Any IIe hardware hackers?

["nonmaskable" <mikedl@comcast.net>]

Hi.  I'm trying to repair a IIe mainboard.  This is my first time
working with an Apple IIe, and the custom PAL, IOU, and MMU make fault
tracing difficult for me since I don't have any known good substitues.
>From looking with a scope, it looks as if the PAL is getting the main
three clock inputs (14M, 7M, and 3.5M) fine, but not putting out VID7M.
 Am I right in assuming that this means that the PAL is bad, or is
there another failure (e.g. the PAL control signals) that could explain
it?  Since replacement PALs aren't around it would mean the end of the
mainboard.

Thanks!