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Old 03-18-2012, 09:50 AM   #1
thomas280z
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Default Sharp Lc37sb24u No Picture/audio

I am currently working on a Sharp Lc37sb24u. I was originally thinking it had a bad inverter board or power supply. There is not video or audio. When i turn it on, the green power light comes on for approx 5 seconds, then the power light and the OPC light blink twice, then the OPC light blinks three times. Then it repeats this sequence, the power light and the OPC light blink twice, then the OPC light blinks three times. Is there anywhere that tells what this sequence means? I've read where it could be a bad inverter board or power supply. Any help would be appreciated. Thanks!!
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Old 03-18-2012, 10:14 AM   #2
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Default Re: Sharp Lc37sb24u No Picture/audio

Here's the service manual: http://elektrotanya.com/sharp_lc-37s.../download.html (wait 1 minute for the Get Manual link to appear.)

The service manual appears to cover the differences between your model and the similar LC-37D44U, which has a service manual here: http://elektrotanya.com/sharp_lc37d4.../download.html

Flash timings are on page 52.

Two flashes indicates power failure; three indicates communication failure with main CPU.

I would suggest you start by disassembling the TV and checking it over for visually bad capacitors. Take pictures of the power supply connectors, of each board and an overall shot of the TV.
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Old 03-31-2012, 10:41 AM   #3
thomas280z
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Default Re: Sharp Lc37sb24u No Picture/audio

Here I some pics of the boards. None of the capacitors show signs of being bad. I checked for cracked solder on the two boards in the pics, didnt see any but I imagine there hard to find if they are cracked. I did a reset, hold channel down and up volume buttons while plugging the TV in. I now get a green "on" light and a blue screen but nothing else. Thought about just buying a used power supply board and trying that. Any suggestions would be appreciated.
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File Type: jpg TV Boards.jpg (392.5 KB, 43 views)
File Type: jpg TV Boards1.jpg (320.9 KB, 40 views)
File Type: jpg TV Boards2.jpg (372.8 KB, 37 views)
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Old 03-31-2012, 11:05 AM   #4
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Default Re: Sharp Lc37sb24u No Picture/audio

Sorry double posted in error- bad start eh?

Last edited by selldoor; 03-31-2012 at 11:08 AM..
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Old 03-31-2012, 11:07 AM   #5
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Default Re: Sharp Lc37sb24u No Picture/audio

Pics are not quite sharp enough we really need to be able to see the board designations. Please can you also post a pic of the bottom of the power board.
When you say you have a blue screen does it stay on like that? does the OSD come on? have you tried with a different input - PC/ DVD?

Have you a multimeter and can you use it?
Whilst you are now going to test low voltages (max prob 24v )areas of the board could be at 300-400volts so care is needed.
With the tv on and all boards connected, set meter on DC Volts put the black probe on the top right board fitting screw or the metal plate on that hole and with the red probe test each pin on the two white sockets at the top ( In your Picture 2) of the board. Make a list of pin no what designation it has on the board beside it and the voltage you get on test.
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Old 03-31-2012, 06:53 PM   #6
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Default Re: Sharp Lc37sb24u No Picture/audio

Not sure what you mean by board designations? Here's what happens. If I have the back on it, I do the reset, and the blue screen comes on, but no OSD, and the green power light stays on. If I reset it with the back off, I do not get the blue screen. The green power light comes on for approx 5 seconds, then the power light and the OPC light blink twice, then the OPC light blinks three times. I tested the voltage as you stated and only one pin, the 10 pin on the the 12 pin connector, had any voltage, which was 5v. I've attached a pic of the bottom of the PS and of the pin connectors. Thanks
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File Type: jpg power supply.jpg (362.3 KB, 32 views)
File Type: jpg ps connectors.jpg (276.8 KB, 29 views)
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Old 03-31-2012, 08:49 PM   #7
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Default Re: Sharp Lc37sb24u No Picture/audio

I also noticed that this relay(red box in picture) actually clicks "on" when the TV is first plugged in. At that time I get 37V at pins 1-4 on the 12 pin connector, then after about five seconds, the relay kicks "off" and the voltage to these 4 pins goes to zero volts. This is also when the power and OPC lights begin to flash.
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Old 04-01-2012, 01:20 PM   #8
thomas280z
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Default Re: Sharp Lc37sb24u No Picture/audio

