Sharp Aquos 32"

[rigeback]

Re: Sharp Aquos 32"

OK, you're right Tom I've got 312V when I measure across the terminals, I was measuring with one probe to ground in the last post. One this comes to mind after reading other posts on the forum that this TV since I got it has never made that familiar click noise when I turn it on, I have an LG-50 plasma and it always clicks once when turning on?

[rigeback]

Re: Sharp Aquos 32"

Back to the main board with 12V external power source and it checks like there is a blown IC between suspend and 5V rail, its getting closer to the trash can!

[momaka]

Re: Sharp Aquos 32"

Given the multitude of possible problems presented so far, I think you should just put this TV in storage for now and return to it sometime later (maybe a few days? weeks? months?). Or perhaps not, I don't know... for me, this strategy has always worked. Sometimes I don't have enough experience to fix something, so I wait until I see more items with the same or similar problem. Other times I just happen to overlook things and it is only after I come back later that I can find what I overlooked and fix the problem.

[rigeback]

Re: Sharp Aquos 32"

You're right and the TV was in storage and I brought out again!! I'll keep it off the forum and trouble shoot it a bit more by myself. It would be great if this TV could be converted into a PC monitor but I guess that would be like reinventing the wheel.

[rigeback]

Re: Sharp Aquos 32"

Got some free time and would like to trouble shoot my power source. The TV back lights were working properly prior to the last trouble shoot which caused the set to go into protection mode, however even after bypassing the protection mode the back lights will not come on which leads me to think maybe the one of the transformers have a problem since all the diodes, mosfetts and resistors seem okay!
The set is still powering up with a red to green led for a few seconds and reverting to the red led. While the led is green most of the relevant startup voltages are present like PS_ON, BL_ON with 13V entering the main board.
Any ideas would be appreciated.

[rigeback]

Re: Sharp Aquos 32"

I want to revive this thread as I have too many parts laying around.
I retested the PSU yesterday and 13.2V is present while PS_On is bridged with BU5V although I have not managed to get the back lights on since the switching error that was caused by repeatably on/off while measuring voltages!
I also retested the area indicated in the attached picture regarding the diode D1703 thats reads 274 Ohms and 044 Ohms the other way, there are also a few resistors in IC1703 area that read 18 Ohms, D1735 and D1745 also have low readings and do not read OL in opposite readings??

[rigeback]

Re: Sharp Aquos 32"

Question? This board is holding a constant 38V even when its not plugged in and it stops at MOS7500 and MOS7501.
I opened back light panel tp recheck all connections and lamps and all seems well as before, the signal from the main board is being sent but the back lights cannot start.
There is a pdf on post 79 https://www.badcaps.net/forum/showpo...&postcount=79I regarding the cracking of the ceramic cap C7554 that causes back light error although this one seems to work 160 Ohms both ways.
Will post a better picture of the board tomorrow.

[rigeback]

Re: Sharp Aquos 32"

Just to make sure the PSU was supplying 12 volts I setup the car lamps as per Bud Martin's tutorial with a 5V DC external supply, there is no problem with the 12V supply on this board. Now I would like to try and get the back lights to run without the main board but not so sure how to make a dummy connection?

[rigeback]

Re: Sharp Aquos 32"

So I connected 5V and 12v to the the STB pin while my 12v car lamps were connected and the back lights came on briefly or more like a flash, could this be a bad caps issue or a bad transformer???

[tibimakai]

Re: Sharp Aquos 32"

...or bad ccf tube?

[rigeback]

Re: Sharp Aquos 32"

...or bad ccf tube?

I doubt it since I checked the tubes a few days ago including connections, this TV back light system was working fine until it exceeded the 5 errors caused while checking the main board, which does have a problem!

[Securityman]

Re: Sharp Aquos 32"

Just read the whole thread, you are giving a good shot. I hope to get there in the end.
I can see how lucky i am with the fault on my plasma now that i can see the work you have put into this panel.

[rigeback]

Re: Sharp Aquos 32"

Yes mate it will come together one way or another, been busy on a similar project regarding a samsung inverter problem which has certainly given some insights on this POS, its identical to post 44 https://www.badcaps.net/forum/showth...?t=8292&page=3 , I'm not going start another thread as the fault is the same as above, just more Chinese junk!

[rigeback]

Re: Sharp Aquos 32"

Well as I said after trouble shooting another TV the information assisted me getting my Sharp back on track with timing grounded on the OZ964 PWM Controller I got the inverter to work again with all the lamps working and did a check after 10 minutes to see if any of the inverters were hot, all good so far! I was a bit worried about this as some of the primary windings reading were a bit out although all secondaries were good.
One thing I'm troubled by is that without the car lamps in the 12V circuit the inverter shuts down, and I want to reconnect to the main board to find the short, preferably searching for a hot spot! Will this blow my PSU????

[rigeback]

Re: Sharp Aquos 32"

Another question? How WARM or HOT should a Alps tuner RTUDAA019WJQZ become to say its defective.
After confirming the PSU and inverters work I connected the PC / PSU to the main board as the source, got the reset to allow full ON and recheck all the voltages which inline with the manual, however there seems to be a short to ground of 1-2 volts, had the board running for about an hour and noticed the the tuner getting fairly warm, checked the other TV's and they do not seem to get this warm, Thoughts!!

[tom66]

Re: Sharp Aquos 32"

Another question? How WARM or HOT should a Alps tuner RTUDAA019WJQZ become to say its defective.
After confirming the PSU and inverters work I connected the PC / PSU to the main board as the source, got the reset to allow full ON and recheck all the voltages which inline with the manual, however there seems to be a short to ground of 1-2 volts, had the board running for about an hour and noticed the the tuner getting fairly warm, checked the other TV's and they do not seem to get this warm, Thoughts!!

I don't think there's a specification, but with most shorted semiconductors they rapidly let out the smoke or get very hot if shorted. The tuner will have a high performance RF front end and power consumption isn't an issue for most LCD TVs, so it might be fine for it to be a little warm.

[rigeback]

Re: Sharp Aquos 32"

Well thats good to know, thanks Tom.
This short must be very small as the board runs well and does not put any significant load on the PSU, This ATV RESET IC3002 is very sensitive when touched with a probe and comes out of standby, if I hold on longer it remains ON, I'm considering a jumper to see if I can run the TV to at least to clear the errors if I get a menu.