Sharp lc-42sb45u no response... at all.

[budm]

Re: Sharp lc-42sb45u no response... at all.

That means the transistor of the PS_ON detection circuits on the power supply is getting enough Base current to turn it on, if you discconect that PS_ON from the main board and check the output voltage at the PS_ON pin on the main board, you will more likely to see something close to 5V.
For the backlight to turn on, it should have another signal called "BL_ON", or "INV_ON" from the main board that goes to the Inverter board.

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

So, I have checked some voltages and they all seem fine.
Not sure about the inverter and brightness voltages should be, but they are 3.2V both of them. It shouldn't be one of them higher then the other?
The inverter gets the 24.4V, fuses(2x) are good, but when I measure the VCC and VDD voltages to the two ICs(OZ964GN & BA2902F) I don't think they are getting any. The BA get's at pin #4 0,43V and the OZ gets 0V at pin #5.
Not sure on how to check the FET transistors on this inverter, they are the ones with five pins(4+1) P2204ND5G. The only voltages I'm getting is on the tab or center pin is the 24.4V and on S2 the same 24.4V. The others are 0V.


https://cdn.badcaps-static.com/pdfs/...4eb885fbd4.pdf
Just to refresh on what's going on with this TV, screen seems totally dead, but the green LED is on after the power cable is plugged in. That is normal? It shouldn't go in standby first(red LED)?

[budm]

Re: Sharp lc-42sb45u no response... at all.

I do not know if you have the pictures of this inverter board or not, can you tell me which post they are in? It sounds like you do have BL_ON OK.

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

I haven't taken photos yet. I will take some tomorrow. Do you need just the inverter's picture?
Here is one from shopjimmy until then:
http://www.shopjimmy.com/cmo-27-d026...t-inverter.htm

[budm]

Re: Sharp lc-42sb45u no response... at all.

For now. If I am correct, there is a small black fuse F1 (look like surface mount resistor next to the white fuse F3 on your board) for the Inverter IC. It should be closed to one of the connectors. I am not sure if you see that or not. See picture for example.

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

I see it(FT 20), but that board is different then mine.

[budm]

Re: Sharp lc-42sb45u no response... at all.

The picture I post is just an example of what the fuse looks like. So do have the Black fuse on your board?

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

I will have to check tomorrow, now it's to late.

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

Found it and it's bad. Thank you. It looks like it's a 15A fuse. This fuse is a regular SMD fuse or it is a special one?
Thank you budm!

Side note, I have sold that Sony that I have cracked the screen for $80 (what it cost me too, $50 TV+$25 Tube+$5 gas).
Picture taken with the little Celestron USB microscope, wasn't pointing straitght at it, that's why is not clear at the top.

[budm]

Re: Sharp lc-42sb45u no response... at all.

That is 1.5A fuse. CMO and DARFON use this kind of fuse for the Inverter IC. You can use fusible resistor, 1 Ohm in its place to test it.
Do you have info on this USB Micro scope? It is strange that the board shows it as 0.75A 76V fuse

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

I may have some 1.5A LittleFuse fuses, it should be OK?
http://www.amazon.com/Celestron-Delu.../ref=pd_cp_p_0
The only negative that I can say is that the LEDs are on while the PC is on, but you can use it to make light on the boards.

[budm]

Re: Sharp lc-42sb45u no response... at all.

I use Littlefuse PICO fuse.
Thanks for the link for the scope. I may get one.

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

TV it's working!!! Thank you budm. I owe you a beer.
I can't find that size on Digikey, .125x.060. But I have used one like the other white one, just added some copper wire legs to it.
Bummer is that I can't find that black plastic cover for the inverter.

[budm]

Re: Sharp lc-42sb45u no response... at all.

Great news.

[retiredcaps]

Re: Sharp lc-42sb45u no response... at all.

toddfunn.com has a review of an USB microscope (22 minutes). Direct link is

http://www.youtube.com/watch?v=biTiN...layer_embedded

[budm]

Re: Sharp lc-42sb45u no response... at all.

Thanks retiredcaps, my eyes are not as good as they used to be. I use big micro scope @work for surface mount works, but it will be too big to have one those big scope at home.

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

they are pretty cool tools. I can bring it with me in the bad using the laptop and I can work while I'm resting too. That's how I found the little fuse today, while my daughter was sleeping next to me(the only way she will sleep, soon she will be four).
I don't think that there are big differences between these microscopes. I went with this because it was 2megapixel, had great reviews and wasn't that much money.
I actually looked for a real telescope too, but they are really expensive, triscope, stereo+camera. Maybe a bit later and must be a used one. I really need something because my eyes are not what they used to be. I'm 45, so is kind of expected.
Budm, now I'm ready again to try to fix that Vizio power supply.
I would appreciate your help with this one (too ).
I think that we agreed to go with the one that supplies some voltage at the output.
Do you think that I should recap that power supply?

[budm]

Re: Sharp lc-42sb45u no response... at all.

How many bad one do you have now?

[tibimakai]

Re: Sharp lc-42sb45u no response... at all.

three, but on one I have removed the secondary heat sink, managed to brake some legs off of those diodes mounted to it, but I can add some wires and I can re solder it. I will do it and see how is that one too.

[LastLeg]

Re: Sharp lc-42sb45u no response... at all.

I'm having a similar problem with my Sharp lc-42sb45u. It would come on after a few minutes, or hours, but now has gotten worse. I just opened it up to have a look inside and noticed the capicitor on the bottom right of the power board on this picture:
http://nadams.smugmug.com/Other/Shar...Hv4c&lb=1&s=X2
on mine has opened on top with some yellow-ish residue on it. I suspect this is the culprit that needs replacing but wanted to ask for advice first. The capacitor is labelled CapXon 2700uF16V. Any help would be great. Thanks.