Sharp LC-52SB55U no image/sound

[ducatilover]

Hello all. Its been a while since ive been on here and im back with another problem on my pops tv.

No image or sound. Power light comes on. You can hear the relay in th PSB click on and off a few times then goes to power & opc blinking. Power light blinks 3x opc blinks 2x. Service manual says its a 5v voltage detect error on pin 33.

I can get any voltage readings on the psb so not usre where to start.

Ive tried the vol/ch and plugging in thing but cant force it to turn on. I see no faint image on screen either. After researching a bit im thinking its the main board or a backlight issue. If its the latter all hope is lost.

Any suggestions on where to start troubleshooting? 2or 3 possibly swolen caps on psb but its not obvious.

Thanks in advance

[ducatilover]

Re: Sharp LC-52SB55U no image/sound

Updated pics wirh voltage readings. I had my leads on the wrong settings.

I get the same readings with the controller board ribbons unplugged and plugged in.

[ducatilover]

Re: Sharp LC-52SB55U no image/sound

Any suggestions?

[R_J]

Re: Sharp LC-52SB55U no image/sound

Power light blinks 3x opc blinks 2x.

Time-out setting reception failure
Start-up confirmation reception failure
Flashes twice

Time-out setting and start-up mode change cannot be
received from the main CPU. (Start-up communication until
time-out setting and start-up mode change is not received.)
Main CPU start-up failure or monitor microprocessor’s reception
failure.

It is likely a main board problem, main board (IC8001) may have poor bga connections, try heating the heatsink for the ic and see if the tv turns on.

If you are going to post voltages , indicate the plug and pin number, then the voltage in standby and when turned on.
ie: main board plug PD
pin 1 ~ 3 UR13v (standby voltage) (on voltage)
Pin 4 ~7 ground
pin 8 AC_DET (standy 0) (on 3.3v)
Pin 9 PS_ON (standby 0) (on 3.3v)
etc.