Firstly this TV appears to have been made by Shenzen MTC (think that's the place) and its just re-badged as a "store brand" so it may be identical to other cheap brand TVs out there. Certainly looks like it has "generic" circuit boards inside.
The TV is only ~4 months old but Dick Smith has gone into receivership and aren't honouring warranties otherwise I'd just go down that route
Now the issue:
Upon being plugged in there is a very brief flash of light from the back light. The panel itself still works as images appear dimly using a torch.
based on this I'm assuming the fault is either in the back light assembly itself or in the PS board, because the panel itself still works and the tv responds to remote control etc.
Power board is : TV5001-ZC02-01 it appears to be a generic 50" Power supply board. schematic available at: http://www.go-gddq.com/upload/2015-0...0618093118.pdf
Schematic appears accurate except a few resistor values, generally feedback/setting pins on the ICs (I suspect these are because its driving a 55" screen/BLU not the 50" its intended for)
power board output/input voltages are :
12V: 12.6
5V: 5.4
5V stb: 5.4
PSON: can't remember if 3 or 5. but it clearly turns the board on.
BK/ON: ~3V
ADJ: ~3V (does this and BK/ON seem right? not sure if they are meant to be closer to 3.3 or 5v)
The back light unit itself consists of 2 separate circuits, each has 3 strips of 16 LEDs (48 total for each circuit, 96 in the entire assembly) as far as I can tell the LEDs within each circuit are all in series.
I've tested each LED with the "diode test" on my DMM and every LED illuminates dimly. Also on power up it appears that every LED flashes.
The PSU has 4 places for LED connectors, but only 2 have sockets soldered on, with each connected via a 0 ohm resistor to one of the disconnected sockets, this matches a possibility in the schematic so I assume it hasn't deviated too far from the design here.
measured the voltages at startup and the LED+ pins each jumped to ~115V (coinciding with the flash) measured between the pin and ground then dropped (while writing this I realized that the LED+ pins are a common rail so of course they will be the same. Will have to measure between the two LED pins rather than to ground as that may help isolate the problem). My DMM is just a cheap one and probably doesn't have the fastest response time, so may well have gone higher.
I cant see any burnt out chips or components. no fuses are blown. the TV screen keeps working and none of the voltage outputs turn off/change after the backlight does.
Anyone able to help me pinpoint where/what it could be? Or even give me somewhere to start troubleshooting.
I've attached some images of the PS board (assuming this is the most likely fault given what I've found so far). sorry for the poor quality, best I could do with my Phone camera. If better pictures are needed I'll try to borrow a decent camera.
The TV is only ~4 months old but Dick Smith has gone into receivership and aren't honouring warranties otherwise I'd just go down that route
Now the issue:
Upon being plugged in there is a very brief flash of light from the back light. The panel itself still works as images appear dimly using a torch.
based on this I'm assuming the fault is either in the back light assembly itself or in the PS board, because the panel itself still works and the tv responds to remote control etc.
Power board is : TV5001-ZC02-01 it appears to be a generic 50" Power supply board. schematic available at: http://www.go-gddq.com/upload/2015-0...0618093118.pdf
Schematic appears accurate except a few resistor values, generally feedback/setting pins on the ICs (I suspect these are because its driving a 55" screen/BLU not the 50" its intended for)
power board output/input voltages are :
12V: 12.6
5V: 5.4
5V stb: 5.4
PSON: can't remember if 3 or 5. but it clearly turns the board on.
BK/ON: ~3V
ADJ: ~3V (does this and BK/ON seem right? not sure if they are meant to be closer to 3.3 or 5v)
The back light unit itself consists of 2 separate circuits, each has 3 strips of 16 LEDs (48 total for each circuit, 96 in the entire assembly) as far as I can tell the LEDs within each circuit are all in series.
I've tested each LED with the "diode test" on my DMM and every LED illuminates dimly. Also on power up it appears that every LED flashes.
The PSU has 4 places for LED connectors, but only 2 have sockets soldered on, with each connected via a 0 ohm resistor to one of the disconnected sockets, this matches a possibility in the schematic so I assume it hasn't deviated too far from the design here.
measured the voltages at startup and the LED+ pins each jumped to ~115V (coinciding with the flash) measured between the pin and ground then dropped (while writing this I realized that the LED+ pins are a common rail so of course they will be the same. Will have to measure between the two LED pins rather than to ground as that may help isolate the problem). My DMM is just a cheap one and probably doesn't have the fastest response time, so may well have gone higher.
I cant see any burnt out chips or components. no fuses are blown. the TV screen keeps working and none of the voltage outputs turn off/change after the backlight does.
Anyone able to help me pinpoint where/what it could be? Or even give me somewhere to start troubleshooting.
I've attached some images of the PS board (assuming this is the most likely fault given what I've found so far). sorry for the poor quality, best I could do with my Phone camera. If better pictures are needed I'll try to borrow a decent camera.
Attached Files
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