If anyone is in need of a manual for the Merc-O-Tronic 9800 tester I’ve just scanned mine and uploaded it to google drive. Don’t know how to upload it here so it can be downloaded below.
That is the model 98 manual that requires a 110v line cord for condenser testing. The manual I uploaded is for the newer 9800 model which runs purely on battery and can do cdi coils without needing an adapter like the 98. They both may contain identical information just thought i’d upload the other since the 9800 model is harder to obtain compared to the standard 98.