I found this site due to a google match of the PE0702 (V28A000962A1) power supply board on this post: https://www.badcaps.net/forum/showthread.php?t=15787
That board is common to the 46xv648u model of Toshiba TV and I'm seeing the same symptoms as described in the other thread. Unfortunately the problem with my board must be something different and further 'downstream' since the issues described there all check out OK on my board.
I have plenty of electronics experience, but I'm used to having the luxury of schematics. I've searched plenty, but no schematics or service manuals are publicly available for this board.
I recently fixed my sister's Toshiba TV which had a bad backlight inverter board, but for that I was able to find a service manual with troubleshooting flow charts, PCB diagrams, schematics, etc. Boy, was that helpful! But this time I'm running rather blind. I say 'rather' because some of the connectors between the power supply board and the main video board have the same reference designators and very similar pinouts and signal names as my sister's TV had. If the troubleshooting guide for my sister's TV is applicable, it points to the power supply board as bad and needing to be replaced.
It is hard to say for sure, but I believe that the issue is related to the AC_DET signal - which I take to mean "AC power detection" - being low. It could be an active low signal, but for my sister's TV I believe that signal was high when the TV was plugged in.
All of the pictures from the thread I referenced above match my board and all of the IC's described there match as well. My A6169 SMPS seems fine. The voltages between the points mentioned in posts #26 - #28 are all 120V on my board. My R850 is about 2 ohms (not Mohms) as it should be, and the relays (one 5V & the other 12V) seem OK. Other problems described there involve voltage regulators on the video board, but I think my TV is failing somewhere in between - I'm not even getting input voltage to those regulators.
Replacement power supply boards have been difficult to find - everyone's out of stock - and the few I have found want ~$200 for them. I don't want to spend that kind of money unless I'm sure it will fix the problem. I don't have much history of what happened to this TV, just that it 'stopped working', so I'm concerned that the root cause could be further downstream and even if I fix the power supply, it may toast again due to something else being bad.
Of course I've tried all the simple things - all the fuses I can find measure good, none of the caps look like they're bad, no components have fried or popped, and none of the IC's get hot (most of them probably aren't powered at all). The only sign of life when I plug in the power is the 5V relay clicks on after a short delay. As expected, it clicks off after a short delay when the set is unplugged, too.
Any suggestions on how to narrow down the culprit or what to check/try next would be appreciated.
That board is common to the 46xv648u model of Toshiba TV and I'm seeing the same symptoms as described in the other thread. Unfortunately the problem with my board must be something different and further 'downstream' since the issues described there all check out OK on my board.
I have plenty of electronics experience, but I'm used to having the luxury of schematics. I've searched plenty, but no schematics or service manuals are publicly available for this board.
I recently fixed my sister's Toshiba TV which had a bad backlight inverter board, but for that I was able to find a service manual with troubleshooting flow charts, PCB diagrams, schematics, etc. Boy, was that helpful! But this time I'm running rather blind. I say 'rather' because some of the connectors between the power supply board and the main video board have the same reference designators and very similar pinouts and signal names as my sister's TV had. If the troubleshooting guide for my sister's TV is applicable, it points to the power supply board as bad and needing to be replaced.
It is hard to say for sure, but I believe that the issue is related to the AC_DET signal - which I take to mean "AC power detection" - being low. It could be an active low signal, but for my sister's TV I believe that signal was high when the TV was plugged in.
All of the pictures from the thread I referenced above match my board and all of the IC's described there match as well. My A6169 SMPS seems fine. The voltages between the points mentioned in posts #26 - #28 are all 120V on my board. My R850 is about 2 ohms (not Mohms) as it should be, and the relays (one 5V & the other 12V) seem OK. Other problems described there involve voltage regulators on the video board, but I think my TV is failing somewhere in between - I'm not even getting input voltage to those regulators.
Replacement power supply boards have been difficult to find - everyone's out of stock - and the few I have found want ~$200 for them. I don't want to spend that kind of money unless I'm sure it will fix the problem. I don't have much history of what happened to this TV, just that it 'stopped working', so I'm concerned that the root cause could be further downstream and even if I fix the power supply, it may toast again due to something else being bad.
Of course I've tried all the simple things - all the fuses I can find measure good, none of the caps look like they're bad, no components have fried or popped, and none of the IC's get hot (most of them probably aren't powered at all). The only sign of life when I plug in the power is the 5V relay clicks on after a short delay. As expected, it clicks off after a short delay when the set is unplugged, too.
Any suggestions on how to narrow down the culprit or what to check/try next would be appreciated.
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