As I wrote that post, I searched my Chrome bookmarks for it, but alas, it seems I was mistaken, apparently I did not keep it for future reference...
What I do remember is that it's really just about tuning a variable in the service menu. If someone needs it, I can look into the service menu of my PVM and find the variable I changed. Maybe I'll do it this weekend if I have the time (and if I remember how to access the bloody service menu ifself).
In any case it's a pretty cool workaround, as it saved me from having to change capacitors on my PVM, which is definitely not something I'd be able to do myself. The lines are still visible in 16:9 mode though, but I never use that mode anyway.