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Old 06-12-2012, 05:23 PM   #1
shorteddiode
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Default Emerson LC401EM2F

TV was off during a lighting storm but wouldn't turn on after the storm was over. I opened up and to my suprise no dark spots and so far all I have found is a bad diode. Number D1215, but has no markings, it is in the power supply and is glass. Anyone have an idea what the replacement would be, or the location of a schematic? I can never seem to find the schematics I need
I treid Elektro Tanya with no luck, any other good schematic sources?
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Old 06-12-2012, 05:26 PM   #2
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Default Re: Emerson LC401EM2F

Can you post a picture of where the diode is used - we may be able to guestimate the replacement type.
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Old 06-12-2012, 05:41 PM   #3
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Default Re: Emerson LC401EM2F

Pictures will help. Main fuse did not blow? I expect the TVS devices to kick in and blow the main fuse.
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Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

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Old 06-12-2012, 05:46 PM   #4
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Default Re: Emerson LC401EM2F

No fuse on the TV is good, I'll get pics and post them
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Old 06-12-2012, 05:54 PM   #5
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Default Re: Emerson LC401EM2F

The first pic shows the diode
the other two just show the power supply board
Hope this helps
Attached Images
File Type: jpg 001.jpg (163.6 KB, 119 views)
File Type: jpg 002.jpg (287.4 KB, 98 views)
File Type: jpg 003.jpg (304.1 KB, 82 views)
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Old 06-12-2012, 06:09 PM   #6
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Default Re: Emerson LC401EM2F

Can we see the back side of the board so we can try to trace out the connections and figure out the function of that diode.
Right now do you get any voltage on that large DC filter cap?
By the way, is that big blue rectangular case next to the Diode a relay? Otherwise that may be the snubber Diode for the relay coil which are hooked up in parallel, then the Diode will read both way due to the relay coil is in parallel with the Diode.

Last edited by budm; 06-12-2012 at 06:11 PM..
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Old 06-12-2012, 06:13 PM   #7
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Default Re: Emerson LC401EM2F

I'll get pics of the back in the AM, I havent run voltage yet since the diode is bad and the set will not turn on
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Old 06-12-2012, 06:15 PM   #8
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Default Re: Emerson LC401EM2F

I edit my post6 so please read more questions I added.
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Old 06-12-2012, 08:55 PM   #9
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Default Re: Emerson LC401EM2F

I get no reading on that diode, I'll lift a leg and try it
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Old 06-12-2012, 08:59 PM   #10
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Default Re: Emerson LC401EM2F

I will wait for the bottom side pictures of the board.
So is that blue component a relay?
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Old 06-13-2012, 03:40 AM   #11
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Default Re: Emerson LC401EM2F

Pictures will need to be a lot sharper for troubleshooting - they should look like this - try outside in daylight.


Examples of what is needed
http://www.badcaps.net/forum/attachm...1&d=1290283049

http://www.badcaps.net/forum/attachm...7&d=1280167246
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Old 06-13-2012, 05:37 AM   #12
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Default Re: Emerson LC401EM2F

I have been doing a bit of research on this- The blue box is a relay - see pic of another board.
Moving on it seems to be the same chassis as a Philips 40PFL3705DF7 chassis no PL10.5
The SM is here:
http://elektrotanya.com/philips_40pf.../download.html
From that the diode is a 1N4148-F0021 ( Datasheet attached)which oddly enough used to be stocked by Sears as a spare part- the page comes up then says not found!! perhaps they still have them?
Anyway it stays on long enough to see it is a vishay 1N4148 - lots to choose from at digikey
I bet after all that the diode tests good.
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Old 06-13-2012, 07:46 AM   #13
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Default Re: Emerson LC401EM2F

sorry ignore wrong post
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Old 06-13-2012, 11:31 AM   #14
shorteddiode
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Default Re: Emerson LC401EM2F

Here are pics of the bottom of the board. The two black lines indicate the leads for the diode.
I did some voltage tests and I have 79 volts AC accross the diode on both sides of it. No power to the inverter from the power supply board. I have two 5 volt and one 3 volt dc to the main board from the power supply. The set will not turn on and you do not hear any clicks whe the power button is pushed. I forgot to look for a standby light.

Thanks selldoor for the diode info
Attached Images
File Type: jpg 001.jpg (307.0 KB, 58 views)
File Type: jpg 002.jpg (334.7 KB, 50 views)
File Type: jpg 005.jpg (167.2 KB, 41 views)
File Type: jpg 006.jpg (464.4 KB, 46 views)
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Old 06-14-2012, 05:20 PM   #15
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Default Re: Emerson LC401EM2F

Gaining some ground. The diode was bad, and since I replaced it the TV will click when plugged in but won't turn on. I do not have a standby light but I have 5 volts for standby voltage on the IR board.
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Old 06-14-2012, 06:06 PM   #16
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Default Re: Emerson LC401EM2F

This chassis looks like it was built by an "engineer" (hah!) trying to save every last penny - it looks awful. You get good 5V, any PSON signal from main board? If so, any main outputs? How is the relay driven?
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Old 06-14-2012, 07:08 PM   #17
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Default Re: Emerson LC401EM2F

The Diode is in series with the relay coil.
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Old 07-09-2012, 01:57 PM   #18
shorteddiode
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Default Re: Emerson LC401EM2F

OK I now have the TV with a standby light, But it will not turn on. When I plug it in the stand by light flashes 16 times then stops. When I oress the power button I get 14 flashes and then it stops unless I press the power button again. I can't find the codes, anyone have acess to them?
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Old 07-09-2012, 02:03 PM   #19
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Default Re: Emerson LC401EM2F

Not sure if this service manual is close to what you have or not.
http://elektrotanya.com/?q=showresul...oria=&kat2=all
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Old 02-15-2013, 10:26 AM   #20
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Default Re: Emerson LC401EM2F

Alright so im new to this whole forum thing so i dont know how to post a new thread so i guess ill just post on here to see if i can get some help.
well this tv i have here (emerson LC401em2f) whenever you plug it in and try to turn it on a red light starts flashing then stays a steady red after a few blinks. The screen doesnt come on and the fuse is fine. I dont have a schematic for the tv and i dont have any software to open any of the adobe files or pdf files on my computer. Thats all i can tell anyone.
My apoligies to the person who started this thread i just cant figure out how to start a new thread since im new to this.
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