Sharp LC-60LE633U 2-5 flash

[budm]

Re: Sharp LC-60LE633U 2-5 flash

Is this your T-CON board?
http://www.shopjimmy.com/sharp-duntk...-con-board.htm

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

Is this your T-CON board?
http://www.shopjimmy.com/sharp-duntk...-con-board.htm

Yes and I have access to 48/5801 tst points as well as CN5101 & 7001 without removing the metal brace for the stand.

I haven't yet checked them, or even where they go but will probably start poking around tonight.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

I checked the voltages with tconn ribbon off.
Attached photo with markings. Hope its ok to use the stock picture.

[freakaftr8]

Re: Sharp LC-60LE633U 2-5 flash

Check output voltages of positive side of capacitors C4829 C4863 and C6263. The positive side is the opposite of the purple spot. And do these voltages dissappear when panel is connected to the tcon When the TV stays on without shutting down

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

freakaftr8,
I checked them all and they were good. All shutdown after the error.
1.x, 3.3, 12V is what I found.


So back on this puppy tonight...
Those 2.9-3.0 Voltages got some investigation.
I traced them to a winbond 25X20BVNIG
Data sheet here:


I traced the sporadic voltage to pin 1.
Pin 8 has solid 3.3V
Datasheet says pin 1 is the chip select pin and it says that CS must track VCC at power up.
I lifted pin 1 and measured the voltage at the pad - its solid 3.3.
It is my belief that this component is internally pulling down that 3.3V
I measured pin 1 to 4 resistance but I don't have anything to compare against.

The part I not clear about, is this a pre-programmed component or is is a volatile component?

[freakaftr8]

Re: Sharp LC-60LE633U 2-5 flash

Interesting. Is it doing that with the panel disconnected also?

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

Interesting. Is it doing that with the panel disconnected also?

Yes, it does that regardless of panel connected or not.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

I took this from another angle this morning...attempted to find why it's throwing 12V error.
There is a feedback loop to the uC on the main board- that supplies DET_PNL_12V_CPU signal. This signal is always 0V (jumpstarted or regular power up)
This signal is fed from the tconn signal cable, but I don't have any schematic for the tcon.
The ones I found are for the main board only.

So at this time I believe I have 2 hard evidence pointers to the tcon.
Would love to know if that winbond is use in a volatile manner. If so I could take a shot at replacing it.

[freakaftr8]

Re: Sharp LC-60LE633U 2-5 flash

That windbond is the serial ram flash memory for the processor. It's preprogrammed. If it fails the tcon will have issues. If its cheap enough I'd try another tcon.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

So just to update this thread, I purchased a tcon for $20 on ebay guaranteed to work or your money back.
Well I installed it and had the same symptoms, including that 3.3V being dragged down- so my working assumption is that might be normal. Might not need to be actually 3.3....

I went back to probing the DET_PNL_12V_CPU signal that is supposed to come to the main board. This time I was seeing something in the 2.xx V range.
Better than 0 but not right.

So then I started using some freeze spray, and magically no more blinky light- but still no picture.
Long story short, I ended up focusing on the ribbon that connects tcon to cpu. I noted that the CPU end was not very secure where the cable end is assembled. ( the actual clip into the mainboard is rock solid)

Depending on how I wiggled it I could trigger the blinky light or not.
Added some backing to the cable using aluminum tape and re-assembled, now no more blinky lights, but still no display on screen- but at least the TV starts up in normal mode without any blinky lights but still doesn't show a picture.

My next step is going to get a new cable, who knows what other signals are flaky there.

Interestingly, there is an led on the mainboard that I never noticed before.
It now comes on solid at power up and after backlights turn on, it moves to a steady blinking state. its called CPU_LED.

Anyone know what that signifies?

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

Now that its dark out I was able to confirm the following:
1. Panel works perfectly
2. Tcon to cpu cable seems ok with my bandaid.
3. Backlight not fully functioning.
4. I see backlight coming out the back but I don't see it on every hole.
5. Playing test patterns reveal some sort of flickering in the back lighting.
6. Overall the screen can only be seen in the dark so it seems led's are not bright or a whole strip or two might not be functioning.
7. My original tcon is just fine.
8. Main issues appeared to have been cable, and backlight.
9. Entire menu works, even internet. I fully believe main board is fine as well.

Is 75V the correct voltage that each strip should be seeing on sharps?

[freakaftr8]

Re: Sharp LC-60LE633U 2-5 flash

Ok so we now have conformation that your mainboard cable to tcon was a bad connection. Check led wiring from power supply for bad connection

[budm]

Re: Sharp LC-60LE633U 2-5 flash

Please report the DCV reading of each L+ and L- of the LED connector.
Delta DPS-165HP-3A.
http://www.shopjimmy.com/sharp-runtk...pply-unit.htm#
Pictures provided by shopjimmy.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

Its 75V that's what I'm getting at.

Also I guess for anyone reading

I see backlight coming out the back but I don't see it on every hole.

should be deleted, since its not possible to see it on every hole as they are blocked by the panel stiffener bar.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

+ to - leg is 75V for each pair at the PSU connector and at the actual strip

I pulled the panel again to ensure the leds are not dead and did full inspection.
All are lit.
However I feel they are rather dim, hence why I'm curious what the V should be.
There are 60 leds per strip. That's 1.25V average available per led, but the vdrop on the first few I checked was around 2.5V.


Oh and also I cranked the backlight to +16 in the menu for testing purposes.

[freakaftr8]

Re: Sharp LC-60LE633U 2-5 flash

To prevent mass confusion, I think it would be best if you take a picture right now of what you see on the screen to help us better identify your issue Something sounds add and I'm confused.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

To prevent mass confusion, I think it would be best if you take a picture right now of what you see on the screen to help us better identify your issue Something sounds add and I'm confused.

Well you won't see squat now its daylight. but I attached some iphone photos from last night.

Let me make clear- you can see everything in total darkness. The TV works in total darkness. I ran patterns on it last night, every inch of the panel works. Just literally dark even with backlight on.

The backlights are lit- I pulled the panel, proved that & I can see the backlight is on thru the holes in the back.

I suspect they are not bright enough to make the screen viewable. Does that help?


BTW: I did say this thing has demons. I'm betting the guy I got it from mucked around with it more than he let on. There was no logical reason for that cable issue, but I'm glad I tracked it down.

[budm]

Re: Sharp LC-60LE633U 2-5 flash

'+ to - leg is 75V for each pair at the PSU connector and at the actual strip' We need the reading with ref to GND not between the + and -.

[calimark]

Re: Sharp LC-60LE633U 2-5 flash

'+ to - leg is 75V for each pair at the PSU connector and at the actual strip' We need the reading with ref to GND not between the + and -.

+ve to GND is 132V
-ve to GND is 206

That is for each one. Hence the 74V on each pair


Should that 206V be sinking to GND? Making the led voltage 132?

[budm]

Re: Sharp LC-60LE633U 2-5 flash

Typical LED driver: The Negative wire of the LED string is the Cathode which is sinked to ground through the PWM controlled power MOSFET and the current sensing resistor for current feedback to maintain constant current.
Th + is the Anode of the LED string which is fed by the boost converter power supply.
If you look at the board layout, all the L1+~4+ are tied together and fed by the switched power MOSFET Q7223, the filter caps are C7200, 7201.
The PWM controlled sink power MOSFET Q7201, 7206, 7207, 7208 are for each LED strings (4 strings), and the 4 PWM controller ICs 7201, 7204, 7205, 7206 are for driving the PWM ICS. I do not see boost converter being used on this board.