Samsung LA32B350F no backlight

[mrobo]

Re: Samsung LA32B350F no backlight

I cant measure the voltage on pin 4 and pin 5 UM801S = my multimeter starts beeping I have it on 750ACV or 1000DCV

[mrobo]

Re: Samsung LA32B350F no backlight

if your board has PFC IC (FAN 7530) i think it is i would check your getting all the correct volatges too it as for some reason the pfc is staying low

how to measure it is on the other side of board
should measure with disconnected lamps?

[budm]

Re: Samsung LA32B350F no backlight

I cant measure the voltage on pin 4 and pin 5 UM801S = my multimeter starts beeping I have it on 750ACV or 1000DCV

Why do you want to measure the Voltages on UM801S? That is standby power supply section and it is working.

[vinceroger69]

Re: Samsung LA32B350F no backlight

probably my fault budm was trying too locate pfc ic as thought it maybe worth a check.

[budm]

Re: Samsung LA32B350F no backlight

See post 16 on where to find out if the PFC IC is getting the VCC Voltage to run or not.

[mrobo]

Re: Samsung LA32B350F no backlight

how to measure it is on the other side of board
should measure with disconnected lamps?

I measured the UP801S = FAN7530 with power board taked out, without conection to the lamps
pin1 = 2V INV
pin2 = 0V MOT
pin3 = 0V COMP (but some votage showed 0.03V)
pin4 = 0V CS
pin5 = 0 ZCD
pin6 = 0 GND
pin7 = 0 OUT
pin8 = 0.6V VCC

[mrobo]

Re: Samsung LA32B350F no backlight

on the transistor QB801 = KTD1347 are the voltages so
E = 0.7V this goes to pin8 which is VCC on UP801 = FAN7530
B = 0.6V
C = 19.2V
the UP801S = FAN7530 does not get VCC on pin8 only 0.6V, then cant give out on pin7 0V which goes to mosfet QP802S = IPA60R600CP 6.1A 600V
does it mean that the circuit with UB802 = KIA393 is not working?
or bad transistor QB801 = KTD1347 ?
or bad UP801 = FAN7530 ?