What is this on my MkIII?

[Ed Mullins]

Recently took the chassis out of my blue stripe MkIII long head to check the 'born on' date and clean it up a bit. Everything seemed normal with the exception of a wooden shim between two of the components (the output transformer and rectifier, maybe?). Can anyone help to explain what it's doing there? Having trouble posting pic. Please follow link below.
Thanks,
Ed

http://img77.imageshack.us/my.php?image=sta701099ec.jpg

 

[Joey707]

The shim is between the choke transformer and the power transformer. It's common on the short heads and combo's. It's to keep the two transformers from touching.

 

[PRS-Ian]

Wouldn't have expected workmanship like that fom Mesa. It looks like the chassis been drilled incorrectly.
Ian

 

[Ed Mullins]

Thanks for the info guys. I agree. It does look like the choke transformer was located incorrectly or the shim was too wide.
The black dot MkIII I owned briefly didn't have this shim. Was this done only on later models?
Ed

 

[Marshall_Fascist]

not on my green stripe :shock:

 

[Ed Mullins]

Should I leave the shim as is or take it out? Or maybe replace the shim with one of an appropriate width so that the choke transformer isn't leaning.
I don’t believe the shim could be doing any harm but you guys certainly know more than I do. The amp sounds incredible and works flawlessly so it's probably best I leave it as is. True??

 

[Joey707]

I would leave it. It might look tacky but it certainly isn't hurting anything.
By the way both of my short head MK III's were originally black dot models and they both have the shim.

 

[Boogiebabies]

Looks like it may be an early MK III with the MK II long chassis. I bet they used up what boxes they had before a redesign for the MK III. I have never seen anything like this, but it is not doing any harm. It may have needed to be so close as not to drill screws through the PCB. Who knows...

 

[Joey707]

Well I just checked my red stripe long head MK III and it has the shim too. On the big heads space is not as much of an issue as on the short heads and combos. Certainly they could have moved the choke further away from the PT if they had wanted to. There must be some good reason why the choke is where it is and that shim is there.

 

[Boogiebabies]

What can I say, it's a Mesa. The MK III has been prototyped on the public since day one and you cannot put one obscure detail past the possibility that that is how they did it.


Welcome to my world...

 

[Ed Mullins]

Thanks guys. All the input has been very helpful. The chassis in the picture is of a blue stripe MkIII long head from 12/88. From the information posted it sounds like the shim is typical on short heads and combos but only appears occasionally on long heads. Seems like anything could be par for course with the evolution of the Mark III series. Good stuff. This board is an awesome resource. I think I'll send a donation.

 

[jay]

my 86 mark III black dot short head has the shim also

 

[scottcrud]

Seems Boogie does strange things sometimes, there is a screw going through my chassis right into the top of the cabinet. The screw is contected to nothing and seems to serve no purpose at all.