SAMSUNG PS43E450 totally dead

[sordids999]

hi guys

checking this tv over on first inspection no voltages at all so changed the mainboard which is BN41-01785A but the only one i have is actually the same board but with the ethernet connection version plus the power button board is the wrong connection to the original main board,but upon testing the board i have all voltages now VS/VA/VSC but the screen will not turn on still

so could i test the tcon for test patterns ?
i have added a picture of the tcon

[tw2005]

Re: SAMSUNG PS43E450 totally dead

well, that's a rev 1.3 and if you look at the Sj rev 1.2 you can see the jumpers were above the v-togg but gone on yours and layout is different . i can't work it out comparing the 2 boards I'm afraid

[sordids999]

Re: SAMSUNG PS43E450 totally dead

ok so heres where i am so far :

changed the following: (all from a previous tv i stripped down)
power supply
ysus
xbuffer
plus also tested the buffer board for shorts all fine
using the old mainboard

VA,VS,VSC all good
control boards blinks every second but the tv screen will quickly flash upon turning on but still no picture then restart after about 5 seconds

[tom66]

Re: SAMSUNG PS43E450 totally dead

Jumper holes 3,4 for test pattern on bottom 2x2 right holes.
You will also need to disconnect ribbon cable.

[sordids999]

Re: SAMSUNG PS43E450 totally dead

i tried that earlier tom but no luck

[tom66]

Re: SAMSUNG PS43E450 totally dead

Did you disconnect LVDS? (I meant LVDS last time, not ribbon cable...)

[sordids999]

Re: SAMSUNG PS43E450 totally dead

Yes Tom disconnected the lvds cable from the control board to the main board but the TV done nothing but 'll try again in the morning then report back

[tom66]

Re: SAMSUNG PS43E450 totally dead

Ok, and check if the LED blinks once every 5-7 seconds or once a second.

[sordids999]

Re: SAMSUNG PS43E450 totally dead

With the main connected it blinks once a second then after about 5 secs the TV restarts itself

[tom66]

Re: SAMSUNG PS43E450 totally dead

Is that the LED on the control board?

[sordids999]

Re: SAMSUNG PS43E450 totally dead

Yes

[sordids999]

Re: SAMSUNG PS43E450 totally dead

Hi tom
Tried again this time I have a thin line going across the screen which changes colours but that's it when trying test patterns

[tom66]

Re: SAMSUNG PS43E450 totally dead

Hi tom
Tried again this time I have a thin line going across the screen which changes colours but that's it when trying test patterns

Top to bottom, or left to right?
In dark room, does the screen glow slightly?

[sordids999]

Re: SAMSUNG PS43E450 totally dead

left to right tom but just one single line near the top of the tv i did briefly have more ealrier but cant seem to get it again to do this again
as for a dark room ill have to try it later

[tom66]

Re: SAMSUNG PS43E450 totally dead

That could be a bad buffer IC. Is the panel free of cracks right on the edge?

[sordids999]

Re: SAMSUNG PS43E450 totally dead

hi tom
no cracks in the screen plus i still cant find any shorts in the buffer board

also found 4 shorted IGBTs - RJP30H1 on the old x-main so replaced with a replacement x-main but tv still keeps restarting in a loop mode with the same line going left to right in test pattern mode

[tom66]

Re: SAMSUNG PS43E450 totally dead

Have you tried swapping the Y-main? When you are testing for shorts what pins are you using? Have you checked Vsch across buffer boards (not VSC) if unsure post a picture of the Y-buffer/Y-main connectors.

[tom66]

Re: SAMSUNG PS43E450 totally dead

May be worth eliminating the main board by disconnecting the power connector and jumping PS-ON.

[sordids999]

Re: SAMSUNG PS43E450 totally dead

heres a picture of the buffers tom and the legend on the psu,i have also changed the ymain along with the xmain but before i couldnt get the tv to boot up until i changed the xmain

[tom66]

Re: SAMSUNG PS43E450 totally dead

Ok use the first pin of the top most connector as your test point ground, then run red probe along pin connectors.