Sanyo LCD-40R50F lcd tv shorted mainboard - need help

[jackal68]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

okay...after much testing with the limited equipment I have (no leak seeker!!), I found another short on an IC labelled 3482. I peeled the label to try to read the actual ic number, but I can't make it out (it is on the left lower corner of the 2nd picture attached and the actual ic is the 1st and 3rd pictures). However, after taking off the ic, the pads on the board were still shorted....so that goes that try.

Since the ic is far from the other shorted components, I tried tracing the circuit...and I realized that the connections seem to go through the big main chip with the heatsink at the centre. After detailed inspection, the chip 'looks burnt'.....can anyone confirm these are burnt marks on the chip?(4th and 5th pictures).

thanks

[Peter Chiu]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Ok I know, but first teach me, how to post your pictures,just like you did . I am learning......

That is EEprom, seldom have any problem. If yes, U need to program it.
Never head they burn out .....but sometime they will lost their memory ....the mark is from the label sticker..... maybe is your main processor .........

https://cdn.badcaps-static.com/pdfs/...ce995b0676.pdf

[newtothis]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Ok I know, but first teach me, how to post your pictures,just like you did . I am learning......

That is EEprom, seldom have any problem. If yes, U need to program it.
Never head they burn out .....but sometime they will lost their memory ....the mark is from the label sticker..... maybe is your main processor .........

https://cdn.badcaps-static.com/pdfs/...ce995b0676.pdf

Sorry bud but that looks like heat damage to me

[Peter Chiu]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

N101 (8 pins IC)never burn . N102, please take off the heat sink, clean up ,give us another picture....N102 can be glue it back with silicon.

[CapLeaker]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

That main IC doesn't look healthy. Now you got nothing much to loose, take the heat sink off clean the ic and have a look.

[newtothis]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

N101 (8 pins IC)never burn . N102, please take off the heat sink, clean up ,give us another picture....N102 can be glue it back with silicon.

Anything with an electrical current can burn under a short, Components fail no matter what they are so nothing can say for certain that something cannot burn.

By the look of that IC the thermal compound is visible at one side but looks to me as if it doesn't have a full thermal coverage of the IC... Indeed a short could burn it out

[jackal68]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

I have tried taking the heatsink off but it won't move. I even heated it up to see if the thermal paste would loosen up....nothing. Do I just force it out of there with a flathead screwdriver?

[newtothis]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Can be real stubborn to get those things off!

Try scraping just at the edge of the heatsink where it appears the surface has blistered on the IC... you should be able to tell if its the IC or not that has burnt up.

My betting it is... BGA components that have been heated too quickly show that as they delaminate

[jackal68]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Okay....i popped the heatsink off....took off a chunk of the chip....it looks burnt to me....what do you guys think? If the chip is gone....is the main board toast or is there a way to replace this chip?

[jetadm123]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Afraid the main chip is burned out. Don't waste any more time on this board. Start looking for a new main board.

[newtothis]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Yeah that is definitely toast, No way would the IC of parted like that if it hadn't burnt.

I agree to get a new main, Though I am not saying it cannot be repaired.

[jackal68]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

The thing is....I can't find this main board anywhere....that's the reason why i'm trying to repair it.

[newtothis]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Ok then we need to find that part number somehow, Clean the top of the IC and see what label is left

[jackal68]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Here it is. Do I need to program this chip if I find it???

RTD2933H
A5F68S2
GB17D

[budm]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Replacement board:
http://www.electrorepairshop.com/6ma...anyo-lcd40r50f
http://www.usefulparts.com/tv-parts/...d-26r40-lcd-tv

569MA0101A

[Peter Chiu]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

.........Here it is. Do I need to program this chip if I find it??? .....
No that is a video processor... they use EXT EEPROM to customize for different brand ...

......LOOK that...... TAIWAN........O....O...........Oops!

Before I naturalize to US , I come from Taiwan. I love HER...so, Hope! this is not a Crap...God bless the chip not burn out ....can resist that heat .....Like I can resist all the racialism....Just do best I could......

[Peter Chiu]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

the gate oxide in the floating-gate transistors gradually accumulates trapped electrons. The electric field of the trapped electrons adds to the electrons in the floating gate, lowering the window between threshold voltages for zeros vs ones. After sufficient number of rewrite cycles, the difference becomes too small to be recognizable, the cell is stuck in programmed state, and endurance failure occurs. The manufacturers usually specify the maximum number of rewrites being 1 million or more.
Flash memory is a later form of EEPROM. In the industry, there is a convention to reserve the term EEPROM to byte-wise erasable memories compared to block-wise erasable flash memories. EEPROM occupies more die area than flash memory for the same capacity, because each cell usually needs a read, a write, and an erase transistor, while flash memory erase circuits are shared by large blocks of cells (often 512x8).
Newer non-volatile memory technologies such as FeRAM and MRAM are slowly replacing EEPROMs in some applications, but are expected to remain a small fraction of the EEPROM market for the foreseeable future.
Most NOR Flash memory is a hybrid style—programming is through hot carrier injection and erase is through Fowler–Nordheim tunneling.

...........Anything with an electrical current can burn under a short, Components fail no matter what they are so nothing can say for certain that something cannot burn.........


I'm servicing the electronic field more than 37 years , never find A shorted EPROM or EEPROM. .....Maybe just not easy to burn, because they low voltage usage.....If I'm wrong anybody..... PLS let me know.........

[newtothis]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

the gate oxide in the floating-gate transistors gradually accumulates trapped electrons. The electric field of the trapped electrons adds to the electrons in the floating gate, lowering the window between threshold voltages for zeros vs ones. After sufficient number of rewrite cycles, the difference becomes too small to be recognizable, the cell is stuck in programmed state, and endurance failure occurs. The manufacturers usually specify the maximum number of rewrites being 1 million or more.
Flash memory is a later form of EEPROM. In the industry, there is a convention to reserve the term EEPROM to byte-wise erasable memories compared to block-wise erasable flash memories. EEPROM occupies more die area than flash memory for the same capacity, because each cell usually needs a read, a write, and an erase transistor, while flash memory erase circuits are shared by large blocks of cells (often 512x8).
Newer non-volatile memory technologies such as FeRAM and MRAM are slowly replacing EEPROMs in some applications, but are expected to remain a small fraction of the EEPROM market for the foreseeable future.
Most NOR Flash memory is a hybrid style—programming is through hot carrier injection and erase is through Fowler–Nordheim tunneling.

...........Anything with an electrical current can burn under a short, Components fail no matter what they are so nothing can say for certain that something cannot burn.........


I'm servicing the electronic field more than 37 years , never find A shorted EPROM or EEPROM. .....Maybe just not easy to burn, because they low voltage usage.....If I'm wrong anybody..... PLS let me know.........

Its simply a case of if a component other than the one in question fails allowing higher current it can kill it, Simple as that really

[Alastair E]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

Only large processor type chip Ive seen sort of short and actually smoking was in a sat-nav....

Strange to see! Doesn't happen often I guess--but Nothing is immune to burning up and letting out the Magic Smoke, and once that Magic Smoke's escaped--it doesn't work anymore....!

[CapLeaker]

Re: Sanyo LCD-40R50F lcd tv shorted mainboard - need help

The thing is....I can't find this main board anywhere....that's the reason why i'm trying to repair it.

With that IC off the board, it the short gone now?