Emerson lc220em2 blows fuse

[Herbssat]

Hi guys. I currently have one of these sets that was blowing the fuse. Replaced Q601 and Q602 as well as 2 zener diodes and set still wouldnt turn on. Traced it back to a shorted component in the secondary(D631 smd) and noticed this diode has high voltage and current capability. I would like to know what probably caused this and what can be done to keep this set running. No need to waste time repairing it to go down in other 6 months. Suggestions on modifying this board are appreciated.

[ecking767]

Re: Emerson lc220em2 blows fuse

service manual

[Caleb]

Re: Emerson lc220em2 blows fuse

This failure scenario seems to be common a diode in the secondary shorts then the primary drives current into the short until it fails as well. Not sure if the diodes they use are underrated or just poor quality, I usually replace them with a higher rated version. The most common diode I have seen fail is a 2 amp (100v I think) I usually replace it with a 3 amp 200v schottky.

[Herbssat]

Re: Emerson lc220em2 blows fuse

Thanks Caleb. Everybody talks about those funai power boards being poor quality. I already ordered a 2 amp from mouser but i will try that on the next one. A big box store that we all know has a 40 inch advertised on black friday for a little over $100. I am quite sure the phone will be ringing off the hook 6 months later. Lol.

[Caleb]

Re: Emerson lc220em2 blows fuse

I fixed one last spring that lasted only 3 months, not sure why they didn't take it back for warranty repair. But yes I am looking forward to a good storm this winter that will bring a myriad of flatscreens into the recycle yard.

[Shane711]

Re: Emerson lc220em2 blows fuse

I need help, I have this Emerson lc220em2. I opened it up and there was a blown fuse but the transistor at Q601 is missing. Does anyone know what the part number is for Q601? I tried putting a common one in but doesn't seem to be working.

[dick_barton]

Re: Emerson lc220em2 blows fuse

Q601 given in the manual above in post #2 is a Mosfet 2SK3561

[budm]

Re: Emerson lc220em2 blows fuse

Service manual.
TK7A50D ISO-TAB
http://www.mouser.com/ProductDetail/...mjQB4Kqg%3D%3D

[Shane711]

Re: Emerson lc220em2 blows fuse

That manual in post #2 does not have my board. It has boards for LC220EM1 and my TV is a LC220EM2.

[Shane711]

Re: Emerson lc220em2 blows fuse

Thanks budm, that is the Service manual I need. Busy looking it over now.

[budm]

Re: Emerson lc220em2 blows fuse

Make sure to check ALL the diodes on that board, the inverter MOSFETs, and the Transistors in the primary side.
Lots of parts in the primary side get wiped out when the secondary side has shorted circuit.

[dick_barton]

Re: Emerson lc220em2 blows fuse

My error. Sorry.

[Shane711]

Re: Emerson lc220em2 blows fuse

OK, so it looks like TK7A50D is the part number. That is not what I put in that spot. I will have to order some. Thanks a lot. I replaced some of the other parts already. but Q601 was missing entirely. I just checked over the board again and I think I got everything. Now I just have to wait for Q601 to be delivered.

Thank you.

[RideNFly13]

Re: Emerson lc220em2 blows fuse

Make sure to check ALL the diodes on that board, the inverter MOSFETs, and the Transistors in the primary side.
Lots of parts in the primary side get wiped out when the secondary side has shorted circuit.

Forgive me for not knowing but, I'm pretty new to the game. Which is the primary side and which is the secondary? Also, where do I go about buying the diodes to replace the bad ones? Is there a generic version of the zener diode or does it need to be an exact replacement? Is there somewhere I can learn this stuff? Thanks.

[nomoresonys]

Re: Emerson lc220em2 blows fuse

Video there, be sure to respect the PRIMARY/HOT side it can KILL: https://www.youtube.com/watch?v=M2v04tdp5B8

[RideNFly13]

Re: Emerson lc220em2 blows fuse

Video there, be sure to respect the PRIMARY/HOT side it can KILL: https://www.youtube.com/watch?v=M2v04tdp5B8

Thanks for the video! I'm slightly less likely to kill myself now!

[budm]

Re: Emerson lc220em2 blows fuse

At least plug what ever you are testing into GFCI ac outlet to protect yourself.