HP -7035B Technical Manual page 54

PROBLEM
8. (cont)
9. X-axis motor stalls when
end of scale stops are
hit. (Prolonged operation
in this condition may
damage motor or ampli-
fier - motor must not
stall. )
10. Recorder response ex-
tremely slow - operating
on 1 mv/inch (0.4 mv/cm)
range.
11. Zero position not repeat-
able during recorder
"set-up" - using 1 mv/
inch range (0.4 mv/cm).
12. Pen carriage wobbles
causing poor writing.
13. Y-axis moves in jerks,
seems to occasionally
bind or stick.
14. X-axis moves in jerks,
seems to occasionally
bind or stick.
7-4
TABLE 7-1. 7035B TROUBLESHOOTING INDEX (Continued)
POSSIBLE CAUSE
c. Excessive X-axis gear backlash.
X drive belt too tight. Measure
per paragraph 5-78.
Input signal source impedance too
high (paragraph 5-92).
No source impedance connected to
input.
Pen carriage wheels too hose.
a. Drive string too loose. Measure
per paragraph 5-66.
b. Pen carriage wheels set too tight.
c. Insufficient backlash in gears (too
tight).
d. Motor brushes excessively worn.
e. Motor brush stuck, held off
commutator.
f. Bearing in drive system faulty.
g. Excessive mechanical friction.
Unit needs general cleaning and
lubrication.
a. X-axis slider rod bearings too
tight.
b. X-gear backlash insufficient (too
tight).
c. Motor brushes excessively worn.
d. Motor brush stuck and therefore
held off commutator.
e. Bearing in drive train faulty.
f. Excessive friction.
CURE
c. Adjust backlash (paragraph 5-83).
Adjust (loosen) drive belt
(paragraph 5-79).
Use lower source impedance.
Place resistance across
input terminals (+ to -).
R to be 20K or less.
Adjust pen carriage wheels
per paragraph 5-71.
a. Tighten drive string (see
paragraph 5-67).
b. Adjust pen carriage per
paragraph 5-71.
c. Adjust backlash (paragraph 5-69).
d. Replace brushes (see paragraph 5-38).
e. Free-up brush (see paragraph 5-40).
f. Replace bearing.
g. Clean and lubricate per
paragraphs 5-9, 5-12.
a. Adjust slider rod bearings
(paragraph 5-85).
b. Adjust backlash (paragraph 5-83).
c. Replace brushes (paragraph 5-38).
d. See paragraph 5-40.
e. Replace bearing (paragraph 5-87).
f. Clean and lubricate per
paragraphs 5-9 and 5-12.