Hisense - 50N4(Backlights on 12v is 2v)

[Amraks]

Brand: Hisense
Model: 50N4
PSU: rsag7.820.5687
mainboard: rsag7.820.6526

Symptoms:
Backlight is on no picture.
Front LED flashes 6 times
12v line is reading 2v
the rest of the voltages are fine.

Filter cap voltage is 379 - 380v

Checked over diodes so far.

Not sure where to go on this one.

[Amraks]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Some photos of mainboard

[dick_barton]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Are you certain the 12V supply is low.
The backlight IC (N901) is supplied by 12V_VCC which is derived from V806 fed from the 12V supply? So if the backlight is operating then I believe that the 12V supply must be working.

It may be a problem with a connection between power supply power lines going to the mainboard. Possible solder joint at one end.

[Amraks]

Re: Hisense - 50N4(Backlights on 12v is 2v)

could there be a short on the main board putting it into protect mode?
I did notice the 16v is only 12v

also notice two caps on the mainboard are short


c1062 c1063

[Amraks]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Well I took the shorted cap from the mainboard out of circuit and we have a picture now tv works should I replace this cap?

Also the chip is
2m = 3d 71f

[Amraks]

Re: Hisense - 50N4(Backlights on 12v is 2v)

I just replaced the cap with 50v ceramic tv works

[dick_barton]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Good repair. Another one saved from the rubbish dump.

[budm]

Re: Hisense - 50N4(Backlights on 12v is 2v)

God job indeed.

[Amraks]

Re: Hisense - 50N4(Backlights on 12v is 2v)

couldn't get a datasheet for that chip but I believe that line is supplying 30vs to that chip.
just a lucky repair which paid off.
hope this thread helps if someone has the same issues.

[hasini]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Thanks for sharing that :-).

Tested same 2 capacitors on my Hisense 50N4 which were both shorted.

Removed C1063 and got video on the screen again :-)

Thanks so much.

[Mrzoop]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Amraks, thank you for posting this. Great find!!

Just like you and Hasani noted, I also had a short on C1063. I have removed the capacitor and have corrected the problem. Video is back on as normal on my 55N4.

One question I must ask, should a new capacitor be installed? What are the risks of leaving it removed?

Thanks again, appreciate your assistance.

Hisense HA55K3140WT/213693/E170303 RSAG7.820.6526/ROH

[trink80]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Hi Guys,

i've got the same problem with my 55N4, can you please tell me the exact replacement capacitor, I'm a novice.

Cheers

Joe

[Mrzoop]

Re: Hisense - 50N4(Backlights on 12v is 2v)

Well I took the shorted cap from the mainboard out of circuit and we have a picture now tv works should I replace this cap?

Also the chip is
2m = 3d 71f

If you have a short on C1063, then simply remove it.

I asked the same question if it needs to be replaced and it hasn't been answered yet..... but my TV is working without it. To get you back on, just remove it.