J
Jason D.
Guest
I'm stuck with this particular monitor and frustrated for not famillar
with sony's design especially power supply and how it is done.
The power supply seems too low on some outputs except I'm getting 13V
for the 5V standby regulator so microntroller is getting good 5V
standby.
Microcontroller is not outputting error LED flashes. Scoped the IIC
(I2C) bus and see repeating activity, microcontroller's 24mhz crystral
is running. Other two ICs has no power either because microcontroller
isn't revving up the power supply or turns on regulator switch.
13V is on 180V, almost nothing on some of outputs and there is no sign
of short because I removed most of loads except for 180V feedback
circuit is kept intact to keep SMPS in regulation and 5V standby.
Also I'm curious why this monitor has location D319, a small OT359
(currently BT149G is available, OT359 is discontinued) power thyristor
ACROSS two positive rails of two different voltages, 180V and
unregulated voltage for the standby regulator?
UPDATE: answered myself when I found tidbit by accident when googling
for BT149G, in their philip datasheet for 200V smps, this is for burst
standby mode switch. Gee! Sony took some of that idea from philips.
Found the schematic for it except don't have the troubleshooting
section, need that one or your tips on this one.
Thanks & Cheers,
Wizard
with sony's design especially power supply and how it is done.
The power supply seems too low on some outputs except I'm getting 13V
for the 5V standby regulator so microntroller is getting good 5V
standby.
Microcontroller is not outputting error LED flashes. Scoped the IIC
(I2C) bus and see repeating activity, microcontroller's 24mhz crystral
is running. Other two ICs has no power either because microcontroller
isn't revving up the power supply or turns on regulator switch.
13V is on 180V, almost nothing on some of outputs and there is no sign
of short because I removed most of loads except for 180V feedback
circuit is kept intact to keep SMPS in regulation and 5V standby.
Also I'm curious why this monitor has location D319, a small OT359
(currently BT149G is available, OT359 is discontinued) power thyristor
ACROSS two positive rails of two different voltages, 180V and
unregulated voltage for the standby regulator?
UPDATE: answered myself when I found tidbit by accident when googling
for BT149G, in their philip datasheet for 200V smps, this is for burst
standby mode switch. Gee! Sony took some of that idea from philips.
Found the schematic for it except don't have the troubleshooting
section, need that one or your tips on this one.
Thanks & Cheers,
Wizard