Yes, the IDE adapter could well be the cause, I remember at the time some types did cause problems. A great pity that the Hummy.org database was lost. 
Just for interest, I ended up with a very short cable (about 8cm) . Fitting the connectors on the appropriate side of the cable removes the need for the twist. All you have to do is make sure that the pin 1 of all the connectors line up with the red marked side of the cable.This makes it a much neater job and is probably less prone to electrical pick up.
