Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

[sn4k3]

I have a Sony Vaio VPCEB4Z1E MBX-224, it suddenly stop outputing image to LCD, backlight always works. Tried external monitor and is ok, both VGA and HDMI is able to output image to the external monitor, but internal still without image. Then i buy a new panel but the problem presist. Since i have another equal pc layarround i tried to replace LVDS cable, nothing changed.
After looking schemantics i probe TP's on lcd connector with PC ON, every TP shows voltage.



LCDVCC: 3.3V
ATI lines: 1.2V
INV_: 3.3V
DCBATOUT: 19V

What can be wrong?

[piernov]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

White or black background on the display? No liquid damage?
If black background, you can check every LVDS line (ATI_*) in diode mode to ground, with display disconnected first then connected. All lines should measure the same within 1%.

Might be bad GPU too.

[sn4k3]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

White or black background on the display? No liquid damage?
If black background, you can check every LVDS line (ATI_*) in diode mode to ground, with display disconnected first then connected. All lines should measure the same within 1%.

Might be bad GPU too.

black background. No damage, i have 3 LCDs with same model and try them all.
Diode mode but with PC off in both stages right?

[mcplslg123]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

bad ati gpu. Try mild reflow of ati gpu and then check.

[sn4k3]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

I measure in diode mode, the lines are all +/- 0.478V and others 0.481V (With and without LCD connected, values are the same)

[sn4k3]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

Fixed with reflow, it now have image and works normaly. Thanks

[ktmmotocross]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

u just diagnose problem, no repair

[sn4k3]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

u just diagnose problem, no repair

I know reflow is temporary fix, permanent GPU repair require a new gpu solder in. But this will do for the purpose of this old laptop. Regards

[ktmmotocross]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

reball it

[piernov]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

Why reball? This needs a new GPU.

If it can last a few more days/weeks/months with just a little bit of heat then sometimes it's good enough, but indeed it's not fixed.

[ktmmotocross]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

reball often last much longer than reflow

[sn4k3]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

reball often last much longer than reflow

That's true, but problem with GPUs these days are not the balls most of the times. A reflow and/or reball can fix broken or bad contact with pad/ball joint but we know GPUs goes bad internally and heat expand circuit remove shorts sometimes. Also we can't reball the micro balls from DIE.
In other hand is hard to find brand new GPU's, they will be used and refurbished most of the times on china market (ali, ebay) so don't seens a great solution either. So my preference is reflow first, if it holds great, if not then look futher to replace GPU. I often skip reball because most of the time just end in a time waste fixing nothing that reflow can't

[ktmmotocross]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

even with internal die problem, reball lasts longer

[mcplslg123]

Re: Sony Vaio VPCEB MBX-224 no image but backlight and hdmi works

Yeh, reball lasts longer then reflow but i too dont prefer reballing GPU as this is no solution. It normally comes back to bench within 3-4 months. If i can get a reliable chip, then only i replace-else i return it to customer. New gpu and that too reliable-is something very hard to found and in some series simply not avlbl at all.