[Elecraft] Semi-OT [K3]: TPL 2 meter amplifier question

[Lewis Phelps]

I recently picked up a TPL Tempo amplifier from a local SK estate sale. The amp is specified as a Class C (FM only) amp; 10 watts in, 110 out.  The power amplifier consists of three B40-12 transistors in parallel, with a fourth apparently serving as a pre-amp. There are a number of old TPL amp manuals available online, but none for this particular model, so I don't have a schematic.

The seller told me the amp had been modified by the prior owner to bias the power transistors so that it now functions as a Class A amp with 70 watts out. I've opened the case and there appear to be some circuit mods, but I can't tell whether they do what they are purported to do. 

I have found a one-page spec sheet for the B40-12 transistor, which characterizes it as designed for use in Class C amps for mobile FM operation.  

So here's the question:  is anyone on the list sufficiently familiar with the TPL Tempo to advise (a) whether it can indeed be modified to serve as a class A amp, and (b) what the mods would look like.

thanks, and 73

Lew N6LEW

Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10 
Yaesu FT-7800 
Lew at N6LEW.US
www.ntlew.us