lazyone
New Member
Hi,
I've been trying to repair a Sony PVM-14M4E which does not show any image on 50Hz inputs (any input type or port). I works perfectly fine with 60Hz input.
I bought a cheap oscilloscope to try and diagnose further but I'm stuck.
I see that the UPC1377C stops producing the V-Blank signal (pins 12 and 13) when 50Hz input is present, it outputs a constant voltage instead of the expected 50Hz wave.
Could it be that the IC is defective or is there another signal that the IC is expecting that's missing?
On 60Hz signal I can measure a clear 60Hz wave on pins 12 to 15 + 18 to 20, on 50Hz signal all the pins output a 50Hz wave except for 12 and 13 for v-blank.
Thanks!
I've been trying to repair a Sony PVM-14M4E which does not show any image on 50Hz inputs (any input type or port). I works perfectly fine with 60Hz input.
I bought a cheap oscilloscope to try and diagnose further but I'm stuck.
I see that the UPC1377C stops producing the V-Blank signal (pins 12 and 13) when 50Hz input is present, it outputs a constant voltage instead of the expected 50Hz wave.
Could it be that the IC is defective or is there another signal that the IC is expecting that's missing?
On 60Hz signal I can measure a clear 60Hz wave on pins 12 to 15 + 18 to 20, on 50Hz signal all the pins output a 50Hz wave except for 12 and 13 for v-blank.
Thanks!
