Hi everyone, I've been troubleshooting my 20" Sony Trinitron (KV-20FV12) CRT after it failed to show a picture. The standby LED is blinking 4 times, which according to the service manual is a failed vertical deflection via the self-diagnostic check during power up.
After getting the TV checked out by a technician and doing research on my own. The most obvious first step was to replace the IC502. I've done so with an exact NOS replacement with no luck. I've read a few suggestions to make sure the 12V supply to pin 2, but that voltage check would seem misleading? It seems if the self diagnostic fails, the IC502 will get a supply voltage? I checked anyway and the multimeter reads no voltage.
Throughout this process, I've been looking at the TV's schematics (attached the service manual) to try and better understand where the failure could be coming from, but with my limited understanding of circuit boards, it's incredibly difficult to follow; especially when the current splits in different directions. Near the IC502, I've spot checked a few of the diodes and resistors, to make sure they are reading per spec, but I've exhausted my skills and understanding of the issue.
If someone is willing to take a look at the schematics and guide me through troubleshooting the vertical circuit, or suggest a fresh starting point, it would be hugely appreciated! Hopefully this troubleshooting process and resolution will be helpful to others, and I can keep this TV alive.
After getting the TV checked out by a technician and doing research on my own. The most obvious first step was to replace the IC502. I've done so with an exact NOS replacement with no luck. I've read a few suggestions to make sure the 12V supply to pin 2, but that voltage check would seem misleading? It seems if the self diagnostic fails, the IC502 will get a supply voltage? I checked anyway and the multimeter reads no voltage.
Throughout this process, I've been looking at the TV's schematics (attached the service manual) to try and better understand where the failure could be coming from, but with my limited understanding of circuit boards, it's incredibly difficult to follow; especially when the current splits in different directions. Near the IC502, I've spot checked a few of the diodes and resistors, to make sure they are reading per spec, but I've exhausted my skills and understanding of the issue.
If someone is willing to take a look at the schematics and guide me through troubleshooting the vertical circuit, or suggest a fresh starting point, it would be hugely appreciated! Hopefully this troubleshooting process and resolution will be helpful to others, and I can keep this TV alive.
Comment