HP 5501A Operating And Service Manual page 222

Table 6-7. HP-It? Interface Electronics System Troubleshooting (Cont'd)
ACTION
If optics are mis-
aligned and beams
do not overlap,
refer to Section II
for alignment pro-
cedure.
Refer to 10780A
manual for
adjustment pro-
cedure.
Rotate interfero-
meter 90 degrees
and look for in-
crease in test
point voltage.
Troubleshoot
appropriate
component
I
b) Intermittent measurement signal on one or more measurement axes may indicate:
CAUSE
1.
Misalignment of
optical compo-
nents.
2. Misadjustment
of 10780A
receiver gain
3. Low power in
frequency used
for measurement
4. 10780A Mal-
function, cable
intermittent,
or 10760A mal-
function.
'Use laser power meter filtered for 6328 Angstroms (e.g. United Detector
CHECK
Reduce beam size by
rotating to small
aperature on laser
head. Place align-
ment target on
receiver lens. Move
optics along entire
measurement path
and verify both re-
turn beams overlap
on the target along
the entire length
of movement.
Monitor 10780A test
point on back of
receiver, voltage
should lie in range
0.5-1.0 Vdc. If
voltage >I.lV,
receiver could be
saturated. If volt-
age <0.2V, gain may
be too low.
Use power meter, if
available, and
polarizer and check
relative power of
horizontal and
vertical polari-
zation.*
Look at output
signal from 10780
and input of 10760
Technology
W X
meter [w/filter) ).