Hi Duaine,  For my piano, and I expect many others, access to the
governor in an Ampico A drawer is a bear.  It is crammed inside the
very back of the drawer on the right-hand side.

I have managed to access mine by opening the drawer and lowering the
right side onto a supporting structure to gain access.  In order to do
this safely I pile supporting material (books, sturdy boxes, and what
have you) under the right side of the drawer to take its weight when
dropped a few inches).  For safety's sake, I block the left side as well.

Then I carefully unscrew the roller mechanism on the right side enough
to free the rollers so the drawer can drop down onto the support you
have placed under it.  This makes the governor considerably more
accessible.

The most likely problem causing uneven Tempo will be a warped celluloid
"keyhole" valve facing under the leather-faced Tempo slide.  The governor
itself couldn't be more straightforward -- no knife valves -- so don't
take it apart any more than is necessary to observe the Tempo valve
function.

I learned this technique many years ago from Dean Randall, now no
longer with us, and his impression seemed to be that he thought
everyone knew it.  Such is life.

Jim Heyworth,
Sechelt, British Columbia, Canada