Hello all!
I have a 60" Sharp Aquos LCD TV Model# LC-60E69U. Came home one day and no power light, nothing.
Initial inspection of power supply shows no obvious blown caps/fuses/diodes. 24V bus is fine, 12V bus is fine, 5V bus is fine. 24V and 12V bus did not drop much under a 8 watt load. I'll have to find a 6V light bulb to test the 5V bus. I have downloaded the service manual for the tv (linked here ) and have gone through the first two "basic diagnostics." All Check OK as per the service manual. It basicly had me check a few voltage regulators, voltage levels on a few caps, voltage on some connectors on the main board, etc.
I just want to ensure that this isn't truly a power supply issue before I purchase a new main board. According to the flow chart on the service manual the next step is replacing of the main processor IC. I do have a SMD hot air gun to do this, however finding that processor may be difficult, and I've never replaced anything that large before. I don't have a pre-heat bench yet and I'm sure that would be required removing an IC of this size so I'm left with finding a main board replacement ($100-$140). If I can fix this at the compenent level I'd be one happy fella.... my username isn't just for kicks, heh.
This is the mixed voltage connector on the power supply, not sure of the actual PIN numbers but are in order as pictured.
Rated V | Actual V
1 | 12V | 11.48
2 | Blank
3 | GND
4 | GND
5 | GND
6 | 5V | 4.87
7 | 5V | 4.87
8 | 5VSB | 4.81
9 | STB | 4.02
10 | 5V | 4.87
11 | 5V | 4.87
12 | Blank
13 | Blank
The other connectors are a 12V/GND connector measuring 11.48 and many 24V all soldered together for the LED drivers, and are at 24.07V
According to the service manual the 5V standby supply is the yellow wire (Pin 8 per my picture/notes above) and the On/Off is Pin 7 (white wire). I'm not sure why the white wire is measuing 4.02V, maybe this is part of the issue? I would assume it should be "5V" (4.8 in my case) This is what has me questioning the main board being the issue and not the power supply. Not sure which way to go here. Unfortunately I had to sell my o-scope so I'm limited to what I can do with a DMM. Have a friend who might loan me a 1Mhz scope (nescessary to check CPU clock, etc) but if I can diagnose it without a scope that'd be great as he's really particular about loaning equipment.
Other random things I've tried:
Different combinations for resetting sharp (VOL+ & Input, VOL- & Input, CH+ & Input, CH- & Input, etc)
Unplugged both LED drivers incase there was short, however this should only affect 24V bus which the mainboard doesn't even see 24V, just the control wires to the LED drivers.
Unplugged LVDS cable
Unplugged IR/Power LED board
No matter what I essentially get no activity. As mentioned above I do get a 5V reference on the IR board, and the power LED is actually getting 1.5V and glows a VERY DIM red. (Dual color LED, blue cathode side has about 250mv, red cathode has 1.51V)
I tried to do as much home work as I could before asking for help, but I'm stuck now, and not sure how to diagnose further. Any help you can provide would be greatly appreciated! I'd even be willing to throw some beer $$ via payapl for anyone willing to help a guy out!
Thanks in advance,
poor_red_neck
I have a 60" Sharp Aquos LCD TV Model# LC-60E69U. Came home one day and no power light, nothing.
Initial inspection of power supply shows no obvious blown caps/fuses/diodes. 24V bus is fine, 12V bus is fine, 5V bus is fine. 24V and 12V bus did not drop much under a 8 watt load. I'll have to find a 6V light bulb to test the 5V bus. I have downloaded the service manual for the tv (linked here ) and have gone through the first two "basic diagnostics." All Check OK as per the service manual. It basicly had me check a few voltage regulators, voltage levels on a few caps, voltage on some connectors on the main board, etc.
I just want to ensure that this isn't truly a power supply issue before I purchase a new main board. According to the flow chart on the service manual the next step is replacing of the main processor IC. I do have a SMD hot air gun to do this, however finding that processor may be difficult, and I've never replaced anything that large before. I don't have a pre-heat bench yet and I'm sure that would be required removing an IC of this size so I'm left with finding a main board replacement ($100-$140). If I can fix this at the compenent level I'd be one happy fella.... my username isn't just for kicks, heh.
This is the mixed voltage connector on the power supply, not sure of the actual PIN numbers but are in order as pictured.
Rated V | Actual V
1 | 12V | 11.48
2 | Blank
3 | GND
4 | GND
5 | GND
6 | 5V | 4.87
7 | 5V | 4.87
8 | 5VSB | 4.81
9 | STB | 4.02
10 | 5V | 4.87
11 | 5V | 4.87
12 | Blank
13 | Blank
The other connectors are a 12V/GND connector measuring 11.48 and many 24V all soldered together for the LED drivers, and are at 24.07V
According to the service manual the 5V standby supply is the yellow wire (Pin 8 per my picture/notes above) and the On/Off is Pin 7 (white wire). I'm not sure why the white wire is measuing 4.02V, maybe this is part of the issue? I would assume it should be "5V" (4.8 in my case) This is what has me questioning the main board being the issue and not the power supply. Not sure which way to go here. Unfortunately I had to sell my o-scope so I'm limited to what I can do with a DMM. Have a friend who might loan me a 1Mhz scope (nescessary to check CPU clock, etc) but if I can diagnose it without a scope that'd be great as he's really particular about loaning equipment.
Other random things I've tried:
Different combinations for resetting sharp (VOL+ & Input, VOL- & Input, CH+ & Input, CH- & Input, etc)
Unplugged both LED drivers incase there was short, however this should only affect 24V bus which the mainboard doesn't even see 24V, just the control wires to the LED drivers.
Unplugged LVDS cable
Unplugged IR/Power LED board
No matter what I essentially get no activity. As mentioned above I do get a 5V reference on the IR board, and the power LED is actually getting 1.5V and glows a VERY DIM red. (Dual color LED, blue cathode side has about 250mv, red cathode has 1.51V)
I tried to do as much home work as I could before asking for help, but I'm stuck now, and not sure how to diagnose further. Any help you can provide would be greatly appreciated! I'd even be willing to throw some beer $$ via payapl for anyone willing to help a guy out!
Thanks in advance,
poor_red_neck
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