TFT Monitor output is blurry and weird looking - but OSD works fine
I'm guessing a bad pin - one of the syncs (either horizontal or vertical).  According to pinouts.ru this could be either pin 10,12, or 13 (sync ground, horizontal or vertical sync).  If you can swap cables on your monitor try that.  If you can and that doesn't help, it's the connector on the monitor.  You could try to replace it - aim a heat gun at the connector and pull it when all the solder melts or use a hot air rework station or a solder wick, then replace it.  You can buy right angle HD-15 connectors like this one on Digikey or elsewhere.  Remember - it's a high-density 15 pin D-sub connector, female, through-hole and probably right-angle.  Should be cheap if that's the issue.  Good luck!