Servicing Etched Circuit Boards; Factory Selected Components - HP 3400A Operating And Service Manual

Section V
f. Replace the top cover and two phillips head
screws in photochopper block.
g.
Recormect the cable to pins 2, 3, 4 and 5.
The larger black lead in the cable connects
to pin 2. other leads identifications are as
follows:
White lead to pin 3
Green and red lead to pin 4
Thin black lead to pin 5.
h. Replace chopper amplifier board.
5 - 4 3 .
SERVICING ETCHED C I RC U IT BOARDS.
5-44. The -hp- Model 3400A
boards. Use caution when removing them to avoid
damaging mounted components.
-hp- Part No. are silk screened on the interior of the
circuit board to identify it.
parts replacement and -hp- part number information.
5-45. The etched circuit boards are a plated-through
type. The electrical connection between sides
board is made by a layer of metal plated through the
component holes. When working on these boards.
observe the following general rules:
a. Use a low-heat (25 to 50 watts) small-tip
soldering iron and a small diameter rosin
core solder.
DESIGNATOR
C205
Adjust low frequency (10 Hz) response.
C302 Adjust high frequency (10 MHz) of Second Attenuator
on
O.
C304
Adjust high frequency (3 MHz to 10 MHz) of Second
Attenuator on
C305 Adjust high frequency (10 MHz)
on
O.
C427
See NOTE on schematic.
Adjust the raoge
R3
Adjust the range of R7 (1/10 SCALE ADJ).
R8
R419 Adjust voltage at collector
I. 5 to 2. 5 Vdc).
5-16
has
five etched circuit
The assembly and
vn
Refer to Section for
of
the
Table 5-7.

Factory Selected Components

FUNCTION
001 V and 1 V ranges.
3 and 300 V ranges.
O. V
01 and 10 ranges.
V V
of
R4 (CAL).
of
Q406 (no Signal input,
b. Circui t com]Xlnents can be removed by plac­
ing the soldering iron on the component lead
on either side of the board and pulling upon
If
lead. a component is obviously damaged,
clip leads as close to component as possible
and then remove. Excess heat can cause the
circuit and board to separate or cause dam­
age to the component.
c. Component lead hole soould be cleaned be­
fore inserting new lead.
d.
To replace components. shape new leads and
insert them in holes. Reheat with iron and
add solder as required to insure a good elec­
trical connection.
Clean excess flux from the connection and
e.
adjoining area.
WATER. COMMERCIAL CLEANERS.
OR DETERGENTS WILL CAUSE PER­
MANENT DAMAGETO PHOTOCHOPPER
ASSEMBLY A5.
To avoid surface contamination of the print­
f.
ed circuit. clean with weak solution of warm
water and mild detergent after repair. Rinse
thoroughly with clean water. When complet­
ely dry. spray lightly with Krylon (#1302 or
equivalent).
LOW
-
5 pF
--
of
Second Attenuator
-
-
820
---
270
Model 3400A
VALUE
NORMAL
HIGH
--
100 /iF - - -
(selected)
12 pF 15 pF
24 pF
- 39 pF
-- 5 pF
12 pF
- - -
- 200 /iF -
(selected)
Il
Il
1200
2.16 kll
Il
- -
390 -
(selected)
300 --
-
01768-3