Samsung LE32A456 standby light flashing

[finntricky]

Got this tv a week ago no power/dead, took it home and took the back of to find no power supply in it, orders a P.S. from eBay, and it turned up today, sold as fully working and tested, guess what, it ain't,LOL
After installing this board I have standby light, and try to turn on, but get 5 flashes of the light and then goes back to solid light, done a few tests and only get the 5volt standby and nothing else at all, I have also tried to force the supply on using standby and P.S. as marked on the board and still got nothing, any ideas on this ?

[sordids999]

Re: Samsung LE32A456 standby light flashing

Is the power board BN44-00214A ?
im sure its the same fault with the LE32A457 with reference to a post i saw before try removing all of the glue as much as you can because this can become conductive over time
and check the solder joints on QB802 i think ?

[budm]

Re: Samsung LE32A456 standby light flashing

+1 on removing all the GLUES.
BTW what DCV do you have for the command signals feeding this power supply board?

[finntricky]

Re: Samsung LE32A456 standby light flashing

thats correct board, and yes i read the posts about that, and i have already done QB802 it was broken joint on this,
still not getting any 12 volt from it for the main board ? just the 5 volt SB pin

[budm]

Re: Samsung LE32A456 standby light flashing

thats correct board, and yes i read the posts about that, and i have already done QB802 it was broken joint on this,
still not getting any 12 volt from it for the main board ? just the 5 volt SB pin

The 12V and the 24V are generated by the same power transformer TM801S and the drive circuits, for that section to work it needs the PFC Voltage booster circuit to function to provide about 400VDC (measured between the two legs of the main filter cap CP803 when PS-ON is present)
So you need to find out of the PFC is working or not.
The common failure for not having 12V/24V is due to the cap CM808 (18nF 630V) that lose its capacitance.

[finntricky]

Re: Samsung LE32A456 standby light flashing

main cap gives 334 volts in standby, and no change when trying to turn on, the cap CM808 reads 18.8nf, so maybe transformer is the problem ? not sure how to test it

[budm]

Re: Samsung LE32A456 standby light flashing

The PFC Voltage booster is not working, you need to get that working first. See the diagram so you can check and see if the PFC IC is getting the correct Voltage to run.

[finntricky]

Re: Samsung LE32A456 standby light flashing

thanks bubm, but this is now going where i have never had to go, and im feeling very lost when it come to reading and understanding the drawings,

[vinceroger69]

Re: Samsung LE32A456 standby light flashing

this is what is in the kit for missing pfc voltages it may help in fault finding
http://www.ebay.com/itm/Samsung-BN44...-/271780921354
Symptoms: Missing Power Factor Correction and/or run voltages
Description Quantity Board Location
Capacitors 6 CM851, 852, 856, 858, 861, 868
Transistors 3 QM801, 802, QP801S
Integrated Circuits 2 ICM801S, ICP801S

[finntricky]

Re: Samsung LE32A456 standby light flashing

thank you vinceroger69, that is a great help, i will have a look later when i get home.

[finntricky]

Re: Samsung LE32A456 standby light flashing

update, found the fault, it was QM802, could not see while it was on the board, but middle leg had rotted though and just fell of on removal, i may of snapped it while removing the glue, replaced with a known good unit, and it fired up, been running for half hour now, thanks for all the help guys,

[sordids999]

Re: Samsung LE32A456 standby light flashing

Anyone had a similar fault on this model where the volume bar goes up by itself and channel changes etc etc
also cleaned all the bad glue from the power supply

[flocko]

Re: Samsung LE32A456 standby light flashing

unplug side control buttons and use remote if it clears the problem fit new side button ? common fault with this model

[sordids999]

Re: Samsung LE32A456 standby light flashing

opps must have missed this Flocko sorry
At the moment its working fine firstly used the Factory reset in service menu still was failing so tried a eeprom reset in service menu tv working two days now
but ill check the side button anyway