C-Sync and 5V Bridged...

[CGQuarterly]

I finally got around to RGB modding a little white PCE that I've had forever.  Completed the work, and it isn't working properly.  Did some troubleshooting and found that the C-Sync line is bridged with 5V, which is pretty consistent with what I saw on the screen.  I checked my solder points and they are definitely not shorted.  Pins inside the expansion port aren't bent.  Any ideas?

[mickcris]

are you positive they are not shorted.  the pins on the expansion port are right next to each other.  post some pictures if you can of your install.

[wilykat]

Check the 6280 chip if you soldered directly to it, you may have missed a solder blob.

[Keith Courage]

If you are getting sync from the hu6260 chip itself or the exp port then yes it is almost 5v. Should read around 4.5V

If you are having sync issues then try composite video for sync instead.

[CGQuarterly]

After I posted this, I used a continuity tester to check the 5V line and all of the other pins on the expansion port, and most of them beeped.  Right after that one of the ribbon cables attaching the PCB on the underside of the lid to the main PCB completely popped off (I suppose from being repeatedly bent back and forth from all of the opening and closing.)  So that may somehow have something to do with something.  I am going to get some IDE cable and replace both of those ribbon cables, and then see what's up with the system.