Sharp Aquos 32"

[rigeback]

Re: Sharp Aquos 32"

Hi Momaka, good to have you back!

Perhaps the last thing you could try is pull ANT+5V_SW high by using a 100 Ohm resistor to connect ANT+5V_SW to either a 3.3V or higher voltage rail. If the TV still doesn't come on (my guess is most likely it wouldn't)

You'll have to explain this part more clearly as I didn't understand from where to where I should hook up the bypass, which is cool by me. If it fails I might shop for a new board but I need to be certain that the PSU is not at fault here? It would be good to get this t-con going as it seems in fairly good shape. "The kitchen TV"

measure the voltages on pins 5, 19, 24, 25, 26, 27, 28, 30, 31, 32, 45, 46, 47, 50, and 51 of IC2302 and let me know what these voltages are. As a last attempt, I'll see if I can make some sense out of them.

I have measured the voltages on IC2302 as follows: 5=3.25V 19=3.25V
24=2.21V 25=2.21V 26=3.06V 27=2.91V 28=3.22V 30=3.22V 31=3.21V 32=0.01V 45=0.01V 46=0.01V 47=3.20V 50=0.03V 51=0.20V Shorting between pin 47 & 48 also suspends the lamps same as with IC2303.
Would be possible to eliminate the suspend mode to off and on, I think they use this mode in some hotels, no suspend mode to save power?

[momaka]

Re: Sharp Aquos 32"

Hi rigeback, sorry for the delay.
IC2302 does seem to be some kind of suspend switch as it has other pins related to the TV's power, like for example pin 24 AC_DET (AC detection), pin 26 BL_ERR (backlight error), and pin 47 PS_ON (signal for powering the PSU on).
I was able to find a data sheet for this IC but understood very little from it (perhaps because I didn't look at it in too much detail).
Anyways, I'm not really sure what to further suggest. The missing ANT+5V voltage rail may or may not be what's causing the problem (maybe that's normal?).
Perhaps the last thing you could try is pull ANT+5V_SW high by using a 100 Ohm resistor to connect ANT+5V_SW to either a 3.3V or higher voltage rail. If the TV still doesn't come on (my guess is most likely it wouldn't), then measure the voltages on pins 5, 19, 24, 25, 26, 27, 28, 30, 31, 32, 45, 46, 47, 50, and 51 of IC2302 and let me know what these voltages are. As a last attempt, I'll see if I can make some sense out of them.

[rigeback]

Re: Sharp Aquos 32"

So what you reckon Mr. Momaka is this one gonna make it or is beyond repair??

[rigeback]

Re: Sharp Aquos 32"

Yes you're right, I did a continuity check on this line ANT+5V_SW and IC1725 pin 1 goes to IC2302 pin 41, my meter has the diode / continuity test feature and it also gave some readings but no alarm, connecting with IC1725 pin 1 and IC2303 also BU3.3V and FB2310 which I trust is a fuse which has contiguity across.
Could be IC2302 is the suspend switch as when I probe it for voltage it shuts the lamps down or is duff?

[momaka]

Re: Sharp Aquos 32"

IC1755 Pin 1 gives 2.86V and pin 3 = 1.20V

The voltage going to IC1755 is a bit weak, but the output on pin 3 looks good at 1.2V, so I'll assume this is okay for now.

On IC1725 only pin 6 has 7.53V while the TV is on, Pin 4 is still 0.0V while TV is on or off! D1725 receives 8.16V and supplies pin 6 on IC1725 with 7.53V however the nearby caps C201 & C217 have no power?? Q204 ON THE UNDERSIDE HAS 5V supply and nothing on the opposite side?

Like I said, if pin 1 has 1.8V OR LESS, then there would be no voltage on pin 4 (the output). So the IC is likely working normally. However, I traced pin 1 (it's called ANT+5V_SW, and it goes to IC2302, pin 41. So basically, IC2302 controls whether IC1725 should be ON or OFF.
But that still doesn't explain whether this is normal behavior or not. I highly doubt IC2302 is bad, though. More likely something else is causing IC2302 to shut down.

Will look in the data sheet a bit more and let you know if I find anything else.

