Date: Thu, 9 Feb 2006 16:18:51 +0000 (GMT) To: techno-fandom@techno-fandom.org From: hobbit@avian.org (*Hobbit*) Subject: static zing So I'm doing lights for yet another Washington St Players gig, and was down there last night for more tech-week rehearsal. There had been a couple of prior complaints about their board [a Lep LP1536, like we had at Arisia] suddenly making everything go dark once or twice. It had been working fine for me, up until last night. As I started checking things and tweaking a couple of subs and running down to improve some focus issues, it started losing its little mind on me. Freezing, rebooting, not following faders, that sort of thing. Now, I'd already found one problem, in that the power connector where the wall-wart goes in is flakey -- if the plug is pushed all the way in and then the wire wiggled the right way, the board loses power. But this was fixed by pulling the plug slightly out, and then it's stable. This was a new problem, caused by no physical movement that I could discern or reproduce by whacking the board. Like I'd get up from the chair, slide past the end of the table that I had sort of wedged in next to the tech closet so I can also reach the house-light dimmers, and start reaching back toward a slider, and it would freak out. That was the key to it. I slid past the table. One of those newer white-plastic-top tables that the Town Hall had bought a mess of, which are nice and light and easy to throw around ... but which I had noticed a while back definitely made my arm-hairs rise as I sat down at it and put my hands up on the board. And here I was brushing my cotton-clad legs along one edge as I squeezed out of my little hole past the thing. I tried a good long slide a couple more times, and could reliably make the board freeze or go dark without actually touching it or anything else. This built up a big-ass charge, which eventually jumped out through some piece of the board and then who knows where else on its way. It was also colder and drier last night than it had been, and my arm hairs were definitely telling me that. Well, this thing has no real ground -- a two-prong wall-wart plugged into questionable electrics [and I had already previously rejected an extension cord offered from the WSP stock that had its ground pin chopped off who-knows-when]. So I had a ground up to the strip but not actually to the board. I figured the board at the very least needed a hard case ground to try and alleviate this static business. The case is painted all over, with no discernable bare-metal ground point anywhere on the back. I had no real spare wire to speak of, or alligator clips, or anything like that. So I backed off a couple of case screws, shaved off the paint along one or two edges, and jammed the loop of a safety cable into the slot thus opened up and retightened the screw so it had a solid connection to the case. The other end of the safety went through a rather idiotic kludge of a couple of edison/stagepin adapters crocked together in a way so I could clip the safety to a grounded piece of metal derived from the outlet strip. It definitely helped. If I rubbed the table a lot I could still get the board to freak, but it was much more resistant. The other half of the answer is to flush this table and go with an older particle- board type, that might still have just a little WATER content. But this should be a WARNING to all that this new breed of table is a serious static magnet, and may cause all kinds of hellacious, sporadic problems in cold weather. We were fortunate at Arisia that it was somewhat warmer and wet and static wasn't really an issue this year, but for future reference and noting the fact that the BPPH [and probably many, many other hotels] are buying these new plastic-top tables hannoverfist, I bet that people working on productions of all sorts will see many more odd equipment problems. Bottom line: if you're forced to use these tables, bring some sort of anti-static mats and make sure ALL gear is hard-grounded. Maybe there's a new market here... because I don't think the people making these tables are taking any of this into account. And the idiots supplying ungrounded wall-warts for critical-path gear certainly aren't. _H*