I have two Nikon camera flash units that are old but working fine.
SB-24
SB-20

Need help with

1) flash shoe pinout functions?
i.e. how to trigger manually through the falsh shoe?

2) how to open the units without damage to clean interior dust?

3) compatibility with Canon EOS Rebel series cameras?
i.e. will not damage either if attached/used?
will flash on camera shutter release. say in M or A mode?
will provide TTL capability?

If not compatible with Canon, then I will do the math and use a
wireless radio trigger to trip.

Speculations do not help.

I could not find newsgroups that are more specific. If you know of
any, please let me know.

Thanks!