HP 203A - Page 28

С
Моде! 203А
Section V
Table 5-6
Table 5-6. Troubleshooting Summary
Symptoms
1. No output on any channel
2. Output on one channel only
(sine and square)
3. No square wave output
4, No output on variable channel
(sine and square)
6.
Distortion
on
REF
Sine
OUT-
PUT
varies
as
PHASE
LAG
dial
is
rotated
Possible Cause
Check:
VFO
output
at
XA10
pins
4
and
6
(X1K
range),
If no output, check 555 kc output XA1 pins 5 and 6.
If no output at (2), check 4. 995 Mc output XA1 pin 1.
Check
power
supply
voltages
and
continuity
between
circuit
ground
and chassis. 1f output is at (2) but not at (1), check:
а. AIOLI, L2 for open.
р. А10С11, C15 for short.
c. А10С5, C8 for open,
If output is at (3) but not at (2), check:
a. Open windings in AIT1, T2 or L2.
b. Low beta of A1Q3 ог 04,
If
no
output
at
(3),
check:
(Dand
crystal
Y1,
transistor
А101
Check: output at pins 2 and 4 of XA6 or ХАТ,
If no output, check pins 12 or 4 of XA3.
If output is at (2) but not e check:
а. A4 or А5 at pin 6 then pin 1.
b. L1, L2 or L3 might have case grounded.
If output is at (3) but not at pin 4 of ХАЗ, check:
а. А399, T2, T4 for open.
b. Misadjustment of A3R31 or R34,
If output is at (8) but not at pin 12 of XA3, check:
а. AS3Q4, Ті ог ТЗ for open.
р, Misadjustment of A3R17 or R20.
(1) Check: Input pin 1 of ХА8 or ХА9,
(2) И no signal, check output pin 2 of XA6 ог ХА".
(3) If signal is at (1) check output pin 6 of XA8 ог ХА9,
(4) If signal is at (1) but not (3), check:
a. A8Q5, Q4 or CRI for open.
- b. A9Q5, Q4 or СКІ for open.
(1) Check: output of RF Amplifier pin 7 of ХА2,
(2) If no signal at а), check input pin 4 of ХА2,
(3) И no signal at (2), check pins 3 and 14 of ХА2,
(4) If output is at (3) but not at (2), check components in А25.
6)
If
no
output
at
G)
no
output
at
(2),
check
components
listed
under
second
symptom.
@ Defective A2Q1 or A2Q2.
01760-3