Hey, in case anyone hits this page, like me, via Google, here is some information transcribed from the JVC TV manual:

1) Make sure the remote's TV/CATV switch is set to TV.
2) Press the VCR POWER and RETURN+ buttons simultaneously, then release.
3) Use the 10 keypad to enter the code, then hit RETURN+.

If the VCR does not respond:
1) Press VCR POWER and RETURN+ buttons simultaneously then release.
2) Press VCR POWER repeatedly until the VCR responds.
3) When the VCR responds to the command press RETURN+.

The codes listed for Sony brand VCRs are: 011, 032, 033, 034, 035.

Hope this helps someone, someday, though that is increasingly unlikely, isn't it?