TRS-80 Model III

I am trying to get a TRS-80 Model III working. When I turn it on the disk drive spins for a while looking for a disk I presume. All I get on the screen are wispish diagonal lines as if the horizontal hold is all whacked. I managed to unstick one of the video adjustment knobs on the left underside but all it does is affect the brightness level. The other one requires a screwdriver to move at all (shimmying it up and down) and does not seem to affect the display. I haven't opened it yet to see what adjustments are inside. I'd rather not, but there don't seem to be any adjustment pots accessible from outside the case. What's weird is that I have access to a bunch of TRS-80 Model 3's here at the ACCRC and pretty much all of the ones I have played with so far are basically "dead" in this manner. The one I'm working on just came in today and is in the same state. Also, the video knobs on the left underside are all stuck on everyone I've tried to get working. What is the deal with that? Do they get rusted over time or something? Very annoying. The fact that the disk drive spins up when I turn it on is a good sign I hope. Any help on this would be appreciated. I know next to zero about the TRS-80 series. Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org * Old computing resources for business and academia at www.VintageTech.com *