samsung LN40B500P3F

[kueberco]

Can anyone help me with obtaining a service manual for a LN40B500P3F samsung tv? Thank you!

[ryan74]

Re: samsung LN40B500P3F

I just got one of these. Mine won't turn on but I do have stby5.3v on psu. Also tested 13v from 3 leads and 5.3v from 2 leads on con 29/30
My first guess is the tuner card is bad since everything runs through there.
The Guy said a lightning strike took it out.

[budm]

Re: samsung LN40B500P3F

Does the backlight come on when you unplug that ribbon cable from the inverter/power supply board? Inverter ON/OFF pin should have >3V same for PWR ON/OFF PIN when TV is turn on. Your DC readings are OK.

[ryan74]

Re: samsung LN40B500P3F

yes the backlight came on when i disconnected the ribbon from psu.
i reconnected it and checked
pwr on/off 1.17v
inv on/off .09v
i assume these are low because it wont turn on yet?

[tom66]

Re: samsung LN40B500P3F

This is a Black Friday special, a variant of the LN40B530 I believe.

Uploaded manuals here:
http://tgohome.com/ServiceManuals/?d...&Search=Submit

Please note, there are at least two variants of this chassis, N70A and N64B. Check the model code precisely for the right variant.

[budm]

Re: samsung LN40B500P3F

Your power supply/inverter board is OK, you will have to troubleshoot the main board next, the inverter ON/OFF signal from the main board is not working, it is stuck in the LOW (Off) mode.

[ryan74]

Re: samsung LN40B500P3F

model code is
LN40B500P3FXZA
I guess i dont see the manual or its not there

here is a closeup of main board if that helps. I dont know if theres much i can do but the only main board i could find was $90 so hopefully i can fix it with your help.
main board is BN94-02746K

[tom66]

Re: samsung LN40B500P3F

Wow, tiny main board.

Check the manuals I linked to, they are B530, but they might be the same.

[ryan74]

Re: samsung LN40B500P3F

maybe im too tired. i understand the test process for main board i think but the test points dont seem labeled the same as the manuals. all the test points i see are marked TP*** (3 digit numbers)
if im going to figure out whats wrong i need to be walked through this one. smallest board i have attempted to fix and i dont know what half the parts are on it lol.....

[ryan74]

Re: samsung LN40B500P3F

anyone have a main board for samsung ln40b500p3f
board number is: bn94-02746k (alternate bn94-02746y)

[tom66]

Re: samsung LN40B500P3F

http://www.populargaragesale.com/pgs...product_id=747 - Says not working? Or maybe untested?
http://www.ebay.com/itm/SAMSUNG-LN46...-/200828359389 - Insane price!
http://www.ebay.com/itm/SAMSUNG-LN46...-/200828359389 - Same part from Emerson TV?

[ryan74]

Re: samsung LN40B500P3F

The links you posted look like the right part but numbers don't match. Are you sure, these are compatible.

[tom66]

Re: samsung LN40B500P3F

The links you posted look like the right part but numbers don't match. Are you sure, these are compatible.

I am not sure at all when it comes to Samsung and board compatibility, it's not obvious.

[budm]

Re: samsung LN40B500P3F

You can contact Shopjimmy to see when he will have them instock again:
http://www.shopjimmy.com/catalogsear...ng+ln40b500p3f

[ryan74]

Re: samsung LN40B500P3F

I contacted shopjimmy they couldn't say whenor if they would restock.
I also contacted samsung support. They knew less than me. They were unaware of any replacment but shopjimmy says either bn94-02746k or bn94-02746y will work.
Unfortunatly I cannot find either in stock for less than $90+shipping used and I forgot where I found it. Lol

[ryan74]

Re: samsung LN40B500P3F

Your power supply/inverter board is OK, you will have to troubleshoot the main board next, the inverter ON/OFF signal from the main board is not working, it is stuck in the LOW (Off) mode.

So if it is stuck in low mode can you help me troubleshoot/test this?

[gilly1984]

Re: samsung LN40B500P3F

Is it possible to force a few volts into it to test it?

[budm]

Re: samsung LN40B500P3F

The transistor on the main board is on so the output will be low (the transistor may be told to be on due the bad processor or bad transistor), the pull up resistor is in the power supply board thst is why when you remove the cable to the main board, the power supply and the backlights turn on due to the pull up resistors on the power supply board are pulling the pin high.
What we need to do is to find out next if the only circuit that is bad is the Inverter ON signal or it may have more than one problem. Waht you can do is to disconnect the Inverter on wire only for the the board so the backlights will come, if everything else is OK, hten you should be able to see the pictures and sound from the TV. If not, then you have multiple problems with the main board. The whole purpose of the backlights is to give the light source so you can see pictures, it does nothing else, so try that.

[ryan74]

Re: samsung LN40B500P3F

added a few more pics above

[budm]

Re: samsung LN40B500P3F

You can cut the wire then you can splice it back together when we fix other problem, just make sure to cut the right on and also tape up the ends.