Emerson LF391EM4F blinking red nothing else

[GregWmson]

Red light constantly blinks on set. Nothing else. No pic, no pops, clicks or sounds. No codes that i can tell, I stopped counting at 20 flashes.

Replaced Power board with one from shop jimmy. No change.

Any Suggestions on what to check next?
Ive got a cheapo harbor freight mulitmeter. like this.. https://www.youtube.com/watch?v=5WrtQ6i6fuo But honestly not real comfortable with it, so please tell me what settings to use on the Meter when checking components.
thank you guys for any help you can offer.

[budm]

Re: Emerson LF391EM4F blinking red nothing else

Please start with this:
https://www.badcaps.net/forum/showthread.php?t=39740

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

Images attached.

[budm]

Re: Emerson LF391EM4F blinking red nothing else

The pictures of the whole back side of the TV too please so we can see how all the boards are connected together.

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

Ok, here ya go. Thank you.
I found a main board for <$30 on ebay, I went ahead and pulled the trigger.

[budm]

Re: Emerson LF391EM4F blinking red nothing else

So it only has one power transformer to supply the Voltages to all the boards.
Since you are getting the blinking RED light that means the power supply is running but we do not know if the Voltages are fluctuating so it makes the light blink or there is problem in the power supply or in the main board.
We will need to test the Voltages at the connector on the power supply that goes to the main board.
http://www.shopjimmy.com/catalogsear...rson+LF391EM4F
I would start checking the DCV on those jumper wires (close to the black connector) which have the labels for them to tell you what the Voltages should be and also the control signal names.
Also check ALL the diodes in the secondary side of the circuit.

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

Thank you for your help BudM.

I had already replaced the Power Board with one from shop jimmy and noticed no change so I removed it and put the old one back on and ordered a new main board from ebay yesterday. should be here in 3-4 days. Do you think that is going to probably fix my ailments?

Are you talking about connection 501? where the ribbon cable plugs into on the power board? I don't see any test points on that connector. I do see on J79 AMP 13v and below it, J80 Pon21v

Is that where I should check?

How do I go about checking the control signal names? Which ones should I be looking for. what settings should I put my mulitmeter on and what should they be reading. Do I just ground my black lead on a screw or something and touch them with the red lead? Sorry for the newb questions just don't want to mess up anything.

[budm]

Re: Emerson LF391EM4F blinking red nothing else

"Are you talking about connection 501? where the ribbon cable plugs into on the power board? I don't see any test points on that connector. I do see on J79 AMP 13v and below it, J80 Pon21v

Is that where I should check" Yes, you got it, FUNAI is too cheap to put the label for each pin of the connector to make it easier to test the board.
I wonder if do you have main board problem since SJ sells the repair kit for the main board.

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

J79 reads 12.8 v

j80 read 22.8v

[budm]

Re: Emerson LF391EM4F blinking red nothing else

So the test points are:
J141: BL-ADJ
J153: PROTECT3
J156: BL-SW
J81: LED -CONT
J79: AMP+13V
J80: P-ON+21V
J85: P-ON H2
J86 :3.3V
So none of the Voltages on the jumpers are going ON and OFF? If that is the case then more likely you have main board problem not the unstable power supply problem.

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

Bud, Not sure how to test all of these what values should I be looking for with these? The ones that are marked with a value I have checked and they appear to be within range. +-5%

J141: BL-ADJ
J153: PROTECT3
J156: BL-SW
J81: LED -CONT
J79: AMP+13V Tested 12.8v
J80: P-ON+21V Tested 22.8v
J85: P-ON H2
J86 :3.3V Tested 3.5 V

How do I check the other? I have put my lead on them and I am getting values. like .2 and .4 but nothing significant. Sorry for my ignorance, but this is my first crack at this and I really do appreciate your patience and assistance.

[budm]

Re: Emerson LF391EM4F blinking red nothing else

Just set the meter to DCV and take the readings. We just want to see what you have so we will know if some of the Voltages or signals are missing or not, if it shows 0V or what ever then just report them as what are shown on your meter.
So far it does not look like you have fluctuating power supply outputs.

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

Here you go.

J141: BL-ADJ .2
J153: PROTECT3 .4
J156: BL-SW .2
J81: LED -CONT 0.0
J79: AMP+13V Tested 12.8v
J80: P-ON+21V Tested 22.8v
J85: P-ON H2 2.0v
J86 :3.3V Tested 3.5 V

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

Are these results within spec?

[budm]

Re: Emerson LF391EM4F blinking red nothing else

The PS-ON is fine (2.0V), the 13V is fine.
But the main board is not sending B-SW (BL-ON), BL-ADJ, which makes sense because you have blinking LED lights right now.
The PROTECT3 = 0.4V I am not sure if that is normal or not.
I do suspect that you have main board problem.

[GregWmson]

Re: Emerson LF391EM4F blinking red nothing else

thanks budm, wanted to give you a followup and let you know it was the main board, got it in today, and got it working. Thank you very much!!

I just told my neighbor and he sent me home with a westinghouse tv SK-32H750D that he gave me.

It has no lights, no power, no anything. He says he "thinks" it was struck by lightning but not sure. I pulled the cover off and was looking for signs of gross voltage overload and it looked fine, no blown or swollen capacitors, brown spots or charred components of any type. A cursory look on the net seemed to say there was a problem with the caps on this unit on the Power board but they all looked normal to me.

my readings are from the power board to the inverter is "from right to left"
13.45
13.45
.02
.02
5.49
5.49
5.49
5.51
.03
.02
4.98
.01
3.16