Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Vizio, no picture

On Friday, October 2, 2020 at 7:30:38 PM UTC-4, wrote:
On Friday, October 2, 2020 at 2:09:40 PM UTC-4, Stu jaxon wrote:
On Friday, October 2, 2020 at 7:39:45 AM UTC-4, wrote:
On Thursday, October 1, 2020 at 10:38:08 PM UTC-4, Stu jaxon wrote:
On Thursday, October 1, 2020 at 7:56:55 PM UTC-4, wrote:
On Thursday, October 1, 2020 at 3:13:29 PM UTC-4, Stu jaxon wrote:

8 led strips are out/shorted,.. do i look for shorts in the power supply or led driver board?? this isn't my tv .
Most late model TVs have LED issues, and it's usually inside the display. That one you have is a real toilet. Does the LED harness plug into CN802 on the main???
there are two harnesses that plug into the led driver board #715G7159-P01-000-004K cn801, cn802,
CN801 is the harness that goes to the LEDs. If you get no flash whatsoever (however briefly), then you most likely have a bad main board. Even a bad LED strip would allow a short flash of the others before shutdown. The only very rare exception is if this is one of those models that doesn't shut down the LED driver with an open string, and the customer kept watching it as each of the 5 strings died one by one over several months. I've only seen a couple of models that would continue to run with open strings. You really need an LED tester (0-300 volt) that are widely available for less than $50.

I have a GJ2C LED TV Backlight Tester.. and i believe it shorted some of the ones i was testing, I was testing some string strips individually, and some led,s came on others didn't, heard a sizzle, tested again, the whole string was dead. so i tested the rest with a variable power supply and salvaged six strings, ordered 10 more from ebay.. so do i test the main board for shorts before installing them, how would i do that???

That tester generally won't damage any strips since it's limited to 20ma or so, although I make it a habit of not reversing the polarity of the tester ever just to be sure. While most strings won't be bothered by the tester being connected backward, there are some that will short out the LEDs, particularly if they're already old and have a lot of heat and hours on them. In any case, make damned sure you remove the harness from the LED strips to the main, or you most likely will damage the low side drivers or the IC itself (in your case, it's a combination processor and driver).

If you had even a few LEDs not light while others did, your problem is most likely confined to the back light. Replace the LED strips with new ones and it should go. If you used the tester with the LEDs connected to the main you may have damaged the main as well.



I changed the strings/strips for the backlights still no pic, only getting 25v dropping to 16v on the connection harness to the backlights, when turning on the tv..
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Default Vizio, no picture

On Wednesday, October 7, 2020 at 3:40:55 PM UTC-4, Stu jaxon wrote:
On Friday, October 2, 2020 at 7:30:38 PM UTC-4, wrote:
On Friday, October 2, 2020 at 2:09:40 PM UTC-4, Stu jaxon wrote:
On Friday, October 2, 2020 at 7:39:45 AM UTC-4, wrote:
On Thursday, October 1, 2020 at 10:38:08 PM UTC-4, Stu jaxon wrote:
On Thursday, October 1, 2020 at 7:56:55 PM UTC-4, wrote:
On Thursday, October 1, 2020 at 3:13:29 PM UTC-4, Stu jaxon wrote:

8 led strips are out/shorted,.. do i look for shorts in the power supply or led driver board?? this isn't my tv .
Most late model TVs have LED issues, and it's usually inside the display. That one you have is a real toilet. Does the LED harness plug into CN802 on the main???
there are two harnesses that plug into the led driver board #715G7159-P01-000-004K cn801, cn802,
CN801 is the harness that goes to the LEDs. If you get no flash whatsoever (however briefly), then you most likely have a bad main board. Even a bad LED strip would allow a short flash of the others before shutdown. The only very rare exception is if this is one of those models that doesn't shut down the LED driver with an open string, and the customer kept watching it as each of the 5 strings died one by one over several months. I've only seen a couple of models that would continue to run with open strings. You really need an LED tester (0-300 volt) that are widely available for less than $50.
I have a GJ2C LED TV Backlight Tester.. and i believe it shorted some of the ones i was testing, I was testing some string strips individually, and some led,s came on others didn't, heard a sizzle, tested again, the whole string was dead. so i tested the rest with a variable power supply and salvaged six strings, ordered 10 more from ebay.. so do i test the main board for shorts before installing them, how would i do that???

That tester generally won't damage any strips since it's limited to 20ma or so, although I make it a habit of not reversing the polarity of the tester ever just to be sure. While most strings won't be bothered by the tester being connected backward, there are some that will short out the LEDs, particularly if they're already old and have a lot of heat and hours on them.. In any case, make damned sure you remove the harness from the LED strips to the main, or you most likely will damage the low side drivers or the IC itself (in your case, it's a combination processor and driver).

If you had even a few LEDs not light while others did, your problem is most likely confined to the back light. Replace the LED strips with new ones and it should go. If you used the tester with the LEDs connected to the main you may have damaged the main as well.



I changed the strings/strips for the backlights still no pic, only getting 25v dropping to 16v on the connection harness to the backlights, when turning on the tv..


If you used the LED tester without disconnecting the harness from the main, you probably damaged the LED drive IC. Shopjimmy lists a complete board set for that TV at less than $40.
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