[rigeback]

Re: Sharp Aquos 32"

They are both in parallel so you should get the same voltage on all pins of these fuses.
Better yet, just check the voltage on pin 1 and pin 3 of IC1755. If pin 1 is 3.3V or close and pin 3 (the top tab) is 1.2V, then everything is OK with that rail.

IC1755 Pin 1 gives 2.86V and pin 3 = 1.20V

There should be 5V on pin 4 - but that's only if there is 1.8V or more on pin 1. Since pin 1 is 0V, then pin 4 is also disabled. I'm not sure if this is normal or not, though. I *think* the TV should turn ON this voltage regulator when it turns ON, but again, that's just a guess. Perhaps it turns ON only when the TV is OFF? I guess you should check that - turn OFF the TV and see if you get 5v on pin 4 of IC1725.

On IC1725 only pin 6 has 7.53V while the TV is on, Pin 4 is still 0.0V while TV is on or off! D1725 receives 8.16V and supplies pin 6 on IC1725 with 7.53V however the nearby caps C201 & C217 have no power?? Q204 ON THE UNDERSIDE HAS 5V supply and nothing on the opposite side?

[momaka]

Re: Sharp Aquos 32"

I re tested every thing and I found some lower values on VGH35V = 30.2V

Not sure about this one. Let's leave it for after we check the other items.

and also on the 2 fuses Next to IC1755 are 3.20V-2.80V both fuses same values across?

They are both in parallel so you should get the same voltage on all pins of these fuses.
Better yet, just check the voltage on pin 1 and pin 3 of IC1755. If pin 1 is 3.3V or close and pin 3 (the top tab) is 1.2V, then everything is OK with that rail.

And finally IC1725 = on pin 6 is 7.56v and the rest are 0.0 Volts??

There should be 5V on pin 4 - but that's only if there is 1.8V or more on pin 1. Since pin 1 is 0V, then pin 4 is also disabled. I'm not sure if this is normal or not, though. I *think* the TV should turn ON this voltage regulator when it turns ON, but again, that's just a guess. Perhaps it turns ON only when the TV is OFF? I guess you should check that - turn OFF the TV and see if you get 5v on pin 4 of IC1725.

If not, we might have a problem.

[rigeback]

Re: Sharp Aquos 32"

Yes, that's a problem. Check voltage om pin 2 (SW) and pin 4 (Vref) of IC4202

I must have miss probed this one as its okay today Pin 1 (Vin) = 3.21V, Pin 3 (Vo) = 2.45V pin 2 = 3.20V and pin 4 = 1.22V.
I re tested every thing and I found some lower values on VGH35V = 30.2V and also on the 2 fuses Next to IC1755 are 3.20V-2.80V both fuses same values across?

B+ANT5V --- IC1725

And finally IC1725 = on pin 6 is 7.56v and the rest are 0.0 Volts??
Thanks for all the help.

[momaka]

Re: Sharp Aquos 32"

Hi Momaka, most of the checks went well although I could not find C1706 or C1707, seems they forgot to print the board or I need new eyes or specks! the attached photo illustrates what I believe is the location.

Looks correct to me.

IC4202: Pin 1 (Vin) = 3.21V, Pin 3 (Vo) = 0.0V I think it has a problem

Yes, that's a problem. Check voltage om pin 2 (SW) and pin 4 (Vref) of IC4202

Here again IC4410: Pin 6 (IN) = 5V, Pin 1 (Out) = 0.00V Pin #3 also 0.0V

That one is fine. If the voltage on pin 3 (EN) is less than 1.8V, them the voltage on pin 1 (out) will also be 0V.

[rigeback]

Re: Sharp Aquos 32"

Hi Momaka, most of the checks went well although I could not find C1706 or C1707, seems they forgot to print the board or I need new eyes or specks! the attached photo illustrates what I believe is the location.

After this, look on page 4 of schematic Segment 004, lower right corner. IC4202 produces the B+2.5V_ST rail (a 2.5v standby rail - should be there whenever the TV is plugged in). Measure voltage on the following pins of IC4202: Pin 1 (Vin) = 3.3V, Pin 3 (Vo) = 2.5V

IC4202: Pin 1 (Vin) = 3.21V, Pin 3 (Vo) = 0.0V I think it has a problem

Finally, move to Page 5 of schematic Segment 004. IC4410: Pin 6 (IN) = 5V, Pin 1 (Out) = 5V (only if Pin 3 (EN) is higher than 1.8V). IC4410 is not actually a regulator but a switch.