Correction: I meant to say "I also noticed that this relay(red box in picture) actually clicks "on" when the TV is first plugged in. At that time I get 13V (not 37V) at pins 1-4 on the 12 pin connector, then after about five seconds, the relay kicks "off" and the voltage to these 4 pins goes to zero volts. This is also when the power and OPC lights begin to flash.
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Old 04-01-2012, 02:24 PM   #9
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Default Re: Sharp Lc37sb24u No Picture/audio

if you unplug everything on the power board (apart from the mains) and plug the mains in does the relay still click in after 5 seconds?
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Old 04-01-2012, 08:16 PM   #10
thomas280z
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Default Re: Sharp Lc37sb24u No Picture/audio

If I unplug the two white connectors, then plug the TV in, I get no clicks on the relay, either on or off.
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Old 04-03-2012, 06:43 AM   #11
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Default Re: Sharp Lc37sb24u No Picture/audio

check D7116 its a zener diode, doesnt look like the others in the same pic, looks black inside (could be just differant make) but might be worth a check to see if its bust

#6 pic 2
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Old 04-03-2012, 06:47 AM   #12
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Default Re: Sharp Lc37sb24u No Picture/audio

you could also, disconnect invertor board and just plug main board in and see if it clicks twice again
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Old 04-04-2012, 08:14 PM   #13
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Default Re: Sharp Lc37sb24u No Picture/audio

I unplugged the inverter board and get no clicks on the relay. Only when I plug in the two white connectors does it click on and off as described in the previous post
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Old 04-04-2012, 10:01 PM   #14
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Default Re: Sharp Lc37sb24u No Picture/audio

My sharp 52d62u clicks on when first plugged in then after a few seconds clicks again for standby. A 40" dynex does the same thing and a 50" philips plasma does it too. I just checked my sharp and when it is first plugged in and it clicks on the main board flashes a red led, then when it clicks off the led goes out and the standby light is on in the front of the tv. It may be a diagnostic thing.

Last edited by Mr Bill; 04-04-2012 at 10:05 PM..
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Old 04-09-2012, 04:46 PM   #15
thomas280z
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Default Re: Sharp Lc37sb24u No Picture/audio

Anyone?
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Old 03-04-2013, 09:52 AM   #16
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Default Re: Sharp Lc37sb24u No Picture/audio

Quote:
Originally Posted by thomas280z View Post
I am currently working on a Sharp Lc37sb24u. I was originally thinking it had a bad inverter board or power supply. There is not video or audio. When i turn it on, the green power light comes on for approx 5 seconds, then the power light and the OPC light blink twice, then the OPC light blinks three times. Then it repeats this sequence, the power light and the OPC light blink twice, then the OPC light blinks three times. Is there anywhere that tells what this sequence means? I've read where it could be a bad inverter board or power supply. Any help would be appreciated. Thanks!!
I am having exactly the same symptoms from the same model. Were you able to fix this? What was wrong with it? Thanks..
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Old 09-24-2013, 04:07 AM   #17
Xoyourheroox
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Default Re: Sharp Lc37sb24u No Picture/audio

Has anyone had any luck with a fix for this issue? Have the same tv with same problem. Tv has been sitting collecting dust and its time to fix it. Can anyone help out? Thank you for your time.
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Old 09-28-2013, 09:15 PM   #18
rmac4411
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Default Re: Sharp Lc37sb24u No Picture/audio

I was wondering if anyone could tell me the number off of the smd resistor on the b side of the main board? I took the board out of the tv and noticed that it had broke in half. It is located near ic 9601 by a smd diode marked v6 81. I know it has a 3 or an E on it because thats the only piece I have of the resistor. Thanks in advance!
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Old 03-04-2014, 02:03 PM   #19
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Default Re: Sharp Lc37sb24u No Picture/audio

On this model tv can anyone tell me where the main CPU and the monitor microprocessor are located? Would I be wrong in saying they are both located on the main board?

Last edited by Dustin862; 03-04-2014 at 02:26 PM..
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Old 03-04-2014, 02:32 PM   #20
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Default Re: Sharp Lc37sb24u No Picture/audio

I think that would be correct. The monitor processor is hooked into the power LEDs typically. You can follow it on a schematic, if you have one available.
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