Classic ZF trouble..?? 87FC35

[Alan]

It seems I am experiencing the classic ZF trans problem of not going
into gear. It has been kind of slow engaging lately and now it
won't move. **One potential variation is that I noticed my
tachometer does not seem to be registering properly. At idle,
sometimes it was reading around 1500 rpm, and sometimes it's a
little irratic. (The engine is idling normally.) But I don't know
if there is a connection between what my tach registers and the
trans.

So i've read all the posts here I can find about this. I have
located my throttle position sensor and it appears to be in tact and
functioning. I'm now on to the next thing potential problem and
that is a the low voltage problem. I have also found the fix in the
database. The fix says to check the voltage and find the ZF power
supply. I've found what appears to be ZF control module. It is
located underneath the push button gear selectors behind a panel.
It has a large connector on top of it with lots of wires going into
it. I HAVE NOT found what might be the power supply.

So I've got a couple of questions if any one has experience with
this:

1. Where might I look for this power supply. (What does it look
like?)
2. When I find it, I can use a Fluke, so I am anticipating no real
problems in getting to checking voltage..?? Yes?
3. If I do find a problem with the power supply, the fix instructs
me to "retrofit a new power supply". Is this something I can get
from BB or ZF?? Or something I can pick up at Napa??

Thanks in advance,
Alan Johnson
87FC35
Dallas, TX