No reaction from JVC LT-46hw65u

[wylcot]

Hey guys,

So I've got this JVC LT-46HW65U that I've stored in my garage for a while, now.
It stopped working some time ago.



So, I can't figure out what's happening :
The blue light at the bottom of the screen turns on, even a LED on a small board (connected to the remote sensor).

But when I try to swith it on (either with the remote or the side I/O button), nothing happens...

Anyone has an idea idea where to look at, please ?

[dick_barton]

Re: No reaction from JVC LT-46hw65u

If you disconnect the wifi board will it power up.

What voltages do you have on the 14 way and 12 way connectors

[wylcot]

Re: No reaction from JVC LT-46hw65u

If you disconnect the wifi board will it power up.

What voltages do you have on the 14 way and 12 way connectors

Thanks for your help, Dick ! For both threads !

So, no change with WIFI board disconnected.
And I get a 3.4v on pin 7 of the 12-pin connector, not much on the others.
And not much either on the 14-pin one...

It kind of makes sense, doesn't it?

[dick_barton]

Re: No reaction from JVC LT-46hw65u

So you have the standby voltage but nothing else.

Here is a diagram not for your model but may be close enough.

Disconnect the power supply from the mainboard and connect a 1K resistor from pin7 (3.3V) to pin 10 (P_ON) and check the other voltages come up.
If they do then connect a second 1K resistor between pin 7 (3.3V) to pin 12 (BL_ON) and check the backlights are on.

If they all pass then it would look like a mainboard problem,

[wylcot]

Re: No reaction from JVC LT-46hw65u

Waw !
One cannot invent this !

Thanks very much again.
I'll try that and I'll let you know

Just to be sure, I did those tests directly on the supply board, with the connector to main board disconnected.
Did I do it right ?

[dick_barton]

Re: No reaction from JVC LT-46hw65u

Do the test with the mainboard disconnected. You are testing the power supply to see if it is working correctly and the use of the resistors is to mimic the control signals that would be fed to it from the mainboard.

[wylcot]

Re: No reaction from JVC LT-46hw65u

Well that's veeery interesting !

So here, when I connected the STANDBY to P_ON, I got a 24v on pin 1 (I didn't check the others, i thought it was enough a difference).

But then, when connecting STANDBY with BL_ON, nothing...

[dick_barton]

Re: No reaction from JVC LT-46hw65u

Did you connected the standby voltage to P_ON and also at the same time the standby voltage to BL_ON using a 1K resistor for each pin.

You could try connecting the 1K resistor from standby voltage to connector P2 pin 3 (BL_ON) and keep the other 1K resistor connected between standby voltage and P_ON

[wylcot]

Re: No reaction from JVC LT-46hw65u

Nope.
I did P_ON, and then BL8ON.
But as there's only pin7 with the 3.5v, I may have messed up the ting.

I'll try again tomorrow...