June 05, , am. Home Help Search Login Register. Send this topic Print. Just a shot in the dark here The video itself is working
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June 05, , am. Home Help Search Login Register. Send this topic Print. Just a shot in the dark here The video itself is working Found a couple caps that were swollen, changed those. The fuse on the inverter itself is still good. Nothing else obvious and most of what's left is surface mount stuff.
What I really need to know is what the pinout would be to verify if it's the inverter or the signal telling it to turn on. Namely what would pin 5 be for? Lots of smaller inverters laptop run on 12V, not , so 12V isn't unreasonable. Pin 4 sounds like an on-off signal. Pin 5 may be a brightness control. Check to see where it runs. On some inverters, you just PWM the on-off signal, while others do the PWM onboard and have an analog signal for brightness usually current based, not voltage.
If you happen to have a scope, easy way to see if things are churning is to look for some sort of AC multimeter probably won't pick it up, but a true RMS might at the input to the transformer. They're just flyback converters, much like that found in a TV set but with lower output voltage.
Quote from: qrz on April 08, , pm. Quote from: MonMotha on April 08, , pm. Quote from: Kevin Mullins on April 08, , pm. Quote from: qrz on April 09, , pm. Flashman Trade Count: 0 Jr. Hello, I was googling around looking for some tips to troubleshoot such an Ambit inverter. Quite the same Philips TV set but the 15 inches one. Sometimes I've got the backlight at once, sometimes it doesn't want to start. Since I've open the TV it works normally should have get afraid of the soldering station: So I've been able to measure the various voltage you mentionned and found the same.
A bad solder joint? I have resoldered a lot of them. Without scope I can't help about the brightness control system but by experience on other inverter, even without signal on this input you can get the inverter on. About your trouble, I'm quite sure the two electrolytic caps on your board are dead and I suspect the two plastic grey caps to be the source of our common trouble.
A 12V one? This question because I don't understand why your circuit get so hot. Greetings from France,.
Thanks for joining the forum and welcome. Quote from: Flashman on April 10, , am. Quote from: Flashman on April 10, , pm. Just wanted to throw a couple pics up in case anyone else is searching for this sort of thing. The cap circled in RED is the one that kept the inverter from coming on properly. The stuff circled in green are all suspects in need of changing even though the TV is technically "functioning". The small round black ones on the main pcb are ones I need to identify still.
They appear to have what I can only describe as a circular "sweat mark" on the tops of them as if they had run hot as well. The only marking on them is a JPG Those little gray cans marked "" look like they could be inductors, not caps. Tough to tell from the pic. Quote from: MonMotha on April 10, , pm. I've just make a little test : the 5th wire brightness control disconnected from the connector prevents the backlight to come on.
So it is in contradiction with what i'm used to with some other inverters I have repaired before. Well, this give a clue to where we should look and it is not the inverter even if resoldering some joints on this board may have cure my problem. It has run for a while now and it's amazing how hot the chips on the mainboard get. I haven't noticed it before but the silicon can stand it better than my fingers. Been doing a little capacitor moving around just because I don't have enough new ones at the moment to just go ahead and replace them.
And there are 5 identical 25vuf on the main pcb. Went back to it later on to poke around some more and it wouldn't come on at all this time. It also did NOT get hot. Everything seemed to be of "normal" temperatures. So I just let it sit with power on for awhile to see what it would do. Eventually the screen finally came on after minutes and then everything started getting hot again.
I also put the known dead cap in that spot and the screen would never come on. So it seems there are at least a couple of those identical caps that will cause the inverter not to come on or have issues of sorts.
This also tell me some of the other caps are probably about dead and this may indeed be leading to the overheating issue. And my best suggestion at the moment would be to just replace them all. NOTE - Also noticed earlier that any time the inverter was not getting a signal to pin 5 there is an audible ticking from somewhere around the main pcb.
So this could be a clue for someone wondering if they have a bad inverter or not during troubleshooting. The cap I'm referring to now is circled in RED. It works well but since I opened it up it keeps on working and so can't really tell any difference. Maybe the OSD is more stable on the snowy image you get without an antenna connected.
Anyway the scaler board still gets very hot and the OSD shows then some little flickering. It would be interesting to look with a scope if the power adapter delivers a clean voltage Googling with the scaler ref. A never ending story those bad caps. Hope you can repair yours as the dot matrix it is equipped with is very good and provides a really sharp image connected to a PC.
PS : the. You can find the coil symbol on the other PCB side. Well, it looks like both of these use the same LC03 Scaler board, so I'm assuming most will be the same aside from the actual LCD size. I compared those cap lists and couldn't find a few of them either. I'll poke around it some more and look again.
I found all but caps they have listed. They also seem to use higher voltage rated caps, so maybe they'll hold up better because of that as well. I did some more googling and came across this though: Philips LC03LAA Manual Looks to have both some users manual information as well as service information that may be of some help.
I've only browsed through it at the moment I was able to download it, but only after registering and all that. I would just post it here, but the file is like 26MB. Quote from: Flashman on April 11, , am. Many thanks for the link to the service manual and, not to forget it, the help you provide. I have reassemble mine and I consider it as repaired.
Hope you can fix yours as well. Quote from: Flashman on April 12, , pm. Hi Kevin, Unfortunately not, the scaler board still gets very hot in few minutes while testing the repair. The service manual is really well done and even provides the inverter schematic, parts list and functionnal description.
But however if a 5v circuit monitor is built-in there is no clue of any thermal protection in this system. Quote from: qrz on April 12, , pm. Kevin, You now raise my own curiousity! Will it keep on running hot or not? Please let me know when you get them changed. QRZ, If I understand correctly you wonder which model does this chassis manual on about?
Quote from: Flashman on April 13, , am. Hi, Have you got some news? Not yet But will get back to this one soon. SMF 2.
Ambit T18I055.01 CCFL LCD Inverter
I have a Latitude C for 6 months. The screen always flickered and today it went off permanently. I tested the backlight lamp with another inverter card from a different system and the light went on OK. So, I blamed my inverter card. I considered buying a new card or a new lcd panel on ebay but I am having some compatibility doubts.