone confirm this.

Also, how much damage to the foil shielding would have to be done to warrant replacing it? there looks like there may be a few small tears (1/8") where someone over tightened the screw.

Ive read some people use screen, aluminum ducting sheets, or plain BBQ foil. Anyone have any experience with any of these materials?

 

[Vogelsong]

I needed a laugh today, the funny thing is I just found this screw myself today and was wondering all the same stuff.

You guys are too much.

 

[rfrakes]

I replaced mine with a cryogenically treated screw! Sounds much better now.

 

[rfrakes]

I would think you would have to back this screw off a bit when sliding the chassis out or you might rip the foil shield.

Is this correct thinking?

Thanks, Ron

 

[MrMarkIII]

I would think you would have to back this screw off a bit when sliding the chassis out or you might rip the foil shield.

Is this correct thinking?

Thanks, Ron

Yes. Remember to drain the caps, because sticking your hands inside the chassis can kill you.

 

[tele twister]

Would it be possible for a loose shard of foil to fall down on the circuit board or tube socket and short something? I'm thinking about screwing a small repair plate there, 2" X 2" made of aluminum sheet metal.

My RoV2 had signs of an arcing on a tube socket when I got it,(used). Now I'm wondering if it was a shard of foil. My foil is all chewed up there.

 

[Nicklotsaguitars]

What that screw is doing is completing a Faraday cage. Contacting the foil of the cabinet it's sending the small charge running through the chassis, to the foil. This stops a lot of EM/RF noise.
As for repairing the foil, a bit of copper tape will work fine.

Recently put my Mark V in a headshell that didn't have the foil. It was a bit more noisy and the footswitch clicked/popped.
Put it back in the combo housing and all is fine.

 

[grritz]

I think it says something very positive about Mesa that they would even think about a "tension screw" to help prevent buzzing of the chassis against the cabinet.
I mean...what other amp maker does this?
I'm a Mesa Boogie newbie, but this is just another reason I'm soooo glad bought a Mesa amp!

Thanks, Mesa!

 

[bandit2013]

The RA100 combo has the same thing going on with the tension screw. Never seen one on the Roadster but there is a square hole in the chassis of the Mark V that appears to have been something deleted.

I guess no screw would make things airy, that is great as I play 'air' guitar most of the time anyway. (I know... to late..... )

 

[Frankolino]

Well, the screw is not therefore to make contact with the foil. Because there are 4 screws on the underside of the chassis to make contact to the foil and make a faraday shield to protect against RFI.
You can see that very well in the picture of a Nomad 55W I found in the internet.
( Bare screws on the left and right )