phillips lcd keeps blowing fuse

[selldoor]

Re: phillips lcd keeps blowing fuse

ok I got the screen removed. the bulbs " look " good. if one was bad would that cause this issue? and if so how do i test them?

Yes - one bad could cause them all to cut out.

Not conclusive perhaps rig a couple of Budms test lamps?
https://www.badcaps.net/forum/showthread.php?t=19987

[TimT]

Re: phillips lcd keeps blowing fuse

I put the inverter and t-con back in and attached power. I can confirm the all bulbs do light up. still a quick flash of light

[TimT]

Re: phillips lcd keeps blowing fuse

ok I got the screen removed. the bulbs " look " good. if one was bad would that cause this issue? and if so how do i test them?

[TimT]

Re: phillips lcd keeps blowing fuse

it will be a learning experience for me so I will do this in the morning. I love to tinker! Even when I don't know what I'm doing

[budm]

Re: phillips lcd keeps blowing fuse

That is not good news, sorry to hear that. I do not see what else it can be, since it has all the required voltages and signals. Inspecting the lamp assembly will be the next thing to do. Not sure if it will be worth it at this point.

[TimT]

Re: phillips lcd keeps blowing fuse

install the new inverter board still the same issue

[TimT]

Re: phillips lcd keeps blowing fuse

found one on ebay for $35 shipped! will install and report back thanks for your help!!!

[budm]

Re: phillips lcd keeps blowing fuse

I would try new inverter board at this point if it is cheap enough.

[TimT]

Re: phillips lcd keeps blowing fuse

The Tv does turn off. I was responding to a question someone asked if the TV turned off " on it's own " . the Tv functions correctly menu, volume, channels, ect. turns off and on with power button. everything works except backlight.

[budm]

Re: phillips lcd keeps blowing fuse

Not 100% for sure since bad lamp (one or more may not be on) can also cause shutdown.
Also, you have indicated earlier that you still cannot turn the TV off per post 81, unless I read it wrong.

[TimT]

Re: phillips lcd keeps blowing fuse

budm do you think the problem is on the inverter board? or somewere else?

[budm]

Re: phillips lcd keeps blowing fuse

Well, that eliminate the over current shutdown problem. Need to look some where else next.

[TimT]

Re: phillips lcd keeps blowing fuse

no luck with the jumper

[budm]

Re: phillips lcd keeps blowing fuse

Yes, that is the primary side of the current sensing transformer, the output winding on the right side feeds the Dual Diode to convert AC to DC for the current feedback.

[TimT]

Re: phillips lcd keeps blowing fuse

budm you talking about these two pins?

[budm]

Re: phillips lcd keeps blowing fuse

Did you try jumping those two pin on the left side of the current sensing transformer yet. If it still does not stay when they are jumped then we can eliminate lamp over current as the cause of the problem and look some where else.

[TimT]

Re: phillips lcd keeps blowing fuse

I got a new multimeter today (Klein) so I retested the current senser transformer. when lamps kick in 0175. tested twice. it's Auto Ranging.

[budm]

Re: phillips lcd keeps blowing fuse

This current sensing method is about the same as the SAMSUNG/SONY use on the balancer board. They save money on this one by using only one sensing transformer for all the lamps, not like SONY/SAMSUNG that detects each lamp.

[tom66]

Re: phillips lcd keeps blowing fuse

It's quite possible it's a very short transient causing the controller to shut down, if it's a "dumb" controller.

[budm]

Re: phillips lcd keeps blowing fuse

I expect something like 0.2~0.5v when lamps are on, and more than a volt if the lamps draw too much current.
I am running out of idea, I am thinking about put the jumper on the two terminals on the left side of that current sensing transformer to see if the lamps will stay on, that will tell us if the lamps shutdown due to too much current or not.