Sanyo DP42848 sound ok but no picture...bad t-con control?

[supremacy13]

I have other TV its Sanyo DP42848. I replaced both master and slave inverters on this TV. It power up for like 2-3second then went off. I use my flashlight and I can see something on LCD. That mean the backlight went off, does it mean T-Con control is bad?

Thanks
Bryan

[tom66]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

No, it likely indicates a fault with the inverter boards. Did you connect the wire from master to slave? Is there a control cable from the T-con to one of the inverters?

[supremacy13]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

Here picture I draw and lines...tell me anything am I missing? I know this is the right way connect but still no back light on.

[budm]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

Can we get closed up pictures of the power supply board so we can see the labels on the connectors to see which pins ae for? I am looking for 24Vdc, BL_ON, etc.

[supremacy13]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

here 2 pictures

[tom66]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

Using a multimeter on the DC 200V range, check the "24V" to case ground (red probe in 24V and in volts-ohm; black probe in a spare screw hole (make sure at least the power board is screwed to chassis for this test) and seated in COM.

[supremacy13]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

look like power supply has no 24v to inverters, my meter reading show 0.00.

[budm]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

Are you getting this 0V on the 24V line after the TV turns on and then goes black screen?

[supremacy13]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

it went 23 volts then drop 0.00 after turn it on

[tom66]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

Almost/exactly 0V after screen when blank? Also only 23V when running?

[supremacy13]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

its not drop from 23v to 0.00 right away. Meter reading show like time count down. 23 then 20 then 18, then 14, 9, 4, then 0.00 and it became -0.01 sometime -0.02.

Tried to find any damage on power supply. It dont show any of sign of damage. I think power supply is bad. Im not sure.

[budm]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

Can you look at the PS_ON pin to see if it stays at 3VDC or higher when the 24V starts dropping?

[DakotaKid]

Re: Sanyo DP42848 sound ok but no picture...bad t-con control?

I have the exact same TV with exact same problem, I just haven't gotten to it yet. However, if it would help, I can get any readings or measurements from mine to supplement the troubleshooting going on here. I won't hijack the thread but hope I can maybe help.
DK