On Tue, 10 Jul 2012 15:35:51 -0000, "keithostertag"
<keitho@...> wrote:
TP1801 measures 5.69V (SM says should be 5.7V)
TP1805 measures 1.74V (SM says should be 1.8V)
So maybe, as David says, that sugggest the (main) problem is not earlier in the z-axis signal chain?
That is what your readings suggest to me. The problem appears to be
in the z-axis amplifier itself and not earlier.
Unfortunately the z-axis amplifier is pretty complicated. Fortunately
it should have relatively fast repetitive waveforms so it will be
easier to see on your non-storage oscilloscope.
TP1827 right in the middle of the z-axis amplifier divides it into two
sections and that test point is the output of a low impedance emitter
follower. I would check TP1801, TP1805, and TP1827 with an
oscilloscope and see if they match what is shown on the schematic.
After that I might start randomly looking for shorted or open
transistors in the second half of the circuit starting with Q1876 and
Q1854.
David Hess