I am working on a Knabe Ampico "A" that was rebuilt 20 or so years ago.
It hasn't played up to par in a while, but now the air motor has slowed
substantially.

I went to see what the static pressure at the pump was and disconnected
a supply tube on the pump to put my manometer on the nipple, but I could
not get in there to do so. So I need to make a "downspout" to get
a manometer on the supply.

I put my hand over the nipple at the pump, and there was suction, but I
felt it was lackluster and weak. I somehow remember the static pressure
at the Ampico pump is supposed to be around 20". (I seem to have a lot
more suction feel from a bench pump on my bench at home, which is a Lee
retrofit pump for upright players.)

When I put pressure on the spill valve to close it, things start coming
up a little nicer, though still not up to par. There appears to be
a small and constant weep from the valve.

Several questions:

1. Can someone point to a possible problem they see from my description
above?

2. What is the static pressure from a properly rebuilt Ampico pump?

3. Has anyone seen a situation where the RPM of the motor should be
checked? I believe the RPM should be 1400 at the motor shaft. Should
I invest in a contact tachometer to check the speed of the motor?
Visually it looks like the pump is "at speed".

I know that -- at 20 years old -- the previous rebuilding job, which
appears to be a decent job, is getting old and anything can happen.
But I was wondering if there is anything I should look at first.

I know players, and I have a little working knowledge of reproducers,
but not enough that I can just walk in and say "that's it". I don't
want to waste time and money constantly doing trial and error, if there
is a more efficient way of doing things, but if it this is a diagnostic
check and test, then that's what it will have to be. I do have most of
the manuals as well.

Thank you all!

Keith Gramlich
East Meadow, New York
tel.: 1-917-757-4207
wurli1@live.com.geentroep [delete ".geentroep" to reply]