Westinghouse TX-47F430S ps replacement

[minki12]

Hi All,
New to the forum here so i will try to keep my post clear. I was given a 47" westinghouse tv TX-47F430S that would not power on. Pulled it apart and have a few blown fuse resistors (large gray 0.43 ohm) on the power supply board. New ps ordered for the TV. Ive checked the main board as well as the backlight boards and tconn. None of the boards except the ps show any damage.

Just wondering if anyone has any tips on this. I don't want to cause any more damage to the tv. Im sure my post is pretty vague but im a newb at lcd tv's and am hoping to get this fixed. Normally i would just find a service manual but there doesnt seem to be one for this unit.

Thanks in advance to any posts.

[retiredcaps]

Re: Westinghouse TX-47F430S ps replacement

Normally i would just find a service manual but there doesnt seem to be one for this unit.

Try searching

http://elektrotanya.com

for the model number listed on the power board (not the TV model). Sometimes power boards are used by multiple manufacturers.

[minki12]

Re: Westinghouse TX-47F430S ps replacement

Thanks for your reply,
It is a liteon PA-5421-1-LF supply. I went ahead and opted to just replace the ps board as it was pretty cheap and the control ic didnt look so hot. Im just looking for any suggestions of other things to check before i plug in the new powersupply.

[tom66]

Re: Westinghouse TX-47F430S ps replacement

There is very little a bad main board or inverter or other component can do to damage a power supply - they are short circuit protected and they just won't work (but neither will they be damaged) if something is shorted on the other boards.

[minki12]

Re: Westinghouse TX-47F430S ps replacement

Thank you Tom, I just wasn't certain and didn't want to fry anything else. Much appreciated

[minki12]

Re: Westinghouse TX-47F430S ps replacement

Recieved new ps. I get video for a split second and then lose it. Audio keeps going. Im going under the assumption its the inverter boards. Is there a way to troubleshoot whether its the master or the slave? I tried unplugging them one at a time but no luck as i get no backlight at all. Thanks in advance for any replies.

[minki12]

Re: Westinghouse TX-47F430S ps replacement

Using a flashlight i can see that there is video on the screen just not getting backlight. I assume this means the tconn board is good?

[PlainBill]

Re: Westinghouse TX-47F430S ps replacement

Using a flashlight i can see that there is video on the screen just not getting backlight. I assume this means the tconn board is good?

Correct.

PlainBill

[minki12]

Re: Westinghouse TX-47F430S ps replacement

Thanks to all who responded for the help. found a pin on one of the inverter boards that was bent. fixed her up and shes a running.

[DLinkOZ]

Re: Westinghouse TX-47F430S ps replacement

Any idea what could take out those .43 ohm resistors? I have this same TV with half of them dead. They're in groups of two, and if one is gone then they both are.

[momaka]

Re: Westinghouse TX-47F430S ps replacement

Post some pictures of your power board (front and back as viewed straight down). Have good light in the room when taking the shots. Attach in your post using the "Manage Attachments" button in the "Go Advanced" post editor.

[DLinkOZ]

Re: Westinghouse TX-47F430S ps replacement

I just went ahead and ordered a replacement, they're cheap enough and it arrives tomorrow. But for the sake of any who may come across this thread, I'll post up some pics tomorrow of the old board to see if anything can be of use.

[DLinkOZ]

Re: Westinghouse TX-47F430S ps replacement

Well, new power supply in and it goes into standby, so that's progress. But it won't turn on (neither via remote nor power button). Everything looks good, except for a low 12v:

12v - 11.18v
5v - 5.02v
5vstb - 4.99v
24v - 24.4v
bl_on - 0
pwr_on - 4.8v
v_sel - 0
v_epwm - 3.2v

On the inverters, VBL reads at 25.6v. But still just an amber standby led and no signs of life.

[selldoor]

Re: Westinghouse TX-47F430S ps replacement

BLON doesnt look at all good.May be main board problem .

[elmoslemur]

Re: Westinghouse TX-47F430S ps replacement

Im quite new to this. I had a quick question. I couldn’t get a clear understanding from the how-to-guides i read. The question is in order to power on the power supply to check it do i bring the pwr_on pin to ground (like old computer power supply) or do i need to supply it with 5 volts? Thanks for any assistance.

[momaka]

Re: Westinghouse TX-47F430S ps replacement

The question is in order to power on the power supply to check it do i bring the pwr_on pin to ground (like old computer power supply) or do i need to supply it with 5 volts?

I think all LCD TV power supplies I've seen require you to pull the POWER_ON/PS_ON/PWR pin high to either 3.3V or 5V. There may be some where this may not apply. But either way, you won't harm the TV PSU if you tried both ground and 3.3/5V.

I usually use a 470-4700 Ohm resistor to pull the power-ON pin to 3.3/5V. That way, if I accidentally tried to jumper the wrong pin, the PSU won't get damaged.

By the way, good to see another fellow from Fairfax, VA here.