So i spent a good amount of money and time doing things i thought would solve the issue before decided to ask here (maybe that was wrong, but thats what I did, and its not messed up more than it already was)
LCD TV: Hitachi 32LD8800TA2 NA
PSU board: PK101V0360I
This old TV shuts down randomly (and after a period of watching, if you change the channel), after that, it drops dead without any lights on, and if you power it off and on again, the power light turns green, you expect it to power on but the light goes off and its dead again. After 10 min, (sometimes half an hour) power it on again and it behaves like nothing happened. this also happens if you normally turn off the TV after watching for sometime and then turn it on immediately.
Decided to troubleshoot and I found some pins of a chip in the primary circuit of the PSU burnt. its the L6598 chip and the pins burnt were 15 16 (and maybe 14)
Immediately ordered a new PSU (without confirming the problem was primarily there, sigh). the main board looks normal. the replacement board arrived dead, though. looks perfect but doesnt power on. checked fuses, transformers, inductors, with a multimeter. and i'm having a tough time getting a replacement. I still have the new board untouched. mental note to self: (NEVER order from "narayanitech" online store in India
(thats a useful advice to others too)
so I took the chip (L6598) off from the previous board (the chip was blackened at the base), and soldered in a new one. read on some forums and changed two MOSFETs connected to it too.
problem persists.
Didnt use it much after the testing for fear of blowing my new components. I changed all caps of the primary circuit of psu and some from the secondary circuit (couldnt find exact or compatible rated caps for some caps in secondary area, so didnt touch them)
problem persists.
Interestingly, I can watch three hours continuous if i step down the voltage supplied to TV with a manual voltage stabilizer and keep it at 150V. I havent checked beyond that time, but in those three hours, i can change channels or inputs and turn the TV off and on and it doesn't misbehave.
attached is my service manual with arrows on the changed MOSFETs and L6598 (psu schematic on page 32). i did the comments with foxit PDF, if you can't see it.
So, now i think i need help seriously.
any ideas what may cause this behavior? (or, importantly, what may solve it?)
LCD TV: Hitachi 32LD8800TA2 NA
PSU board: PK101V0360I
This old TV shuts down randomly (and after a period of watching, if you change the channel), after that, it drops dead without any lights on, and if you power it off and on again, the power light turns green, you expect it to power on but the light goes off and its dead again. After 10 min, (sometimes half an hour) power it on again and it behaves like nothing happened. this also happens if you normally turn off the TV after watching for sometime and then turn it on immediately.
Decided to troubleshoot and I found some pins of a chip in the primary circuit of the PSU burnt. its the L6598 chip and the pins burnt were 15 16 (and maybe 14)
Immediately ordered a new PSU (without confirming the problem was primarily there, sigh). the main board looks normal. the replacement board arrived dead, though. looks perfect but doesnt power on. checked fuses, transformers, inductors, with a multimeter. and i'm having a tough time getting a replacement. I still have the new board untouched. mental note to self: (NEVER order from "narayanitech" online store in India
(thats a useful advice to others too)
so I took the chip (L6598) off from the previous board (the chip was blackened at the base), and soldered in a new one. read on some forums and changed two MOSFETs connected to it too.
problem persists.
Didnt use it much after the testing for fear of blowing my new components. I changed all caps of the primary circuit of psu and some from the secondary circuit (couldnt find exact or compatible rated caps for some caps in secondary area, so didnt touch them)
problem persists.
Interestingly, I can watch three hours continuous if i step down the voltage supplied to TV with a manual voltage stabilizer and keep it at 150V. I havent checked beyond that time, but in those three hours, i can change channels or inputs and turn the TV off and on and it doesn't misbehave.
attached is my service manual with arrows on the changed MOSFETs and L6598 (psu schematic on page 32). i did the comments with foxit PDF, if you can't see it.
So, now i think i need help seriously.
any ideas what may cause this behavior? (or, importantly, what may solve it?)