IEC 30 Series - Page 47

SECTION 5
Table 5-1. Troubleshooting Guide (Continued)
Symptom/Step
Possible Cause
Remarks
b.
Base line of triangle
and sine offset from
zero.
Misadjustment of R228.
c.
No dynamic
triggering.
Same as 9a.
d.
No
manual triggering.
Same as 9b.
e.
Baseline oscillations.
Start/Stop trouble.
See step 23.
11.
BURST MODE
FAULTS.
a.
No
burst output.
1.
Open circuit from TP27 to R277 when in burst
mode.
2.
Same as 9a.
b.
Continuous output
only.
Same as 9a.
12.
SWEEP FAULTS
a.
Waveform
nonlinearity.
1.
Q61. Q64. Q65 leaky.
2.
CR73. CR74. CR75
leaky.
3.
C121-C125 leaky.
b.
Vernier <100:1
sweep time range.
IC15 faulty.
c.
No Sweep
Same as 19.
13.
TRIGGERED SWEEP
FAULTS
a.
No sweep.
Same as 19.
b.
Double
sweep.
Excessive rate on TRIG/SYNC input.
c.
Interrupted sweep.
1.
Q63 failure.
2.
Logic Failure.
See step 22.
14.
OUTPUT AMP
FAULTS
a.
Positive Output
« 11 v open circuit)
at all times.
1.
Q33. Q17. CR31 or CR32 open.
2.
Negative supply not operating.
3.
VR7
shorted.
4.
IC9
faulty.
5-7