[Patrick Turner]

Does anyone have a *readable* electronic copy of the schematic for
HP-333A distortion measurer?

The one I have which was given to me had lots of faulty plug on leads
to pcb boards which are double sided, with discrete SS comnonents. I
fixed all the loose leads but the volt meter starts to measure wrong
voltages after turn on. It begins measuring nearly OK then the Vrms
reading drifts upwards to about twice the correct value. I searched
with Google for 2 hours for a free copy, and of course some sites said
they had free copies, but there always was a hefty fee to pay, so I
have nothing. An Army user manual has some difficult to follow user
instructions but no service info.

The HP is not as simple and easy to use to use or as revealing as the
THD meter I designed and built 14 years ago, but my meter only does 1
frequency, 1,000 Hz, wheras the HP has a huge range of frequencies,
and a wien bridge gadget to null out the fundemental of any frequency
being examined . This appears to be working but the HP meter is
faulty, and probably there is some part on the pcb metering amp which
isn't right. I could not see how to set the meter to read a known
applied voltage.

Patrick Turner.