Sharp lc-60le650u lightning strike; will not power on

[hambone1234]

I am trying to diagnose a Sharp LC-60LE650U. This TV was mounted outside under a porch and previously working. A lighting strike on the house took out a bunch of AV equipment including this TV. The TV will not power on at all. I have verified the fuse and checked some of the pins going to the main board for voltage. Most read around 46Volts with a couple at 3-4 Volts. There are 24 pins on the plug and I am not sure about the orientation as to which one is "one" etc. I don't see any expanded CAPS or burn marks, but I have not taken the power supply board off the TV and looked underneath. Does anyone have any suggestions on where to start or what to look at? I have replaced board components on other TV's with success, but I can not find any detailed information on this model.

Thanks,

[freakaftr8]

Re: Sharp lc-60le650u lightning strike; will not power on

First of all we need to verify if you are getting voltage at the power supply PFC circuit. On the large capacitors on the primary side what are you getting for dc voltage across the negative and positive lead? Also 46 volts on the mainboard does not sound right are you sure you're monitoring on DC voltage? And of course a clear picture of the power supply would help front and back

[hambone1234]

Re: Sharp lc-60le650u lightning strike; will not power on

I am reading 172 VDC across both the long big caps on the bottom of the picture.

[freakaftr8]

Re: Sharp lc-60le650u lightning strike; will not power on

Ok what are you getting for dc voltage on pd-24 for standby voltage? This pin is the top pin on the right farthest from the black wires you can probe it from the top of the board.

[hambone1234]

Re: Sharp lc-60le650u lightning strike; will not power on

As of right now none of the pins have any voltage. I used the negative on the capacitor for reference as I could not determine a negative pin. Initially all the tops pins had ~5VDC on them. I pressed the power button to see what change would occur and they all dropped to 0. I unplugged the set for around 15 minutes and plugged it back in and still all at 0. In general the readings I have gotten on the pins have not been consistent.

[freakaftr8]

Re: Sharp lc-60le650u lightning strike; will not power on

Something seems odd. You had no flashing error code on the TV?

You had the board in the TV and you press the power button on the TV while you're monitoring DC voltage on the output pins and that's when everything drop to zero and now won't come back? You still have 174 volts roughly at the two capacitors?

Also do not monitor this with the ground of your voltmeter on the ground of the capacitor use the ground lug of one of the screw holes instead

[hambone1234]

Re: Sharp lc-60le650u lightning strike; will not power on

There was no error code. The TV will not power up at all. I just have the back cover off. Everything is installed right now during the checks. The screws don't provide a good reference. I can not get a solid reading from a screw to the caps. I can get readings from the negative on the cap to other misc.components. I still have the 174 on the caps.

[budm]

Re: Sharp lc-60le650u lightning strike; will not power on

When you make the DCV measurement on the seocndary (cold side) you will use GND on the connector or chassis GND.
When you make the DCV measurement in the Hot side, you will use negative leg of the main filter cap as the GND ref point for the meter.

[johnboy1313]

Re: Sharp lc-60le650u lightning strike; will not power on

I had the 52" version of this set a while back. The PSU was fried as was the HDMI section of the main. It wound up being an expensive fix.

[budm]

Re: Sharp lc-60le650u lightning strike; will not power on

Check the DCV between the two legs of C7950B.
BTW, you can run the power supply board by itself to check the standby Voltage.

[johnboy1313]

Re: Sharp lc-60le650u lightning strike; will not power on

I had the 52" version of this set a while back. The PSU was fried as was the HDMI section of the main. It wound up being an expensive fix.

I should have stated, it was struck by lightning as well.

[budm]

Re: Sharp lc-60le650u lightning strike; will not power on

I will not be surprised if the HDMI section is damaged.

[hambone1234]

Re: Sharp lc-60le650u lightning strike; will not power on

The DCV between the legs of C7950B is 0. I checked C7950A as well and it is 0.

"When you make the DCV measurement on the secondary (cold side) you will use GND on the connector or chassis GND.
When you make the DCV measurement in the Hot side, you will use negative leg of the main filter cap as the GND ref point for the meter. "

I am not sure how to determine what is the cold side and hot side on the board.

[budm]

Re: Sharp lc-60le650u lightning strike; will not power on

The DCV between the legs of C7950B is 0. I checked C7950A as well and it is 0.

"When you make the DCV measurement on the secondary (cold side) you will use GND on the connector or chassis GND.
When you make the DCV measurement in the Hot side, you will use negative leg of the main filter cap as the GND ref point for the meter. "

I am not sure how to determine what is the cold side and hot side on the board.

OK, I will have to trace out the STBY section of the board, there may be a fusible resistor for feeding the B+ to run the STBY SMPS section.

[hambone1234]

Re: Sharp lc-60le650u lightning strike; will not power on

It looks like i could get a complete replacement power supply board for ~80.00. Is there any way to determine if any other equipment on the TV is damaged without replacing or repairing the power supply board first?

A refurbished model of this TV can be purchased for about 700.00. I am trying to determine if this is worth fooling with or not.

This is a friends TV that was going to be trashed so if I fix it I get to keep it.

[budm]

Re: Sharp lc-60le650u lightning strike; will not power on

I would inspect main board around the HDMI areas really well to see if there are burnt or damages in that section. I will not be surprised if the main board is also damaged.