Samsung S24B300EL Garbled Screen

[leggot]

I have a Samsung S24B300 that has an issue in which the screen is garbled when first turned on. After times varying from 5-20 seconds the screen resolves itself.

The main circuit board is labeled sa350 and is the version with VGA and HDMI connectors. Anytime the screen is garbled, there is a high pitched noise coming from a cluster of components but when the issue resolves itself, the noise disappears.

I tested the powersupply, it is rated for 14v and it varies from 15 - 14v depending on the board and it also has a center pain making it non standard. However, the powersupply was swapped, and it didn't change anything.

I have powered the unit up with the tcon board unplugged and it, waited 5 minutes and then plugged it in and the issue was resolved, so I think it is isolated to the main board, but I am not 100% sure.

I have tested the main board voltages and they seem fine when the display is garbled, so I don't think that is the issue.

Please let me know if you have any ideas.

And the service manual: http://www.go-gddq.com/upload/2011-12/11122610175323.pdf

 

[davenn]

from what appears to possibly be a temperature related issue with a component
you mite find a can of freezer spray very handy to cool areas off to see if you can make the fault return
once you have narrowed it to an area of components, you can refine your spray efforts more accurately to
individual components in that area and see what you discover

cheers
Dave

 

[jademayer208]

from what appears to possibly be a temperature related issue with a component
you mite find a can of freezer spray very handy to cool areas off to see if you can make the fault return
once you have narrowed it to an area of components, you can refine your spray efforts more accurately to
individual components in that area and see what you discover

cheers
Dave

I think you should do same as Davenn said,I agree

 

[leggot]

So I heated the board up and it seemed to temporarily fix the problem. I am unable to isolate a specific area that seems to be more responsive to heat, but Im pretty sure that this is a heat related issue.

 

[davenn]

so get yourself a can of freezer spray and once the unit is warmed up and working correctly
use the spray in one little burst at a time around the board and wait for it to fail
DONT spray liberally as you will then still have to do finer spraying to narrow the faulty component

EVERY service guy or budding service guy should have freezer spray in his toolkit

Dave

 

[leggot]

It appears as if the main chip is causing the issue. When it is sprayed and then turned on it causes a prolonged time that the garbled screen is shown. It occurs to me that before replacing the chip, it may be beneficial to reflow the board. Is this the right approach or are there other ideas?