Toshiba 19DL502B totally dead

[budm]

Re: Toshiba 19DL502B totally dead

It is a good one to figure out.

[viera247]

Re: Toshiba 19DL502B totally dead

I think I will just admit defeat!
I removed C711 screwed the board back on and the TV powered on. So that seemed good.

Then I removed board and took C701 out but soldered in to C711 (so now C701 is vacant).TV does not power on.

Removed C711 (C701 as was) so nothing in either C701 or C711 spaces. TV powers up! Touched probe to C731 to check DCV and TV powered off.

C701 back on board with C711 out and TV does not power up (low level clicking sound always accompanies this). Loosened all 4 fixing screws by a quarter turn, switched on a mains and tv powered up!

Decided to attach back cover and switched on mains, nothing but a dead TV.

Then took off back and soldered in C711, TV powered up!!! This hurts!!!!

For the fisrt time in days I tilted the screen upwards to see what might be happening on there. It was bluish but the 'no signal' message was gone and the screen just looked wrong. Plugged in aerial and tv channel sound but no vision. Nothing I did with the remote made any difference to the screen, but the channels did change on sound.

Decided to have cycle ride to escape this madness.

Currently back is off, board attached and as of now the stand by and start up lights are active, screen is just bluish with no message. And that is where my journey has reached.

[budm]

Re: Toshiba 19DL502B totally dead

Well that is really confusing with that C711. At this point just for testing, I would would remove all four of those safety caps, put all the screws back in place and hopefully the TV will start up, then check the or reseat the cable between the main board and the LCD panel to see if you can get the pictures back on the screen.

[viera247]

Re: Toshiba 19DL502B totally dead

Well that is really confusing with that C711. At this point just for testing, I would would remove all four of those safety caps, put all the screws back in place and hopefully the TV will start up, then check the or reseat the cable between the main board and the LCD panel to see if you can get the pictures back on the screen.

They are all off now. TV powers up but screen remains dull blue. Connector is attached.

[budm]

Re: Toshiba 19DL502B totally dead

Can we see the pictures how the LCD panel is connected to the main board?

[viera247]

Re: Toshiba 19DL502B totally dead

Hows this?

[budm]

Re: Toshiba 19DL502B totally dead

I cannot see how the LCD panel is connected to the board.
We need to find out if the LCD T-CON is getting the signals and the Voltage to run or not.

[Diah]

Re: Toshiba 19DL502B totally dead

sorry to tell and you are following of fault which had story of screw...
you have cracking at layer print of yours Vestel 17pw05-3, it cant noticed just with eyes unless the boards waved , and each time you take it out in hand and back the crack growing to reach join point of SMD parts.

[budm]

Re: Toshiba 19DL502B totally dead

He should be able to push on the board now with a wood or plastic stick with all the screws in place to see if it will cutout the power, I hope that will be it.

[Diah]

Re: Toshiba 19DL502B totally dead

if he push from top of board the crack will remain more open. it should opposite push from down to top of the board

[viera247]

Re: Toshiba 19DL502B totally dead

if he push from top of board the crack will remain more open. it should opposite push from down to top of the board

I think you are correct about this as it seems consistent with what we have been finding. It is not however possible to push from underneath as there is just no space.

By fully reassembling (including the casework) and having very carefully tightened all 4 PSU board screws so that they felt secure but not too tight to cause any evident board distortion I can achieve a TV that powers up and which can receive a signal through the aerial which gives sound but no picture. The LCD appears backlit only.

As mentioned previously I know that the screen did work okay and all the connectors that I previously disconnected are clearly in place.

So this project still has some life in it with a new T Con board problem to resolve?!!

[viera247]

Re: Toshiba 19DL502B totally dead

I cannot see how the LCD panel is connected to the board.
We need to find out if the LCD T-CON is getting the signals and the Voltage to run or not.

I think it is these you were referring to? Going from main board to top of casing. The main board on was disconnected as part of the earlier diagnostic exploration and I have checked again that it is secure.

So what do you suggest I should check?

[budm]

Re: Toshiba 19DL502B totally dead

The LCD panel may bot be getting the Voltage to the panel to run (the panel probably has integrated T-CON which will not be replaceable).
There should be enough room to put thin flat plastic or wood under the board to flex the board. I would still try to flex the board from the top.
BTW, is there insulation sheet under the board? If is the board is <6mm above the metal chassis it will require to have insulation sheet at least around the hot side of the circuit to meet safety compliance.

[budm]

Re: Toshiba 19DL502B totally dead

I think it is these you were referring to? Going from main board to top of casing. The main board on was disconnected as part of the earlier diagnostic exploration and I have checked again that it is secure.

So what do you suggest I should check?

the T-con is under that metal shield and there should be a small SMD fuse close to that LVDS connector.

[viera247]

Re: Toshiba 19DL502B totally dead

What does that fuse look like please?

This is the area around the connector if that helps. Apologies for quality, taken on phone.

Think I have found it. It is on the underside and shown as F1

[budm]

Re: Toshiba 19DL502B totally dead

Pictures are WAY out of focus for me to see anything clearly.

[viera247]

Re: Toshiba 19DL502B totally dead

Pictures are WAY out of focus for me to see anything clearly.

I saw that and replaced with above as you were posting.

[budm]

Re: Toshiba 19DL502B totally dead

F1 is the fuse, it should have either 5VDC or 12Vdc (depends on the LCD panel model) at both ends with ref to the chassis GND.

[viera247]

Re: Toshiba 19DL502B totally dead

Shows zero so that's it I assume.

[budm]

Re: Toshiba 19DL502B totally dead

Shows zero so that's it I assume.

0VDC, so the main board is not sending the Voltage to the T-CON board, more troubleshooting required.
BTW, what is the LCD panel model number so we can look up the spec sheet to find out what the DCV requirement is for the T-CON?