JVC GX-N7E Service Manual page 35

5. Two-side through-hole PCB
A two-side through-hole PCB is used on this camera.
Patterns and wires are designed extra slim to attain high-
density component mounting. Rough handling may
damage the patterns/wires or other components. When
disassembling, repairing, or adjusting the PC boards,
exercise care to avoid damage.
. When repairing the circuit board modules, please note
that the camera's various circuits are al! contained on
separate independent circuit boards. Each circuit board
can be removed and repaired separately.
{1) Removing circuit board module
Use a solder sucker and completely remove solder
before pulling out circuit board. As shown in
Fig. 6 use a soldering iron with a thin channeled
tip, melt the solder and quickly pull out the circuit
board.
Fig.6 Removing circuit board module
NOTE:
* Take care not to damage or remove solder from
other parts.
* If more than two circuit boards are removed, make
sure that they are replaced in the proper positions.
. Replacing chip components
Use a soldering iron (temperature 260° ~ 300°C, about
17W) with a slim tip and high insulating ability. Those
with-a solder sucker (about 55W) are usually easier
to use,
NOTE: This video camera uses many mini-fiat ICs. To
remove these, melt the solder or cut off the IC
pins. Take care not to scratch or peel off the
BOARD foil pattern.
. Chip components display
Besides the resistors, short jumpers, FET's, ceramic
capacitors, transistors, and other chip components, the
chip tantalum capacitors and chip volume are used on
the camera. None of these chip components are reusable
again once they are used.
NOTE: 1. Avoid rough handling of the VR.
2. Use a thin-tip insulated-type screwdriver to
adjust the CH VR.
@ How to read printings
On certain chip components, printing is applied as fol-
lows:
@Chip metal.glaze resistor (CH MG R)
The diagram shown in Fig. 8-1 @) is applied to
some of these resistors.
Reading method (Example)
123=12x10) Unit: (J
@Short jumper (0 [2] of CH MG R)
No diagram is applied to short jumpers. A "0"
display is applied to Type @) shown in Fig.
8-1.
Tolerance Multiplier — Constant
Fig. 8-1 Example of CH MG R/CH C Cap. codes
@ Chip ceramic capacitor (CH C Cap.)
+ The diagram shown in Fig. 8-1 ©) is applied to
some of the CH C Caps. On some others, there
is no diagram that is of any use to users.
Reading method (Example)
1Z3K=12x 103 Unit: [PF], Tolerance: K (+ 10%)
+ As shown in Fig. 8-2 some chip ceramic capaci-
tors are represented by two digits. Table 8-1
shows how those figures should be read.
A
'
1'o x 1 = 10000pF = 0.0tuF
Fig. 8-2 Example of CH C Cap.
(No. 5550) 5E
r a e
i | Alphabet
Alphabet | A] B} C/O] €E 1 F
Constant 1.0/1.1 15/16
Alphabet | L | M|N R
Constant |} 2.7] 3.0 3.9 14.3
Alphabet | W | X | ¥
Constant | 6.8
Constant it | 6. 0
ate Numeral 2|3.,/4|5{6|7|8|9
Muitiptier | 10°|10"| 107| 10°|104| 10° hozj10!
Table 8-1 CHC Cap. capacity value
@ Chip Variable Resistor (CH VR)
A two-digit code is printed on:some CH VRs.
They indicate a reading method, as shown in
Table 8-2.
1 Three-digit codes are also used. These codes are
read in the same way as those for CH MG R.
® Chip Tantalum Capacitor (CH Tan. Cap.)
The diagram shown in Fig. 8-3 is applied to
some of the CH Tan. Caps.
Reading method (Example)
The type shown in Fig. 8-3 is 10 nF, 16 WV
chip tantalum capacitor.
Capacity : {uF |
Polarity: + side
Withstand voltage
Fit. 8-3 Example of CH Tan. C Cap. codes
© Chip Transistor
The labels shown in Table 8-3 are applied to the chip
transistor.
Part No. Display method
28C2778(B, C, D)
serees Pafts ranking : B
28C2404(0}
28D601(0, R)
2SD601A(Q, R}
2SD1030(R)
288709(P-R)
2$8792(0-T) [e3]
288970(0-S)
28A1022(C)
eee
Table 8-3 Chip transistor labels
@ Chip FET
The following printing is applied to the Chip FET.
2SK198 (Q)
Coding method
parts ranking: Q
denotes
2SK 198
Table 8-4 Chip FET codes
® Chip Diode
The following labels are applied to the Chip Diode.
Part No. Coding method
MA151WA BAN]
denotes
MA151
MAISIK (m.H]
MA1SIWK
MAI5SIA
MA157
MA3047-L 4.7L
Table 8-5 The display of chip diode
Code
Table 8-2 CH VR resistance value display method in two-digit
6E (No. 5550}