LE40M86BD switching off/on

[Dodgexander]

Re: LE40M86BD switching off/on

That Bordeux-Plus is a Very common mainboard!

Cant understand why you cant find one!

Just get one for a 32" or 37" LCD (They are also used in Plasma--but havent the BL control O/P on those) and set it up for the 40" panel--Easy!
--Did exactly that same thing today!

That's good to hear but I can't find any matching my board number:BN94-01264b do you happen to know which other boards will work? There's a few on eBay so it would help to know which other numbers will work well in my set.

[CapLeaker]

Re: LE40M86BD switching off/on

that is a better choice.

[Alastair E]

Re: LE40M86BD switching off/on

That Bordeux-Plus is a Very common mainboard!

Cant understand why you cant find one!

Just get one for a 32" or 37" LCD (They are also used in Plasma--but havent the BL control O/P on those) and set it up for the 40" panel--Easy!
--Did exactly that same thing today!

[Dodgexander]

Re: LE40M86BD switching off/on

I checked out the visual difference between that board and mine. The main is the side panel. The one on eBay is missing the side panel ports like hdmi 3 svideo etc.The other missing sockets aren't actually used on my board despite being there. I wonder if it matters not having the side panel, I don't use it anyway. There are more expensive boards like this that look more similar but cost twice as much, I may have to just buy the expensive one instead.

[CapLeaker]

Re: LE40M86BD switching off/on

You are correct. Some sets have 3 different panels, 3 different part numbers for the same board. Some are interchangeable / compatible. Hard part is to figure out if that board you could be getting can do that or not. You never know until you try or play chicken. I guess that depends on how much money that new board is.

If I compare that board with your board, then there are already some plugins missing on the board. Not knowing where they go and what they do, I would say probably not. However if it is just because a combo DVD player was plugged in there, who cares.

[Dodgexander]

Re: LE40M86BD switching off/on

Yeah the inverter voltage is on a different connector. I've tried jumping both BLon and PSon before but at the same time. Not with each other but with their respective standby. The set wouldn't start and made a fuzzy noise. I can try it only with the inverter cable though. What would trying it conclude btw?

I found this main board for the 46 inch m87 which I thought was just cosmetically different. I wonder if it would work.

I'll give the board a clean then and heat it up. I wish I had a heat gun but I guess I can use the oven for a bit.

The main thing that scares me is I think it's possible my set has an AUO board and not a Samsung. It makes me wonder if some sets come with different panels hence the different part numbers?

[CapLeaker]

Re: LE40M86BD switching off/on

Power on off is the PSON. However I don't see BLon, so I guess it is on another connector? I am just on a tablet right now so I can't really see. If PSON doesn't gradually drop, just disappears and then reappears, your options are limited.
For me I'd be cleaning it really good, then bake it a little bit and try again.
Unfortunately, the BLon and PSON is generated on the main IC. So nothing much you can do on the main board.
You could try removing the BLon pin and jump with a 1k resistor from STBY voltage to BLon. Make sure the BLon pin is disconnected, you do that want to backfeed any power to the main board.

[Dodgexander]

Re: LE40M86BD switching off/on

BLon is the turn on signal for the inverter. BLon and PSon should be more than 2V. So yes... if you losing PSon (voltage slowly dropping off) then the TV turns off. At this point you got nothing much to lose on that board.

If you could find another board of the same series TV with the same size screen, just maybe more or less extra features on the main board itself, you could get one of those. We did "upgrade and downgrade" a few TV's like that.

Thanks. The PSon is the same as pin one on my screenshot?
If so it doesn't gradually drop. The tv turns off and on and between those moments the voltage suddenly drops to nothing and after jumps back to about 1.94.

It's the inverter power that drops gradually by comparison. It's usually reading over 5v but as the set powers off it slowly goes to 0 and slowly comes back as the set turns back on again.

If I get a boards listed for a different screen size but for the same model tv can adjustments be made in the service menu to suit the panel size?

[CapLeaker]

Re: LE40M86BD switching off/on

Sorry I realised I missed this post. I don't have anything to clean it with but I can get some.

During the cycle power on loses voltage completely. It goes from 1.9 to 0 then when it comes on again the voltage comes back.

Standby stays at 5.2v even when the set powers off

I'm guessing by BLon that's the inverter power? If so that loses power and standby power gradually, it goes to 0 and then comes back again as the set turns back on again.

BLon is the turn on signal for the inverter. BLon and PSon should be more than 2V. So yes... if you losing PSon (voltage slowly dropping off) then the TV turns off. At this point you got nothing much to lose on that board.

If you could find another board of the same series TV with the same size screen, just maybe more or less extra features on the main board itself, you could get one of those. We did "upgrade and downgrade" a few TV's like that.

[Dodgexander]

Re: LE40M86BD switching off/on

ps-on is generated by the main board and sent to the power supply,1.9VDC is too low for the PS-ON,it could be a cap related issue on the main board

This is the pin arrangement for the test points. Is the PS-On you describe power on/off as shown on this schematic? It always measures 1.93/1.94 even when the set isn't turning itself on and off, so this is definitely a motherboard fault and not power supply related? Thanks

Is there any way for me to test whether my bad soldering work has caused a problem on the board? Like measuring the voltage coming out of the circuit where the two caps I replaced are?

by Cleaning i was meant ito say it may show up a cold solder joints etc under some of that white staining etc you may have to look under a magnifier though.

