Sounds that way… I’d still be looking at the cable… Sometimes a meter won’t detect dodgy solder joints. Try measuring resistance on each cable before you splash out on a new LCD. If some have a very high resistance compared to the others, you might have a dry joint.
I don’t think it’s a cable issue. If a character LCD is showing things that are definitely not characters, it’s probably broken, unless it’s being weird because of insufficient current… there’s no way that even garbage input can make it display per-pixel patterns.
Me neither, very unlikely… but worth the two minutes of checking before spending $$ on a new LCD,
(it just occurred to me, that you’d also throw out the old supposedly-dead one, after soldering in the new one - and fixing the cable at the same time… double bummer!)
because…
there’s no way that even garbage input can make it display per-pixel patterns.