Troubleshooting Procedure; Input To Demodulator - HP 3400A Operating And Service Manual

Model 3400A
CHECK
CD
Apply a
the 1 volt range.
of
C413 and C415.
240 m V and 280 m V RMS.
®
Measure ac signal at junction
Demodulator V503 and V504.
5-6 for waveform.
CHECK
CD
Investigate meter (MI). R5. and R6 for opens.
8)
Remove the input to 3400A.
from pin 13 (AG) and insert a +10 mV dc signal
from 738BR through a 499
No. 0757 -0327) to pin 13.
positive side
waveform.
01768-4
Table 5-6.

Troubleshooting Procedure

PROCEDURE
I
volt 400 signal and set the 3400A to
Hz
Measure ac signal at junction
The reading should be between
NOTE
Do
not use an extender board
for measurements on Chopper
Amplifier board A6.
of
C605 and
Refer to Figure
Figure 5-6.
Table 5-6. Troubleshooting Procedure (Cont'd)
PROCEDURE
Unsolder red lead.
resistor (-hp- Part
kll
Measure ac signaL at
of
CGOS. Refer to Figure 5-7 for
PASSE S:
FAiLS:
(Trouble proceeding the
Chopper Amplifier)
PASSE S: Proceed to
FAiLS:
(Trouble in the Chopper
Amplifier).
POSITIVE SIDE OF C605
Full Scale deflection
Sweep
Vertical
DC coupled
use 10:1 probe

Input to Demodulator

PASSES:
FAiLS:
Section V
ACTION
CD
@
to
Proceed
Proceed to
CD <D
to
Proceed 4
5 rns/em
=
0 . 5 V/cm
=
ACTION
®
@
Proceed to
Proceed to
5-9