When the television button failed to respond, it was repaired for three days in exchange for three plates and found that it was not a problem at all。
I followed the online tutorial to demanify the machine, rubbing it in the face, measuring it, either high or low, or simply not counting。
The master said, "look at the 5vsb first," and i found half a day to touch the line on the power panel, and i touched the pen, 0. 2v -- lower than the phone's voltage。
Turns out there's a large safety barrier on the power plate, black, without a crack and drums, ringing with a watch bell -- broken. It's a 0. 5 euro switch. It's on。
But just relaxing, if you press a remote control or a black screen, you hear a "drop" like a cell phone lock, but the screen doesn't flash。
I went back to the main board, and the +3. 3v point was next to the remote receiver, and the pen was pressed up, 2. 1v. Check it out, there's clearly something wrong with a 3. 3v steady-pressure chip on the side, shrunk with one hand。
Take it down, there's a crack on the back of the chip, and the welding point turns yellow. Blowing down with a hot wind rifle, it was discovered that a white mark had been burned from the bottom of the pcb copper skin, as if electricity had broken through the road left behind。
Welded and measured +3. 3v, 3. 28v, steady. The remote access to the menu and the sound are normal, is that the image is covered in water fog, all of which are vertical gray bars。
Checked the lvds line, plugged it loose, followed by stripes, and then in half the time it was clear for two seconds, then fell back。
I rubbed the gold fingers on both sides of the lvds plug five times, and then i stuck them to the end, and then i hit them, and it was on, and the color was on。
It's not a broken plate. It's a 10-year-old tv. It's a needle oxidation。
I measured four key voltages on the logic board: vaa was 13. 6 v, vgh was 20. 3 v, vgl was 6. 1 v, vcom was 5. 4 v — all online, but not at first, afraid that the watch would be wrong, changed the watch, or the same。
Then the old maintenance notes found that the logbook h75e3a, the normal vgh value of the logic board was in fact 20. 5 ± 0. 5 v, and the 20. 3 v that i measured was, in fact, critical, but did not reach the failure threshold。
It's a real thing. It's a load of voltage. It's useless. I picked up a 5-w blocker for a fake load, then measured vgh, and fell to 18. 9 v... That's a real hammer. The little electric weld in the voltage circuit。
Light it up, check it, 20. 4 v, steady。
Some people in the maintenance group say, "the voltage is right, not necessarily good; the voltage is wrong, it must be bad."
I measured all afternoon and found that the numbers shown in the voltage table were sometimes “outcomes” and sometimes just “fakes”。
For example, the ps-on, the first time i had a crooked pen, i had a zero-v, thought the main plate was dead, and it turned into a line of heavy pressure, and it jumped to 4. 7 v, and it snapped, and the light on my back。
There was also a vgl test, a cross-reference to the graph, reading - 0. 3 v, shocking, re-searching, re-testing - 6. 1 v, to be firm。
The most dramatic is tcl l48f3380, which is red light, sound, menu motion, black screen。
I followed the outline, and vgh was normal, vagl was normal, vaa was normal, vcom was normal, lvds had a 102。
Finally, the lvds clk was flat, flat, on the back of the logic board, and a 22 pf sticker was found to be leaking, not short-circuited, not open, so it was soft-paned to the high frequency。
Change it, wave it up, screen it up。
This thing can't be seen in the naked eye, it can only be screened by equipment。
I've tried to get through with a "ding" with a watch binary tube, and i've tried to move to 200-m to see a leak, but it's time to rely on the oscillators。
But now cheap second-hand oscillators can sweep the lvds, $3,400, better than running a maintenance shop every day。
Behind each number on the voltage table are lines, components, contact, temperature, age fighting。
You say it's bad, it's probably just tired of rubbing, crushing, roasting, and waking up。
You said it was good. It could collapse in half a second. It's only half a mile away。
It's not about fixing television, it's about checking the same plate three times, three times over。
Today i changed seven times, measured 19 points, wrote two paper data, and finally found that the third needle in the screen slot was oxidized, scraped the ash, and the tv was lit。
