I have a modded V4 that was working fine for about a year. The guy brought it back saying he needed a new laser.
I tried to replace it with a 400c, it takes 10-15sec to boot originals and will not bootbackups
I found a new 400b and it does the same thing.
I tried adjusting the cog and the (cant remember the name) set screw but it doesn't seem to make a difference.
If you have tryed with your osiliscope and can find any thing that works 100% cog ajustment screw pots and all.. Ask him if it had ben droped ..Ther is a good chance that the LA/BA are on ther last leg..