I eventually got around to combining my basic digital camera and a stereo
microscope.
As a test i decided to try capturing the crack in a known bad video head as
a good test of
resolution, focus and exposure for a small black ceramic surface.
http://www.diversed.fsnet.co.uk/vcr_head.htm
The crack is just visible by eye through the microscope, but not in the
lower of the 2 pics, vertically at the narrowest central
point of the black horizontal section that is in focus, a secondary small
horizontal crack at that same point
is visible in the pic just to the top right of this necked central area.
Assuming it is not a problem with lack of resolution , only 2Mp, any tips
for such demanding situation ?
The camera is in place of one of the eyepieces removed and a pre-focus torch
bulb shone down the other eyepiece to get the illumination level up, as well
as some overall illumination. I broke into the camera to be able to wire in
a remote switch for "shutter release" to avoid camera shake. There is some
manual exposure control on the camera but I've not tried that option as yet,
relying on auto exposure.

Incidently for the electronics bods I assume there is no filler /fudge for
such a cracked head.
I seem to remember the wire for such heads has to be gold and not copper to
be ductile enough to form such coils, is that still the case?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs
http://home.graffiti.net/diverse:graffiti.net/