HV shutdown
 

Mitac L1450PD monitor

i get HV for about half a second then it shuts down.
heater glows orange 6v at crt neck.
G1 and G2 drop to 0v after shutdown.
HOT ok.
removed HOT and placed a 240v 40w globe across collector and gnd.
lamp lights up.
i measured B+ at one of the caps on the secondary side of the chopper
and get 152v.
is this a good place for B+ and is this voltage too high?

The symptom you are describing is usually attributed to a bad flyback
in your model of monitor. The drive transistor should be changed along
with it when this is the case.


Jerry G.
========



BigTom wrote:
Mitac L1450PD monitor

i get HV for about half a second then it shuts down.
heater glows orange 6v at crt neck.
G1 and G2 drop to 0v after shutdown.
HOT ok.
removed HOT and placed a 240v 40w globe across collector and gnd.
lamp lights up.
i measured B+ at one of the caps on the secondary side of the chopper
and get 152v.
is this a good place for B+ and is this voltage too high?

i replaced the flyback and drive transistor with one out of another
monitor(same part No).
still the same. could be bad as well.
measured the B+ at flyback and found 152v.
it looks like this voltage is from the power supply.
ive read somewhere that B+ should be around 120-130v.
is this right?

Jerry G. wrote:
The symptom you are describing is usually attributed to a bad flyback
in your model of monitor. The drive transistor should be changed along
with it when this is the case.


Jerry G.
========



BigTom wrote:

Mitac L1450PD monitor

i get HV for about half a second then it shuts down.
heater glows orange 6v at crt neck.
G1 and G2 drop to 0v after shutdown.
HOT ok.
removed HOT and placed a 240v 40w globe across collector and gnd.
lamp lights up.
i measured B+ at one of the caps on the secondary side of the chopper
and get 152v.
is this a good place for B+ and is this voltage too high?