Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

[tucocaps]

Hey all,

Have another scammer on Ebay claiming I sent him a "defective" mainboard, when I completely tested the board on a partially working panel/chassis.

The reason why I'm asking, is because of this bit of technobabble he wrote back to me. I was wondering if this is even possible, and if so, how likely it would be that a mainboard would be the culprit.

"This main will turn the set on but there is no pulse width modulation signal to the power supply to turn on backlight circuit"

What is he talking about ? In any case, the backlight was working just fine in my test, else I couldn't have seen the brightly lit , partially damaged panel and picture.

Thanks for any thoughts on this!

[budm]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

There is the PWM signal (0~5V about 200 Hz with variable pulse width to control the backlights lamps brightness).
For the backlights to be on, you need 24Vdc (TYPICAL) for power, PS-ON to turn on the circuit, and PWM signal with at least 10% Pulse width, if the PWM signal is stuck LO (below 10%) then the backlights will not be on.
So you have to verify if his TV has all the needed signals.

[victor_cj]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

Has another defect on inverter module or CCFL backlight, Sharp LCD are known with this problem.

[tucocaps]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

Well, I did test this board, and the backlight turned on for sure. I had a picture, sound, menus, everything. These two were fairly pricey, so I made sure to test them well.

I may have another chassis to re-test this one that I'll be forced to return and more (ebay so horrible for a seller). Just wondering what I'll get back and if it will be damaged.

I was just wondering about his response saying the TV turned on, but not the backlight. Couldn't such a symptom also be a problem with the power supply, that he possibly misdiagnosed as a problem with the mainboard? I happen to have a bunch of these, and never observed this symptom from any of the sets. What does tend to happen with many of these sharps is a flash error code, but that's the result of a short in the panel, so totally different problem. Also, in that case, the set does not power on.

Mainboard in question is Sharp #DKEYMF953FM01

[budm]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

I think they are just doing board swapping until they find the bad board and using you as a board supplier for their experiment.
He has to verify all the Voltages and the all the signals first.

[tucocaps]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

I think they are just doing board swapping until they find the bad board and using you as a board supplier for their experiment.
He has to verify all the Voltages and the all the signals first.

Thanks again , Bud. Also, I totally agree with you on the "experiment" thing, and unfortunately today's Ebay policies are really rigged for these sorts of scamming buyers.

I also realize that without me doing the troubleshooting firsthand, that it's difficult to know what's going on. I was just going to call this jerk, and have a little chat with him , before I wind up being forced into taking back whatever he sends me , and giving him back all his money, paying for shipping again, getting defect on my selling account, etc. SMH.

I guess when it comes down to it, the most important thing is I know I tested it. The best I can hope for is that he at least sends back the main board undamaged so I could sell again ... although I'm not very confident I'll even get that much.

[tucocaps]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

Has another defect on inverter module or CCFL backlight, Sharp LCD are known with this problem.

Victor, what exactly is that problem you show? Is that a problem with the mainboard not sending a signal properly to the backlight, or something else?

[tucocaps]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

Has another defect on inverter module or CCFL backlight, Sharp LCD are known with this problem.

Oh, sorry, I read your post again. Yeah, that's what I was thinking. What I was getting at are what are even the chances of just the PWM to turn on the backlight failing , but everything else working on the mainboard? My guess is not common at all.

[jetadm123]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

Thanks again , Bud. Also, I totally agree with you on the "experiment" thing, and unfortunately today's Ebay policies are really rigged for these sorts of scamming buyers.

I also realize that without me doing the troubleshooting firsthand, that it's difficult to know what's going on. I was just going to call this jerk, and have a little chat with him , before I wind up being forced into taking back whatever he sends me , and giving him back all his money, paying for shipping again, getting defect on my selling account, etc. SMH.

I guess when it comes down to it, the most important thing is I know I tested it. The best I can hope for is that he at least sends back the main board undamaged so I could sell again ... although I'm not very confident I'll even get that much.

eBay polices are definitely "seller friendly" as well as their so-called feedback system, where only the seller can give negative feedback?! Glad to see you're a good seller and did testing before putting the board up for sale. In the future, you can make the buyer responsible for paying return shipping. This might deter some of those "experimenters" purchasing from you and instead get you serious buyers that actually performed some testing on their sets prior to purchasing. Nothing worse than wasting your time with clueless people.

[tucocaps]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

eBay polices are definitely "seller friendly" as well as their so-called feedback system, where only the seller can give negative feedback?! Glad to see you're a good seller and did testing before putting the board up for sale. In the future, you can make the buyer responsible for paying return shipping. This might deter some of those "experimenters" purchasing from you and instead get you serious buyers that actually performed some testing on their sets prior to purchasing. Nothing worse than wasting your time with clueless people.

Thanks, but really it's much worse than that. I've had an ebay account since 99 , and this is the worst it has ever been for sellers.

I'm still just part time on there. I sell some tv parts, and other stuff, but the returns alone make it horrible. Also, they have this "defect" system now, where basically anyone can lose their account, trs status, etc. You can't win with any returns, because the scammers will always claim the item is "broken". If they do, you immediately get a defect on your account. Worse, if you refuse the return, Ebay just steals your money and gives it to buyer, plus they hit you with an even worse defect for that. If you do "hassle free" returns (which is horrible for stuff like TV parts), then they will say it's broken just to get free return shipping. Plus, you'll get loads of frivolous returns when you pick hassle free. It's truly miserable, but I don't know where else people can sell stuff like TV parts with any degree of success?

[jetadm123]

Re: Wondering if one of the gurus could help me out. Sharp LCD mainboard question.

Did not know about the "defect" system. I guess sellers like shopjimmy can survive because they have their own website and can dictate their own policies. Hopefully, you're not selling outside the country as return shipping can be a killer. Can you sell your stuff on Amazon? Are their seller policies any more friendly?