Service manual

19SV111
TROUBLE SHOOTING TABLE (Continued)
Malfunctions Traceable to Game Deck
* Prior to replacing parts:
Check the following items before referring to the tables on the following pages and
repairing the Game Unit.
1. Check the contact condition of card connector 72P.
2. Check the soldering of all parts.
3. Visually inspect for short circuits.
4. Check that all parts are mounted correctly.
5. Check for ICs that heat up abnormally while power is on (other than ICS PPU).
6. Check for splitting or cracks in the resistor arrays, ceramic capacitors, ceramic osci II ators, etc.
Symptom Repair Procedure
Display in One Color
Sound normal.
Sound normal.
1. Check for faulty soldering.
ICS PPU faulty.
1 . Check for faulty parts or faulty soldering near the
crystal oscillators (labeled X1 and X2 on the Game
Unit).
2. Measure the osci!! ati on frequency and input
voltage at IC6 CPU pin (29) and res PPU pin (18).
The oscillation frequency should be 21.5 MHz.
(see diagram below}.
3. Measure the oscir ration frequency and input
voltage at rC10 CIC pin (6) . The oscillation
frequency should be 4 M Hz.
(see diagram below).
4. Check soldering for IC6 CPU, IC1 5-RAM and IC3.
Faulty rc6 CPU, ret 5-RAM, res PPU, rc3 or IC9.
Location of Fault
(in order of probability)
(1) ICS PPU
(1)
IC6CPU
(2)
IC1 5-RAM
(3)
ICS PPU
{4)
X1, X2
(5)
1(3
(6)
1(7, 1(8
(7)
MP1, MP2
(8)
IC9
(9) Card connector
"DE" 72P
( 1 0) Faulty soldering or a
break
in the
conductor pattern.
4MHz
2 t .5 MHz (NTSC)
230 ns
12