phillips lcd keeps blowing fuse

[MisterD]

Re: phillips lcd keeps blowing fuse

I think that bl sw could be the same as bl_on which is at 3v and it seems like that would cause the inverter to fire up the backlights..can you hook your volt meter to this pin again and monitor the voltage? see what the voltage is when you first power on the TV, then leave the meter probe in place and see if this voltage stays constant, report your readings back here.

Hopefully budm and tom66 can help with this one. See Post#77, he has replaced the Power Supply Board.

[TimT]

Re: phillips lcd keeps blowing fuse

Sorry, you are correct bl sw 3v

[MisterD]

Re: phillips lcd keeps blowing fuse

Here are the readings from the mainboard connector and inverter connector.

main

tuner 35v is getting 39v
lcd 12
lcd 12
p+on 3.36v
+6.5vf or 1v gets 11v
p-on 3.5v or reg gets 6.70
p+ on 5v
24v for amp gets 27.8

inverter

power sel 0
bl adj is not used
bl 5w gets 3w
error 0
gnd
gnd
gnd
gnd
gnd
24v
24v
24v
24v
24v

not sure how to inturpet these results?
there is a 10amp SMF on inverter and it's getting 9.6 on both ends. inverter lights up for a split second thats when i see the " phillips " when inverter goes out the phillips is still there. then I see the no signal. this is extremely hard to see! I can ajust the sound/channels ect it works fine. menu works fine. powers off and on correctly. seems everything works fine just no backlight.

Default Re: phillips lcd keeps blowing fuse
Here are the readings from the mainboard connector and inverter connector.

main

tuner 35v is getting 39v
lcd 12
lcd 12
p+on 3.36v
+6.5vf or 1v gets 11v
p-on 3.5v or reg gets 6.70
p+ on 5v
24v for amp gets 27.8

inverter

power sel 0
bl adj is not used
bl 5w gets 3w ? Is this possibly bl SW getting 3V ?
error 0
gnd
gnd
gnd
gnd
gnd
24v
24v
24v
24v
24v

[TimT]

Re: phillips lcd keeps blowing fuse

Here are the readings from the mainboard connector and inverter connector.

main

tuner 35v is getting 39v
lcd 12
lcd 12
p+on 3.36v
+6.5vf or 1v gets 11v
p-on 3.5v or reg gets 6.70
p+ on 5v
24v for amp gets 27.8

inverter

power sel 0
bl adj is not used
bl 5w gets 3w
error 0
gnd
gnd
gnd
gnd
gnd
24v
24v
24v
24v
24v

not sure how to inturpet these results?
there is a 10amp SMF on inverter and it's getting 9.6 on both ends. inverter lights up for a split second thats when i see the " phillips " when inverter goes out the phillips is still there. then I see the no signal. this is extremely hard to see! I can ajust the sound/channels ect it works fine. menu works fine. powers off and on correctly. seems everything works fine just no backlight.

[TimT]

Re: phillips lcd keeps blowing fuse

I wii test this tomorrow. thank you

[MisterD]

Re: phillips lcd keeps blowing fuse

I found a picture of a power supply board that is used for your Model TV, on the white connector I see a pin labeled BL-3V, the best way I found is to take a safety pin and shove it into that part of the connector to make contact with the 3V connection, then you need to take a reading with your meter set to DC Volts, hook the black prob to the chassis for ground and then touch the red prob to the safety pin connection to the BL_3V Pin and see what voltage reading you get, it should be near 3 Volts.

[MisterD]

Re: phillips lcd keeps blowing fuse

I just fixed a 47" Philips that was doing something similar, It would not shut off, the remote control did nothing, the backlights would come on for an instant then right back off, my problem was the Mainboard was not sending the signal to the Power Supply, replacing the Main Board also known as the Small Signal Board fixed my problem, there may be a way for you to make the backlights come on with an external 3v source, do you see a marking on the power supply board next to the white connector labeled BL_ON ?

[TimT]

Re: phillips lcd keeps blowing fuse

No backlight! The " phillips " is on screen for about 3 seconds. but for the first half second its bright. i can still see it and the menu using a flash light at a angle... that's how hard it is to see it!

[MisterD]

Re: phillips lcd keeps blowing fuse

I assume you have the back off the TV and can't you see the backlight lit up? usually seen through the holes or slots in the metal chassis.

[TimT]

Re: phillips lcd keeps blowing fuse

the tv does not turn off. I can barely see the menu. ajusted brightness up..no change.

[MisterD]

Re: phillips lcd keeps blowing fuse

Is the TV Shutting off right after you turn it on? You say you can see Menus and Controls work but no backlight, without a backlight you would not be able to see the Menu and Controls on the screen, you may have the input set for AV or a setting that is causing a dark screen, especially if the brightness and contrast are set low. if you can see the controls/settings try turning up the contrast and brightness and set input for whatever you are using.. set to TV for Cable TV or set to the correct AV or HDMI depending on what you have hooked up to get a picture and sound.

[TimT]

Re: phillips lcd keeps blowing fuse

it may have had this problem..i dont know

[Dgtech]

Re: phillips lcd keeps blowing fuse

It went from blowing fuses to this? You might have gotten a bad board. Just think if you put that money into getting a better meter, you could have probably fixed your old board by now. Send the new one back. It's giving you new symptoms that the old one didn't give you unless it always had two problems.

[TimT]

Re: phillips lcd keeps blowing fuse

installed the new power board! now the TV powers up then in a few seconds I see " phillips " flash on the screen for less then a second then go out. its a bright flash. then nothing black light is out. I can see the the menu & controls work. but no back light. all fuses test good. any suggestions

[TimT]

Re: phillips lcd keeps blowing fuse

hopefully if Santa is good to me I will get one :-). thanks everyone for your help! I will just keep an eye out for another power board. I'm ready to move on to the next TV

[Dgtech]

Re: phillips lcd keeps blowing fuse

If you ever wanted to fix anything, you need to get a standard fluke meter and read how to use one.

[TimT]

Re: phillips lcd keeps blowing fuse

the readings on the 0.1 uf 250v tested at 20m was in fact 1.00
now with probes disconnected I get 1 there is a decimal like 1 .

[tom66]

Re: phillips lcd keeps blowing fuse

Those readngs sound good except "1.00"?

Do you mean "1 . "?

A "1 . " reading does not mean 1.0, 1.00 or anything like that -- it indicates overrange (>200.) It may be confusing, I have no idea why it is like this...

[TimT]

Re: phillips lcd keeps blowing fuse

touching the probes together I get 00.1
disconnecting probes I get 1
testing the capacitor I get 1 I tested it on every setting
tested the new 0.1 uf 250v at 20m seems to level out at 1.00 though that reading fluctuates

[tom66]

Re: phillips lcd keeps blowing fuse

It's EXTREMELY rare for those caps to fail short circuit. They are safety rated and are not supposed to create a hazardous condition such as that.

Even if one failed, it would be much more rare for all of them to fail.

Sorry, I think you are testing them wrong.

Let's just check this:
- Meter on 200 ohms (horseshoe)
- Touch probes together, tell us the reading
- Disconnect probes, tell us reading
- Touch probes on capacitor, tell us reading