Hello!
I have this old JVC LT-42TG30J TV with a flashing blue light. It does not turn on, but weirdly, if I leave the power switch on, the backlight of the TV randomly comes on though the blue light continues to flash and I can't bring up something like a volume control, which makes me think that the backlight just randomly turns on even if the system isn't. I can hear this mechanical hum from the inverter board as well. It will turn off and on itself randomly after that. Weird. The first time it happened it scared me to death lmao.
My first test was to see if the power supply was OK. It has a 17PW26-5 type PSU, which has no schematics D: Though the older revision (17PW26-4) does and the power connector is similar.
Here are the results:
12_V1 OK @ 11.80
5V STANDBY OK @ 5v sharp
3.3V OK @ 3.3v
VCC_3V3_ON OK @ 3.3v
24VA OK @ 24v
PIN_11 OK @ 11.80V
PIN_13 OK @ 3v
PIN_15 OK @ 3.3v
PIN_17-21 OK @ 5v
PIN 23 OK @ 24v
ST_BY is... weird. It's at 0.00v volts but when I cut power to the board it goes 3.3v. It could be normal behaviour though...
SW_SWITCH... I'm unsure of what that is. It fluctuates between 8.02v and 9.35v. Something tells me that this isn't normal. Maybe this is the line that turns on the backlight? The inverter board is connected to the power supply, so the logic board must send a signal through somewhere to turn it on, which also makes me believe that the logic board is the problem.
What do you think? I say bad logic board... especially because of the random backlight on thing... though I didn't test everything on the PSU. Some lines like PIN_27 KEY I'm unsure of what it does and PIN_1-9 seems to be nothing as well as BLK_ON/OFF (wtf is that?) which is at 0.4 volts constantly.
I just don't want to get a logic board only to find out that nothing is wrong with it
Here are some pictures if you need 'em. Both boards look free of capacitor corrosion and bulging.
BTW love the retro design of the forum. Please don't ever change it.
I have this old JVC LT-42TG30J TV with a flashing blue light. It does not turn on, but weirdly, if I leave the power switch on, the backlight of the TV randomly comes on though the blue light continues to flash and I can't bring up something like a volume control, which makes me think that the backlight just randomly turns on even if the system isn't. I can hear this mechanical hum from the inverter board as well. It will turn off and on itself randomly after that. Weird. The first time it happened it scared me to death lmao.
My first test was to see if the power supply was OK. It has a 17PW26-5 type PSU, which has no schematics D: Though the older revision (17PW26-4) does and the power connector is similar.
Here are the results:
12_V1 OK @ 11.80
5V STANDBY OK @ 5v sharp
3.3V OK @ 3.3v
VCC_3V3_ON OK @ 3.3v
24VA OK @ 24v
PIN_11 OK @ 11.80V
PIN_13 OK @ 3v
PIN_15 OK @ 3.3v
PIN_17-21 OK @ 5v
PIN 23 OK @ 24v
ST_BY is... weird. It's at 0.00v volts but when I cut power to the board it goes 3.3v. It could be normal behaviour though...
SW_SWITCH... I'm unsure of what that is. It fluctuates between 8.02v and 9.35v. Something tells me that this isn't normal. Maybe this is the line that turns on the backlight? The inverter board is connected to the power supply, so the logic board must send a signal through somewhere to turn it on, which also makes me believe that the logic board is the problem.
What do you think? I say bad logic board... especially because of the random backlight on thing... though I didn't test everything on the PSU. Some lines like PIN_27 KEY I'm unsure of what it does and PIN_1-9 seems to be nothing as well as BLK_ON/OFF (wtf is that?) which is at 0.4 volts constantly.
I just don't want to get a logic board only to find out that nothing is wrong with it
Here are some pictures if you need 'em. Both boards look free of capacitor corrosion and bulging.
BTW love the retro design of the forum. Please don't ever change it.
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