Help please with my Mark III!

[fxvinyl]

Hi - I have a MarkIII combo and am trying to sort out what year it's from. It has the blue stripe and appears to have "4/88" written by and on the chassis with some initials I cannot decipher next to the date. Has (the original?) Mesa B branded tubes. Any guidance much appreciated. TIA.

 

[rarebitusa]

Blue Stripe (1988)​

The fourth revision was the "Blue Stripe" Mark III which featured a blue marker stripe above the power cord. The lead channel was voiced so brightly, it is considered to be the most aggressive Mark Series Boogie ever introduced. The presence cap and voltage rating of some of the orange drops in the power section were also altered to mirror that of the IIC+

 

[fxvinyl]

Blue Stripe (1988)​

The fourth revision was the "Blue Stripe" Mark III which featured a blue marker stripe above the power cord. The lead channel was voiced so brightly, it is considered to be the most aggressive Mark Series Boogie ever introduced. The presence cap and voltage rating of some of the orange drops in the power section were also altered to mirror that of the IIC+

Thanks v much. And the hand written date on the chassis is typical?

 

[rarebitusa]

April 1988 is the date code, that matched with a Blue Stripe.

Here is the operating manual that should be helpful.

Mark III manual

BTW, take a look at page 11 and the arrangement of tubes for Simulclass. It appears in the pic you sent that the tubes are incorrectly placed WRT to operating el34/6l6 in SimulClass mode.

 

[Gearhunter]

The initials by the date code are MB, for The Man, Mike Bendinelli.
As @rarebitusa said, your power tubes are installed with the pairs side by side, when the EL-34s should be the outside and the 6l6s in the middle. So the power tubes will go:
EL34 6L6 6L6 EL34.
Congrats on the amp