I did some more crimping with the HT-225D from Amazon last night on the GI connectors on a 90s Bally/Williams game and did not quite have a good experience. I'm thinking about returning the crimp and trying to find another.
I think those wires are 22 gauge -- they're definitely small. I was using the 18-22 gauge jaw of the crimp, and neither the crimp on the wire nor the insulation was as good as I hoped. After crimping as tight as I possibly could, you could generally wiggle the connector and it would slide up down a little bit on both the wire and insulation. Some terminals pulled right off...
I don't think I'm doing anything wrong, I'm thinking that the crimp just isn't quite the right tool for the job. I tried crimping one pin with the smaller jaw (24-30 gauge or something...), but the squeeze was so tight that the terminal got stuck in the crimp and needed to be pried out.
Terminals are .156" Trifurcon Crimp Terminals from Pinball Life. I don't think they're to blame at all.
Also, because it's worth mentioning, yes I have spent hours reading and studying http://www.pinrepair.com/connect/
Anyone have a different experience with this crimp?