CORRECTIVE ACTION
PROBABLE CAUSE
MALFUNCTION
16.1.1. No trace
Fuses F1, F2
Check for switches
on CRT charger
transistor Q50, IC U21.
battery at drain of
(line) light and
Q50. Replace faulty
power light not
component. If fuse
on.
is replaced and fuse
opens when machine
powered up, check for
short circuit in scope power
supply/charger.
16.1.2. No trace
1. IC U20, Q20, Q21,
Check for 12. If
on CRT charger
T2 and associated
not present. find and
(line) light and
power supply
replace faulty
power light are
components.
component.
on or, trace
fading on CRT as 2. CR21.
Check for 500v at cathode of
battery voltage
CR21. Replace CR21 if open
decreases.
or shorted.
3. CR20.
Check for 65v at anode of CR25.
Replace CR20 if open or
shorted.
4. CR25, CR26.
Check for 48v at anode of CR25.
If voltage is greater than 50v or
less than 46v, replace faulty
5. Hv multiplier.
If 500v is present,
check for 5.1kv at
anode of CRT. Replace Hv
multiplier.
6. Dirty pins at CRT
Visual inspection.
connector.
Clean pins on CRT.
Figure 2-3. Monitor troubleshooting guide (continued).
MD0362
2-41