Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Would that account for the lack of sound also? Or does the TCON just controll the back light?

[tom66]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

T-con controls image on screen, only. Backlight sync is a feature of some LCDs which improves fast moving scenes.

No sound can be caused by not having the TV on the right input mode or having it muted, etc. This can be hard to verify if you can't see the screen work.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Hmm. Well when the issue occured my wife just turned the tv off. When I turned it back on i flipped through all of the inputs and didn't get any sound out.

I will replace the TCON to see if the picture comes back and then hopefully tht will help my diagnose the sound issue.

Thank you for your help!!

[tom66]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Before you replace the t-con check the fuse on it and any voltage regulators, if you need help post a pic of the t-con.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

There is a pic of the TCON on page one.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

I don't see any fuses (assuming they are labeled "F#") and only one voltage regulator (labeled VR1), which is reading 195 mV, on the TCON board.

[budm]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

CP1 (Circuit Protection) is the FUSE with "O" code on top.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

AH awesome thanks.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Ok Here is what I see.

It looks like LP1 has the "O" in it and CP1 is above that. If measure LP1 I get 1.149 V on both sides. If I measure CP1 I get 1.145 on one side and 0 on the other.

[budm]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

OK, with this better view of the board, it is FP1 with UD printing on top (the designator printings do not line up with the components). Black probe on the chassis, red probe on each end of the fuse, report the DC voltage readings.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

1.126 on both sides of FP1

[budm]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

When TV is turn on and when TV is turn off, if that is the case, the mainboard is not sending the 12V to run the T-CON board. So if the T-CON is not getting the power to run, that may explain why the backlights will not come on.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Those readings were TV on.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

What about the wires that bridge the Main Board and the TCON. I'm not seeing 12V on any of those wires. Is there supposed to be 12V going from the main board to the TCON?

[budm]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

The main board supplies the 12V Voltage through the LVDS cable (cable between the T-CON and the main board). If You check the resistance from one end of the fuse on the T-CON, there should be at least one pin on the main board that will show <1 Ohm, that will be the voltage pin. The voltage top the T-CON is fed through a switched MOSFET which is turn on when the power switch is activated. It can be that the micro controller is not sending the signal to turn on that MOSFET.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Alright I'm gonna need some help with that one.

Is this the area I'm supposed to be looking?

Also what is the button on the Main Board for...just curious.

[WumpusRX]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

Bump. Still confused as to where I am supposed to check the resistance.

[budm]

Re: Insignia NS-LCD42HD-09 No Picture, No Sound W/ Voltages

That pin 51 on the T-CON should have the low resistance read back to the connector on the main board, so if you look at that cable, see how that wire on pin 51 is connected to on the main board.