While we're talking about Lisas

My Lisa 2 (vanilla one, 1.2A PSU) has developed a habit of turning the screen off while she's running. In fact it's now permanently off which is annoying to say the least. Some of you may have experienced this before so here are the symptoms; System working fine (at the time running MacWorks 1.0), screen goes dim as per screensaver then blinks off like I'd hit the power button. It eventually comes back on after leaving it powered down for a couple of hours. James at Sigma Seven Systems said he thought he remembered there was a serial port bug in MW1.0 that caused the screen to go off sometimes so I left it at that. I've now got myself a ProFile so I was intending on installing LisaOS 3.1, but when she was powered up for the first time since maybe mid-may the screen came on briefly then blinked off again as it did before; since then it's only come back on once for around 10 minutes. While all this is going on the machine keeps running normally. If I power up I hear the self test passing, if I've got the first OS disk in (or MacWorks boot disk) it will actually boot, if I've got a standard composite monitor connected I can see things happening so I know the machine itself is fine....... Anyone else seen this? I've got another video card and screen coming over but it won't be here till the end of august; to say I'm champing at the bit would be an understatement :) cheers!