Here again IC4410: Pin 6 (IN) = 5V, Pin 1 (Out) = 0.00V Pin #3 also 0.0V
Bear in mind that the screen connectors were disconnected for all the above since the board had to be rotated anyway.

[rigeback]

Re: Sharp Aquos 32"

One thing I can confirm is when I connect the screen ribbons I loose power to the t-con area VLS15.6V, VGH35V, and VGL-6V.
I have removed the ribbon connectors for the tests since some of the parts are located on under side of the board.

[momaka]

Re: Sharp Aquos 32"

Aaaand I just went through all of the schematics... whew.
There's so many things to check I don't even know where to start. It seems this TV uses at least a billion voltage regulators.

Since there's so many of them, I suggest you cycle the power to the TV every now and then, as in every 5 minutes. The reason for this is to prevent the TV from entering standby after a certain time (if it even does that). Ideally, it would be best to cycle the power before testing each regulator, but that's way too many cycles and is bad for the PSU, so cycling power every 5 minutes should be okay I think.

Also, disregard my post above about the voltage regulators. Segments 003, 004, and 005 of the schematics you uploaded in post #28 tell you all of the voltages that should be present on each voltage regulator.

Before you begin, take a note of how the schematics are drawn. Note that all of the power rails are drawn with thicker lines - these are the only rails we are interested in right now. Also, for most regulators, the output pin is denoted with Vo, the input as Vin, and ground as GND. On some of the regulators, like IC1702, IC1735, and IC1745, the output is denoted with SW, however you cannot measure the voltage on that pin since it is SWitched (i.e. pulsed DC). For these you measure at the output capacitors... I will tell you on which capacitors to measure.


I think the best place to start is page 1 of schematic Segment 005 since it has most of the voltage regulators. You will check the voltage on each and make sure it's good. I compiled a list of all of the voltage rails and which IC/voltage regulator is responsible for these rails:

B+3.3V --- IC1745 (for this one, measure the output voltage at capacitor C1745 or C1746, otherwise you may get erroneous results)
BU+5V --- none. BU+5V seems to come from BU5V (pin 11 of connector P1701) through two 1-Ohm resistors in parallel (resistors R1712 and R1711). Check to see if the resistance of these resistors is good. Should be under 3 Ohms, depending on how low your multimeter can measure.
B+ANT5V --- IC1725
S+8V --- IC1726
BU+3.3V --- IC1701
B+5V --- IC1735 (for this one, measure the output voltage at capacitor C1735 or C1736, otherwise you may get erroneous results)
B+1.8V --- IC1756
B+1.2V --- IC1755
BU+1.8V --- IC1702 (for this one, measure the output voltage at capacitor C1706 or C1707, otherwise you might get erroneous results)


Next, look on page 8 of schematic Segment 003, lower left corner. The following ICs should have the following voltages:
IC202: Pin 4 (Vin) = 5V, Pin 5 (Vo) = 3.3V
IC204: PIN 1 (Vin) = 3.3V, Pin 5 (Vo) = 2.5V
IC205: PIN 1 (VDD) = 2.5V, Pin 5 (Vo) = 1.0V


After this, look on page 4 of schematic Segment 004, lower right corner. IC4202 produces the B+2.5V_ST rail (a 2.5v standby rail - should be there whenever the TV is plugged in). Measure voltage on the following pins of IC4202: Pin 1 (Vin) = 3.3V, Pin 3 (Vo) = 2.5V

Finally, move to Page 5 of schematic Segment 004.
IC4410: Pin 6 (IN) = 5V, Pin 1 (Out) = 5V (only if Pin 3 (EN) is higher than 1.8V). IC4410 is not actually a regulator but a switch.


And that's all the regulators I saw so far. Also check VLS15.6V, VGH35V, and VGL-6V again. Let me know if any of the voltges are missing or way out of spec. Out of spec would be +/-5% of the stated voltage value.

[momaka]

Re: Sharp Aquos 32"

could be this be a duff screen or control switch??

Maybe, but I doubt it.

