Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

[DXseekerMO]

Earlier this week I got an Emerson LF501EM5F that turns on, the logo comes up, a menu and the channel box come on and it immediately shuts down a split second later.

This was bought new and went in a Laundromat. From there it was on from 7AM to 10PM every day.

So why is this the perfect storm? A month ago I got an Emerson LF501EM4 and an EM4A, both will not turn on. The EM4A was struck by lightning and has a serial of DS1 The EM5F has a serial of DS5. The EM4 has a DS4 serial and the chirping transformer problem with a replaced power supply.

The info I have is the 4A DS5 and 5F DS1 share the same internal components. On top of that all three sets have the same part number for the display.

The plan is to diagnose according to this thread unless suggested otherwise:

https://www.badcaps.net/forum/showth...ight=lf501em5f

I'm going to start on this today since we have cold and snow, plus I'm waiting on a sun load sensor for this Nissan Titan I'm working on. Snow, in southern Missouri in April? Hope you all are ready for the coming ice age!

[DXseekerMO]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

First....board pix

[DXseekerMO]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

Ok here's what I am seeing:

STBY_3.3..........3.31 steady, 0V boards unhooked
P-ON+21V.........14.40 steady, 13.8 steady boards unhooked
AMP+13V..........7.95 steady, 8.14 steady, boards unhooked

CN001 (to LED strings)

Red..............80V decreases to 55V/ 80V, decreases to 55V PSU disconnected
Yel...............23v, decreases to 1.5/ 0V disconnected
Blu..............79.3 stays within 10%/ 80 decreases to 55 disconnected
Gry.............6.2V, decreases to .7V, increases to 6.2V/ 0V disconnected
Blk..............78.2V, decrease in lamp intensity, increases to 78.6V/ 55V, jumps to 80V, decreases to 56V disconnected
Wht.............13.8V, decreases to .7v, decrease in lamp intensity, increases to 7.5V/ 0V disconnected.

Capacitor C1305 rating: 100uF, 100V, not popped.

Based on that thread, the voltages seen and required at P-ON+21V and AMP+13V and the voltage values at CN001 I'm thinking bad LED's and something bad on the power board? My guess is when the LED's went something on the PSU may have also been damaged?

[DXseekerMO]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

And here we go!

[budm]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

STBY_3.3..........3.31 steady, 0V boards unhooked
P-ON+21V.........14.40 steady, 13.8 steady boards unhooked
AMP+13V..........7.95 steady, 8.14 steady, boards unhooked

So with all the boards are connected back in place, what DC V do you get at P-ON+21V and at AMP+13V when power switch is activated?

[DXseekerMO]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

Budm, I failed to perform that test.

Here's what I did:

I took the EM4A which had low hours and reported to work good (before a chirping power supply problem) and installed the EM5F PSU and main board into that. It turned on and it's now working in my living room.

Just for knowledge are the voltages supposed to increase to those specs with power on?

The way I saw it why take a chance on busting a good display when I already have one with good LED's and interchangeable boards?

[budm]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

P-ON+21V.........14.40 steady, 13.8 steady boards unhooked
AMP+13V..........7.95 steady, 8.14 steady, boards unhooked

Those two Voltages are at the standby mode, when PS-ON is present then they will go up to the printed rated Voltage.

[DXseekerMO]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

Right on. That thread was very very handy and I got enough out of it not to have to ask so many questions. It's board changing, but it's a start!

Thanks for that thread budm and for your help.

[DXseekerMO]

Re: Emerson LF501EM5F, turns on, logo appears, shuts off, the perfect storm?

Just wanted to close this thread out. I just sold this TV aboot an hour ago. It worked flawlessly in my living room since my last entry.