jmunkki@kampi.hut.fi (Juri Munkki) (11/26/89)
I got a messsage from dtgcube!ed@uunet.UU.NET (Edward Jung): >Your wiring diagram is in error. There is a 0.01uF capacitor used as >Cf. This should be a 0.1uF capacitor. Moreover, the capacitor connected >to pin 5 is not strictly required. I got the two capacitors reversed. The center and right capacitor should change places. I haven't tried removing the capacitor. >Your instructions were a bit unclear on how you used a trimmer instead >of the matched 3k resistors (as Ra, Rb). We could figure it out, but I'm >not certain that other people can? A trimmer has three pins. The center pin connects to pin 7 of the 555. The other two pins connect to pins 7 and 8. I recommend using resistors. >Otherwise it seems to work pretty well. We get horizontal sync. lines >on the screen through a darkened lens -- I assume that this is because >the 400Hz signal is not a synchronized multiple of the scan rate. We are >able to reduce but not remove the visibility of these lines. The only problem I have had is that the lenses are not fast enough to darken in the vertical blanking time. The top third of the screen is visible to both lenses. I'm sorry if the error in the document has caused problems. My friends didn't have the time to verify my wiring and I knew that doing it myself wouldn't help. (Sometimes it's impossible to see errors that you have made yourself.) _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._ | Juri Munkki jmunkki@hut.fi jmunkki@fingate.bitnet I Want Ne | | Helsinki University of Technology Computing Centre My Own XT | ^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^