Okay I will buy some Iso-Propyl Alcohol and give it a clean! thanks

Doesn't look to good trying to find a replacement motherboard though, just can't get the exact model number anywhere. wondering if I should risk a similar board replacement.

Is it possible the eeprom could be at fault? If I obtain a board for the same model tv can I program the service menu for it to work? I've read about people being able to do that online.

[vinceroger69]

Re: LE40M86BD switching off/on

by Cleaning i was meant ito say it may show up a cold solder joints etc under some of that white staining etc you may have to look under a magnifier though.

[multimeter]

Re: LE40M86BD switching off/on

ps-on is generated by the main board and sent to the power supply,1.9VDC is too low for the PS-ON,it could be a cap related issue on the main board

[Dodgexander]

Re: LE40M86BD switching off/on

Thanks for the help!
It seems I'm unfortunate to own a set that has a rare board. I've searched via a proxy on shopjimmy and there's no results for my board number. There's no direct north American equivalent to the m86 either. The 65f and 61f seem most similar. But even boards listed on eBay here for my exact same set have different part numbers.

I don't have any ipa but I can buy some to clean the board. Not sure it's worth it if I'm replacing the board?

I'm scared I've damaged where I've fitted the two replacements smd caps as one of the copper pads beneath one of the caps broke, a bit of the circuit board came lose and I had to glue it back down. But then I guess it wouldn't work or be worse if I'd have damage it.

Alas when I search for the board number here I get some results in shops but they are all sold out. eBay doesn't have any at all. I wish we did have a shop as good as shopjimmy here but we don't

I'll give flexing the power board a try. The switching off/on doesn't always happen straight away, sometimes it doesn't happen for 20 mins. The other day I switched the set on and it didn't do it at all and it must have been on for half an hour.

I'm very grateful for all the help guys, means a lot. The set has been sitting on my dining room table for 3 weeks now and I'm trying hard to get it sorted. It didn't help catching the flu half way through though!

Edit# tried flexing the board and it didn't provoke switching off/on. Strangely after leaving the set off for a while it turned off but didn't automatically turn back on. I could hear the power supply buzzing when it happened do it definitely was "on" but readings from the cable to the motherboard at this time were all really low voltage.

I dunno. Given, the pics aren't the best, but it certainly looks like the back of the main board was wet at some point of its time.
Clean it off with 99% alcohol and a toothbrush etc. dry it, install it and try it again.

Also what does STBY voltage, PSon and BLon pins do on the power supply when the set goes into the cycle? If you loose PSon during that cycle, you have a main board problem.

What is underneath the metal shield on the front of that main board? Any caps in there?

Sorry I realised I missed this post. I don't have anything to clean it with but I can get some.

During the cycle power on loses voltage completely. It goes from 1.9 to 0 then when it comes on again the voltage comes back.

Standby stays at 5.2v even when the set powers off

I'm guessing by BLon that's the inverter power? If so that loses power and standby power gradually, it goes to 0 and then comes back again as the set turns back on again.

[multimeter]

Re: LE40M86BD switching off/on

sounds like a cold joint on the power supply to me,try flexing the power suppy with a insulated plastic rod or simular,does it make the fault re-occur ?

[CapLeaker]

Re: LE40M86BD switching off/on

SJ doesn't list that board... Isn't there something equivalent to SJ in the UK?

[vinceroger69]

Re: LE40M86BD switching off/on

I wonder if budm or one of the members abroad will look on shopjimmy for you and see what they list as substitutes for your BN94-01264b board (as shopjimmys blocked uk ip address etc so its hard for us too search now) you also mention you have had the firmware updated by samsung in the past i wonder if you cant find a board if its worth trying a new eeprom chip if you can get one maybe a more experienced member will know if a bad eeprom chip can cause your issue your having. It may also be advisable if you have any ipa etc just clean the back of the board of etc it may not be water damaged but ive not saw one with that much staining on etc before.

[Dodgexander]

Re: LE40M86BD switching off/on

It's strange because I've seen boards on eBay from the same tv model but they are a different board number. The one I found for a good price is for the 46 inch version of the tv but the number is different.

Edit# this is a different number but is for exactly the same model as my tv. http://pages.ebay.com/link/?nav=item...218263&alt=web

I've had the set since new and all that's ever happened to it is the firmware was updated by a Samsung engineer. This is the first time the set has been opened! How can mine have a different motherboard sticker to others! How can I know if other boards will work?
My board is BN94-01264b and I can't find any with that number.
The one on eBay which is from the 46 inch version is BN94-01490e

[CapLeaker]

Re: LE40M86BD switching off/on

It should be the same board #, but some others are compatible. I wouldn't risk that unless I would be 100% sure.

[Dodgexander]

Re: LE40M86BD switching off/on

Can I buy a different # board from say the 46" version of the same tv?

[CapLeaker]

Re: LE40M86BD switching off/on

Whoah water damage? Really? Wow I didn't expect that. Where has it come from it's been mounted on our living room wall!

I dunno. Given, the pics aren't the best, but it certainly looks like the back of the main board was wet at some point of its time.
Clean it off with 99% alcohol and a toothbrush etc. dry it, install it and try it again.

Also what does STBY voltage, PSon and BLon pins do on the power supply when the set goes into the cycle? If you loose PSon during that cycle, you have a main board problem.

What is underneath the metal shield on the front of that main board? Any caps in there?