Hi everyone,
Thanks for the help. I bought some fuses and the guy at the electronics shop said try to replace the fuse one time and see what happens, but only once. So that's what I did.... I placed a 4A/125V fast-blow fuse and blow it did!
The minute I plugged in the TV I saw the lights flicker and I think that was basically when the magic smoke was released from the fuse. Obviously these TV's are "always on" the minute you plug in they have a standby power draw to power the soft-touch buttons on the front and also the circuit listening for the remote control.
Ok, so now it is on to a real detective and repair job. First thing is I removed the power supply board from the back of the TV so I can easily work on it. I'd like to somewhat figure out the schematics here so I can understand what is going on. From what I can gather from the board (you can look at the pictures and let me know if this is correct)....
1. Mains enters in LIVE/NEUTRAL and the LIVE immediately passes through the fuse in series
2. There is a resistor across the other side of the fuse and neutral... Brown/Red/Green/Gold = 1.2Mohms
- I tested it, measures 1.08Mohm. I figured if the resistor shorted it would blow the fuse. But it is ok. I don't think resistors fail that way anyways... they would if anything break completely and go to infinite resistance.
3. Next also in parallel with the resistor (crossing from other end of fuse to neutral) is a blue cap-like flat component with part number SVR 10D 471K SEC C. There is a "Z" written on the board under it. I assume this is a Varistor. Reading up on it looks like it is a surge protector, clamping the voltage down if there is a splike.
4. Next, also in parallel with the resistor and the varistor is that large blue box-like component with 470nK275V X2 PCX2 337 MK written on it. Google reveals it is a Pilkor component... Interference suppression film cap. Reading up on it, sounds like it EMI/RFI suppression to reduce noise/interference and spikes as well.
Anyways, none of these devices are shorted.... so if the resistor, varistor or cap were shorted that would immediately short the LIVE and NEUTRAL through the fuse.
So continuing on.... I looked up the next part and guess what.... A service manual turned up!
HERE IT IS:
http://diagramasde.com/diagramas/otros2/PL12.0%20EN%20040812.pdfThe manual says to check each component on the primary side for a short circuit, and each rectifying circuit on the secondary for a short. So I took out the multimeter and placed it across all the diodes (in both directions) using continuity tester and I had a couple of the diodes test continuous. But looking closely at the circuit, I noticed one of the diodes that was continuous was in parallel with a resistor valued at only about 0.68 ohm.... so I can't test that diode unless I remove it from the circuit. The other one is a bit more complex.
I've attached the power supply block diagram from the manual I linked above....
Any guidance would be appreciated. I think the next step is to begin desoldering diodes and replacing caps? I don't know which direction to go first here.