Lisa 2 (Mac XL) Screen showing multiple images

Just for a change, I don't want to talk about my ICT 1301. We are having a clear out at work and I'm taking various bit home (like an H.P. DraftMaster MX+ A0/E sized plotter as well as a little 7475A A3/B size plotter). There is also a Graphtec MP3200 flatbed plotter. It seems to be all there except the plug-in power supply which supplies 7v and 24v DC through an unusual 3 pin plug. I don't suppose anyone has a spare power supply, or even just the socket ? (or receptacle for US readers) I've taken my old Lisa 2 home after a few years disuse and tried it out. It currently has MacWorks installed on the hard disc and it booted fine but the screen has a problem, it shows three smudged menu bars equally spaced down the screen and it also has fairly bright fly back lines at about 30 degree angles. I have the official spares kit for it but never went on the training course as I programmed them, someone else who has now left the company, repaired them. Is this likely to be a minor logic fault in the video generation circuitry, presumably on the I/O board, or there is a small board in the spares kit which handles the high tension for the screen, is it more likely to be that? How do I get at the HT board? Do I have to remove the four screws at the front of the CRT? It seems unlikely Apple would have made engineers do that but how else can I get into the HT enclosure? Roger Holmes