Sylvania LC320SS8 A turns on for a split second then black

[jasonbay13]

I got a sylvania model in title that has the standby light and when i press the power button the green light flashes like it should then the screen flashes with its "digital television" logo and then returns to its standby light state. i can press the power button to repeat the process.

I have not taken it apart yet to check for bad caps or other 'tronics.
will update when i get apart.

but any ideas, or maybe theres a common fix?

[jasonbay13]

Re: Sylvania LC320SS8 A turns on for a split second then black

finally have it set up and opened.
as you can see by the 2 images i've uploaded there are no bulged caps. i tested for shorted diodes (not the zener type) and output transformers all seem close to the same.

i have a few cfl test lights and a spare ccfl from a 17" monitor. i did try various combinations, but it made no difference. i also have a dmm, scope, and esr meter.
Better pictures can and will happen, when there is sunlight, which doesnt exist in the late pm.

Not sure what to check from here.

[capkid]

Re: Sylvania LC320SS8 A turns on for a split second then black

I remember reading about this issue a few years ago when I purchased John Preher's repair guide: http://preher-tv.blogspot.com/2010/0...-repaired.html

[jasonbay13]

Re: Sylvania LC320SS8 A turns on for a split second then black

i just checked all the secondaries as shown in that link. all were between 505 and 513 ohms.

[stj]

Re: Sylvania LC320SS8 A turns on for a split second then black

resolder the 4 big diodes.
it's probably not related to the problem, but obviously they get pretty hot.

[Caleb]

Re: Sylvania LC320SS8 A turns on for a split second then black

I just picked up a slightly smaller version LC260SS8, looks to have the same power board as yours. Mine has standby and the inverter board appears to be working. 172vdc on wires from inverter to power board. Voltage on output diodes climbs for a second when power button is pressed then drops back off. There doesnt appear to be any shorts beyond the secondary but I didnt get a chance to pull the power board and check the backside. Will try to check esr and look for shorted diodes on back of board tonight.

Yours sounds like the power board is working and the trouble lies on the inverter, do you still have sound after the backlight kicks off?

[jasonbay13]

Re: Sylvania LC320SS8 A turns on for a split second then black

the tv goes back into standby so there would be no input.

i'll resolder those diodes. though i think it is triggering the protect circuit, but why is the question...

[Comm]

Re: Sylvania LC320SS8 A turns on for a split second then black

Common problem, the leads to the CCFL's are breaking down and arcing to each other. You can insulate them with liquid tape or silicone. If you move the red wire away from the white wire you can see the breakdown, or even turn off your lights and look for the arc, but be careful of your hands

[Comm]

Re: Sylvania LC320SS8 A turns on for a split second then black

I guess I should clarify, pink wires, lol and whites. Also, I mean RTV or silicone sealant not silicone lube. You can also loop the wires and wire tie the excess length of wire to get them away from each other. Electrical tape will work also.

[jasonbay13]

Re: Sylvania LC320SS8 A turns on for a split second then black

thats the first thing i thought when googling. guess i forgot to mention it here. i had moved the wires so they wouldnt touch and still same result. i had 4 test lamps connect at once too, no difference.
and still havent gotten around to that resolderig yet... where do the days go

[johnboy1313]

Re: Sylvania LC320SS8 A turns on for a split second then black

Hard to tell from your pictures but a few of the wires from the inverter to the bulbs look to have arcing marks on them. Check out this post.

https://www.badcaps.net/forum/showthread.php?t=26417

[johnboy1313]

Re: Sylvania LC320SS8 A turns on for a split second then black

Guess I should have read the entire thread. Sorry.

[jasonbay13]

Re: Sylvania LC320SS8 A turns on for a split second then black

so, with further dis-motivation i set the tv aside for a good long while. i came back to it, on the bottom connecting to the corner pin #13 of a chip that the best i could try reading was ma9683 i found an exploded smd ceramic capacitor. i tried putting on another from a random board i had laying around (i have no idea how to tell value) but picked one of same size. the screen lasts almost two seconds now instead of less than half a second, but is still going black. all the output tansformers are good with ohms, electrolytics are good, regular diodes are good. no direct shorts on transistors.

bottom leftmost chip is one i am referring to, sorry for crap quality. i can get actual pic of board if you think theres a chance of getting it working. otherwise just tell me to forget it and i'll keep the boards for parts and toss the lcd.

[jasonbay13]

Re: Sylvania LC320SS8 A turns on for a split second then black

: i decided also to try the test lights again, 1-4 first which ended up with no difference. 3-6 it stayed on while the lights flashed like a strobe light, going to 4-6 the same happened, but strobed quicker. i tried going further by doing 5 & 6, but it shut off after a second, looks like if i have any of the ccfls plugged into 4,5,or 6 it shuts off. but with test light it stays on and strobes.