Sharp LC-32DH66E green light no power fixed

[tom66]

Got this lovely 1080p 32" Sharp for £29.00 plus fuel. Thought it'd make an interesting project.

Fault description: intermittent refusal to power up. Green LED lit, but set does nothing. No backlight, no image. However, after a lot of playing with on/off buttons, the set will power on and then works great.

The particular fault is identified in Sharp service bulletin "LCD 2010 07 05".

The 3.3VD line measures just 2.35V. The LED on the main board blinks continuously and the set does not power up. Upon freeze spraying suspect area, the 3.3VD rose to the correct level, and the set powered up and worked perfectly. Therefore, I will replace the indicated capacitor.

I am keeping this for the bedroom.

[budm]

Re: Sharp LC-32DH66E green light no power fixed

Might be a good idea to replace the other cap on pin 6 which is the same value as that bad cap ( extreme drifting in value with temp?).

[tom66]

Re: Sharp LC-32DH66E green light no power fixed

There's three other converters of the same design. I think I'll replace all three 6.8nF capacitors.

I think it's the same thing as 10 blink Panasonic failure. The capacitor becomes leaky, but not shorted. Hence the SS voltage can't reach the full amount. Once the capacitor cools down, somehow it stops becoming leaky and set works.

Question: Why does only this capacitor become leaky? Thwo other converters, for 1.8V and 5V, also exist with same design but there are no bulletins for them. Points to perhaps some design change not reflected in schematic? Or perhaps different temperatures in that area?

This set is so well built. Huge heatsinks on power supply and lovely Sharp LCD panel too.

[martino]

Re: Sharp LC-32DH66E green light no power fixed

I am keeping this for the bedroom.

Lol,the glory of fixing TV's ,we got a 52" plasma in our bedroom now

[tom66]

Re: Sharp LC-32DH66E green light no power fixed

52" plasma? Do you mean 52" LCD or 50" plasma? Nobody makes a 52" plasma.
I was on the look out for a good bedroom TV, the current 42" Panasonic fullHD is far too big for me to keep anywhere sensible. This 32" can possibly be wall mounted or put on a book case/small table.

[budm]

Re: Sharp LC-32DH66E green light no power fixed

If you can test the capacitance and leakage resistance with heat and cooling, it may give you a hint to what is bad about this cap. Is it ceramic disk X7R, 5Y, etc. or MLCC? I alos wonder what that SS pin on the IC is for.

[tom66]

Re: Sharp LC-32DH66E green light no power fixed

I'll see if I can do that. Will be interesting.

[martino]

Re: Sharp LC-32DH66E green light no power fixed

52" plasma? Do you mean 52" LCD or 50" plasma? Nobody makes a 52" plasma.

50" plasma,you are totally correct

[tom66]

Re: Sharp LC-32DH66E green light no power fixed

Diagnosis video
http://www.youtube.com/watch?v=a-Pux...ature=youtu.be

Repair video coming soon...

[tom66]

Re: Sharp LC-32DH66E green light no power fixed

Forgot to say this got fixed a few days ago, just replaced capacitor on main board, fired up immediately no problems.
Lost the original 0402 capacitor unfortunately :/ so can't test it.
It looks great! Awesome picture, but PenTile 1080p matrix screen (cheaper), not great for text up close. Fine at distance though.