Sony CPD-G400 Training Manual page 33

The procedure is as follows:
1. Position the main board to access the power supply. You will not
need the picture tube nor degaussing coil. You will need the +5 volt
loads on the D board and the CRT's A board.
2. Disable the HV by shorting Q902's Source and Gate leads. Q902 is
on the large heat sink on the main D board near the relays. The
Source and Gate are the outer leads on this TO-220 case FET.
Q902
G
Surge Relay
RY602
3. Disable SCR D616 by shorting diode D617 nearby. D617 is con-
nected to the SCR's gate and cathode.
G
4. Keep the Yoke connected to the D board (CN1 to CN501) so the unit
will not go into ABL shutdown.
5. Keep the CRT's A board connected at CN306, CN309 and CN311 for
CPU communications and power.
Q901
S
Degauss Relay
RY601
D617
K
D616
SCR
A
27
6. Apply external +5Vdc in series with a diode to IC605/pin 1. This turns
ON 5V regulator IC605 and 12V regulator IC604. You may want to
place a diode in series with the external +5V power supply to prevent
damaging your test equipment. Use the shield as a cold ground. Al-
ternate procedure: If you do not want to use an external power supply,
the monitor will normally enter the Active Off Mode after one minute.
At that time, press a front panel mode button to return the Monitor to
the Normal Power Mode.
7. Press the power ON button and the monitor's power supply will come
up in the Normal mode and remain in that mode. After one minute
without sync input, the CPU will turn ON the front panel Orange indi-
cator, but the monitor voltages are active except for the final HV, Heater
voltages and FBT voltages.