Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I think bud was right with his initial diagnosis. Ccfl inside the panel or bad inverter.

The inverters tested alright, I will go back to the Troubleshooting 2 Seconds to Black and attempt to test the CCFL's. I have a tv with a busted screen, that still came on, could I use a bulb out of it to do this?

I'm going to try to jump the bulbs over, if I hit one and the screen stays on that should tell me which one is bad, if one is bad, or so I'm hoping. Will report back.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

Jumping them over and powering up only did the same thing it's been doing, flashing the logo then going black. So if the bulbs are bad, then my test didn't work and I need to get a spare bulb, or it's something else.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

Ok, so I figured I had nothing to lose, since it's already out of whack anyhow, so I just started taking a plug off, powering on seeing what happened and plugged it back in then unplugged another and so on, just seeing what would happen.
Well, here's what happened, I pulled a connector that ran from the Inverter Board to the Main Board and it says CN4 on the main board, I am pretty sure I tested these points in CN4 with bud and it checked out, so I thinking the problem lies within the Inverter Board (the one with the three transformers), instead of a logo flashing and going back off, the logo fully lit for 5 seconds, and a box appeared after the logo disappeared which I believe states No Signal, something to that effect, and then the TV powers off again... I'm not sure if this is helpful to my case at all, but I felt it was worth sharing, and possibly eliminates something somewhere. If anyone can chime in please do, and thank you again for all of your time and patience.

[budm]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

OK, we can try having one of the six lamp connected one at a time to see which one will not light up the screen, this is not 100% test to verify if the lamp is really bad or not but it may show us that one of the lamp may not light up.
The screen will flash for seconds before it goes into safety shutdown, you will have to turn the TV off and move on the to the next connector and then turn the TV on, do that six times for all six lamps.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

OK, we can try having one of the six lamp connected one at a time to see which one will not light up the screen, this is not 100% test to verify if the lamp is really bad or not but it may show us that one of the lamp may not light up.
The screen will flash for seconds before it goes into safety shutdown, you will have to turn the TV off and move on the to the next connector and then turn the TV on, do that six times for all six lamps.

They all equally flashed the same brightness, I was also able to see the Spectre logo in doing it as well. What was so shocking with unplugging connectors was when this 2 seconds to black is happening, it doesn't even seem as if it is Literally 2 seconds it just flashes and it's gone, but when I unplugged the connector the logo was fully there. I'm thinking it isn't the CCFL's, through reading the 2 seconds to black troubleshooting guide I read a spare bulb doesn't have to be the exact size so if all else fails I will break it down and start swapping bulbs. I figured the connector, since the pin's on CN4 checked out lead to something on that inverter board that is causing the problem, I'm just not sure what, then again I could be completely be barking up the wrong tree since I'm new to all of this thanks again bud

[budm]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

CN4 is for feedback from the inverter board to tell if there is problem with inverter, lamps and tells the inverter circuits on the power supply board to go into shutdown, I am not sure what the normal voltage should be for the OVP, CNT-PRT, LD should be.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I'm going to upload a photo of the logo when it pops up without the cord connected, I'm not sure if this is any count either of how it actually appears, or just because of the cord, but maybe it will shed some light.

The images look garbled/discolored to me.. that could have something to do with the connector not being connected, I'm not sure how it all works.. just thought it might add insight or it may be nothing.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

CN4 is for feedback from the inverter board to tell if there is problem with inverter, lamps and tells the inverter circuits on the power supply board to go into shutdown, I am not sure what the normal voltage should be for the OVP, CNT-PRT, LD should be.

so what should I do?

[budm]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I really do not know. You may try making test lamps.
https://www.badcaps.net/forum/showthread.php?t=19987

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I really do not know. You may try making test lamps.
https://www.badcaps.net/forum/showthread.php?t=19987

I will check into that bud, thank you for all of your help and patience. I may also try to price a CCFL and see if it's within reasonable price range as well before proceeding since that may be what I"m looking at. Thank you again so much.

[johnboy1313]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I was able to diagnose a bad transformer output on a 46" RCA on my bench by laying a loose bulb across the outputs of the transformers. Swapping the transformer moved the unlit spot on the bulb. Looks like I deleted my picture, but it looked very much like the picture in the first post.

https://www.badcaps.net/forum/showth...light=46la45rq

[Andrew F. Ali]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I had a similar experience with the same type of symptoms on another TV. On the Main Board located somewhere near the EEPROM and Flash ICs there is a 14.31818Mhz Crystal. Replaced this crystal and TV started to work again.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I was able to diagnose a bad transformer output on a 46" RCA on my bench by laying a loose bulb across the outputs of the transformers. Swapping the transformer moved the unlit spot on the bulb. Looks like I deleted my picture, but it looked very much like the picture in the first post.

https://www.badcaps.net/forum/showth...light=46la45rq

I will look into that. I have a 42" TV with good bulbs just a literal hole through the screen from a toy, if I read correctly on troubleshooting two seconds to black I can use that bulb to do a swap and see if they're all lighting. I think the inverter board for this TV is only $22, if it doesn't fix your TV are you allowed to return? I was leaning towards Ebay, but Shopjimmy.com has one as well. Thank you

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I had a similar experience with the same type of symptoms on another TV. On the Main Board located somewhere near the EEPROM and Flash ICs there is a 14.31818Mhz Crystal. Replaced this crystal and TV started to work again.

Andrew, I will research the EEPROM and Flash IC for this TV, as I'm not certain right off hand where those are located. Thank you again for your help and suggestions.

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

Ordered a new inverter board since it was relatively cheap, the issue still persisted. I went ahead and dug deeper and opened the panel up to the CCFL's, and all appear to be fine. I'm not sure if they can appear to be fine and not be, but I will attach a picture of them all lit.

Not sure what to do from here

[juicedlime]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I was able to diagnose a bad transformer output on a 46" RCA on my bench by laying a loose bulb across the outputs of the transformers. Swapping the transformer moved the unlit spot on the bulb. Looks like I deleted my picture, but it looked very much like the picture in the first post.

https://www.badcaps.net/forum/showth...light=46la45rq

I performed this test on the new inverter board, it was evenly lit up all across, so the inverters are good.

[gamethriller]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

Bad eprom maybe?

Or not bad for the wrong tv.....did you replace the mainboard?

[gamethriller]

Re: Sceptre X405BV-FHD3 Powers on, logo appears, then shuts off

I replaced the eeprom on the new motherboard. I took the original eeprom from the bad board and now the tv works.