Mark III Triode vs. Pentode Wiring

[path09en]

Folks,

How can I tell visually if a Mark III is wired in Pentode vs. Triode. I'm not sure if my Green Stripe Short Head is Green and I need to identify it asap! The Serial number is 25311. Dated July 1989.

Thanks!

 

[Boogiebabies]

Triode - Pins 3 and 4 on the outer tubes sockets will be connected by the screen grid resistor.

Pentode - Pins 3 and 4 are not connected by the screen grid resistor.

 

[Tom P]

Is there a simple (DIY) way to mod a blue stripe to pentode?