IBM 5154 smearing

A few weeks ago I rescued a 6Mhz IBM AT in an unusual rack mount case with a Plexiglass cover. I don't know how it got in that condition or how anybody permitted it, being as it was not shielded. But I digress .. (It is marvellous .. like the original case mod!) It had a 5154 with it that displayed output, but the output looked as though it was 'smearing' to the right. This made text look goofy. The problem was more apparent in graphics modes. A different 5154 or worked on the machine so it is definitely the monitor, not the EGA card. I'm a monitor novice. I know these things pack a punch, so I have a healthy respect for them. Are there any simple checks to make? (I have the Sams guides for the 5151 and the 5153, but not the 5154 so I'm kind of in the dark.) The machine also came with a 5151 that doesn't work at all. I don't even think it is getting power. For that one I can refer to the Sams guide. As for the rest of the machine, it was fine except for the full height hard disk. The hard disk would start spinning, but it sounded as though it was making metal shavings - I don't think there is any hope for it, so I replaced it with an modern IDE drive and controller. The machine has 1152KB, EGA with daughterboard, monochrome card, IBM 5250 emulation card, IBM token ring card, original BIOS and a single 1.2MB floppy drive.