JMB JT014001/01 main board problems

[Bloopeta]

Have been given this today, wont switch on, tries to but fails, standby light flashes, keeps trying in loop without success.

If apply heat to main processor on mainboard, it will come to life, however as it cools it goes off again.

Unfortunately the screen has some quite bad scratches on it, the TV is not in the best of condition, and didnt come with remote, so not worth spending money on a replacement mainboard, just wondering if anyone could offer any advice, tips/tricks to get the original one functioning correctly, then can possibly give it to someone in need.

[nomoresonys]

Re: JMB JT014001/01 main board problems

Only cheap fix is bga reflow, may not last long if it works.

[Bloopeta]

Re: JMB JT014001/01 main board problems

Only cheap fix is bga reflow, may not last long if it works.

How would I go about doing that to possibly make it last as long as possible, any tips other than just the usual application of heat?

As I said, Im not looking to do it to sell or anything, was just gonna try n fix it to give to someone who needs it, so lasting any amount of time would be a bonus. Just seems a shame to scrap it

[nomoresonys]

Re: JMB JT014001/01 main board problems

Thread there, there's lots of videos on you tube also, involves getting the solder under the bga chip to melting so it reconnects, then I would install a fan or something to try to keep it cool: https://www.badcaps.net/forum/showth...ght=bga+reflow

[nomoresonys]

Re: JMB JT014001/01 main board problems

One there he's working on a graphics card or such but same concept, note how he says if you get it too hot it will kill it: https://www.youtube.com/watch?v=HrAAOiFJR9s

[diif]

Re: JMB JT014001/01 main board problems

Having done several reflows I've yet to have one come back. If it's lasted x years, there's no reason it shouldn't last another x years until it fails again. It will benefit from an aluminium or ceramic heatsink, a fan is not required.

It's not ideal to try and reflow the processor with the rest of the board cold, preheating it over a stove to about 100c before hand will reduce the chance of thermal shock.

[Bloopeta]

Re: JMB JT014001/01 main board problems

Cheers guys Ill give it a whirl in the morning and report back

[nomoresonys]

Re: JMB JT014001/01 main board problems

Fans have been used with great success and if you never had one come back then you should patent your technique, because they usually don't last 6 months.

[diif]

Re: JMB JT014001/01 main board problems

The heatsink on the Veatel's is either non existent or it's a flexible strip a solid heatsink is more than sufficien. I'm speaking from first hand experience.
No need to patent, there's nothing special in the way I do it, I do use a rework station though and decent flux. I tend to reball most of the time though, depends on the customers budget.
There's no reason a reflow should fail any quicker than it originally failed if the usage is the same.

[nomoresonys]

Re: JMB JT014001/01 main board problems

" I tend to reball most of the time though" OK the answer is in the explanation.

[nomoresonys]

Re: JMB JT014001/01 main board problems

Excessive heat is the culprit, if this problem is not addressed with some form of cooling, then a reflow will not last long, just the facts. Yes a heatsink would be easier to install if there is room, some tvs are ultra slim tho, ceramic heatsinks are the ones to use, obviously.