Will connect and re test each component next!

Yes, do that and see if the voltages disappear again.

I have downloaded the specs for the main sharp LDO's to gather information concerning the actual voltage out put, however accordingly this is controlled by the capacity of the in line caps so I am still not sure what to expect, any info much appreciated.

Pin 1 is the input to the regulator. This is the voltage that the regulator "uses" to "make" a new voltage.
Pin 2 is the ON/OFF switch - this is what controls whether the regulator should be working or not. The data sheets you posted for the 2 regulators both state that they (the PQ20WZ** and PQ070XNA1ZPH) will turn on only when the voltage on Pin 2 is above 2.0V.
Pin 3 is the output for these regulators. The regulator "takes" the voltage from pin 1 and converts it into a lower voltage. The output voltage on this pin depends on the voltage at pin 4.
Pin 4 - controls what the voltage on pin 3 is.
Pin 5. Ground (0 volts).
It may be possible to check if the regulator in question is outputting the correct voltage by measuring resistance between pin 4 and pin 3 as well as between pin 4 and pin 5. Both data sheets state that the output voltage, Vo can be found by the formula:
Vo = Vref * (1 + R2/R1)
Vref = 2.64V for the PQ20WZ** regulator and 1.23V for the PQ070XNA1ZPH regulator
R2 is the resistance between pin 3 and pin 4.
R1 is the resistance between pin 4 and pin 5.
This test my not be very accurate, but it should give you a good idea if the regulator is outputting the correct voltage.

I still haven't sat down and looked through the schematics, but I'll try to do that soon if I can.

[rigeback]

Re: Sharp Aquos 32"

Well guys you're gonna think I'm banana's but the power has come back again to the t-con and all test points. I decided to re test the t-con without connecting the screen ribbons and manual control board and things are normal again, could be this be a duff screen or control switch??
Will connect and re test each component next!

[rigeback]

Re: Sharp Aquos 32"

I haven't looked at the service manual yet, but I think tom66 has the right idea to check the rest of the voltage regulators. I see a few more.

Starting with this picture, check IC2303 (left-middle side of the picture, close to the 2 electrolytic capacitors):
https://www.badcaps.net/forum/attach...6&d=1324947839

On this picture measure voltage on the pins of IC4202:
https://www.badcaps.net/forum/attach...3&d=1324944651

I wonder what the 8-pin ICs with v5805 do. Check voltages on all pins and post back. I wonder if these could be 5v linear regulators.
https://www.badcaps.net/forum/attach...4&d=1324944651

Measure voltage on IC1755 and check the 2 fuses to the left of it.
https://www.badcaps.net/forum/attach...5&d=1324944651

Lastly, measure voltage on the pins of the IC between the antenna input jack and the card slot. The IC is right below electrolytic capacitor C4420. There's also a 3.3v test point to the right of C4420. Check if that test point gets 3.3v.
https://www.badcaps.net/forum/attach...2&d=1324333526

Mr. Momaka please swing by when you have a chance regarding the results for the above, thanks in advance and happy new year.

[rigeback]

Re: Sharp Aquos 32"

I have downloaded the specs for the main sharp LDO's to gather information concerning the actual voltage out put, however accordingly this is controlled by the capacity of the in line caps so I am still not sure what to expect, any info much appreciated.

[rigeback]

Re: Sharp Aquos 32"

Well took the back off again to check the lamps with power on and all are working fine, could catch a suntan with lamps like these. No, the problem lies within the power supplies to the t-con etc and I need to fined which LDO or cap is not working??

[rigeback]

Re: Sharp Aquos 32"

Could be possible although from the back side the lamps seem to working okay, I did have the screen open at one point but never powered it up, will have to open her up again to verify, thanks for the info.

[popeye]

Re: Sharp Aquos 32"

Have you tested the ccfl back lights they go on this model you will find one of the lamps at least is duff. You can buy a tester on ebay about £3 to test the back lights if you see any dull patches that the tube to replace. A certain amount of skill is needed not for the faint hearted.

[rigeback]

Re: Sharp Aquos 32"

Well the rest of the board has the same readings as indicated in message #27 although the 3 test points in the t-con area are still dead including 6V TP, theres 13V on the fuse and D8410 but the rest is dead???