usenet@cps3xx.UUCP (Usenet file owner) (11/15/89)
A "friend of mine" (no really!) has a Space Wars video game which is slightly defective, and has enlisted my help to bring it back up to mint (1977!) condition. The problems lie in the video section. Specifically, the VectorBeam (tm) vector display. The display is very dim and can only be viewed in a totally dark environ. The yoke amp is fine, as everything is in the right place...just very dim. Judging by the schematics, the flyback and tripler that produce the HV for the CRT look pretty straightforward. I assume that anyone that has any TV service background would probably view this as a trivial problem. I know that there is SOME high voltage, as I have a discharge tool that I use before touching anything in the HV section, and it makes Happy static sounds after the unit has been powered off. The question is, what would a TV serviceman do if given this dim display problem? I have very little experience with HV and CRT drive electronics, so I have not really made any progress towards reparing the display. I have schematics of the video section, and would be willing to send them out to anyone who would in return offer repair advice. Or, if you or "a friend" happen to have a VectorBeam (tm) video display unit (B&W) from another, ex-video game, and would be willing to part with it, send me mail at beyer@frith.msu.edu or lemense@msupa.msu.edu I'm lost in a sea of High Voltage! Tom LeMense
cook@stout.ucar.edu (Forrest Cook) (11/16/89)
In article <5390@cps3xx.UUCP> beyer@frith.UUCP (Don W Beyer) writes: > >A "friend of mine" (no really!) has a Space Wars video game which is >slightly defective... >....The display is very >dim and can only be viewed in a totally dark environ. The yoke amp is >fine, as everything is in the right place...just very dim. Sounds like an old picture tube to me. You have several choices: 1: (the best, the most expensive) buy another picture tube and replace the old one. Be sure to discharge the second anode connection carefully with a long grounded screwdriver, the shock can knock you across the room, I KNOW 8*[ 2: (second best) get the old tube rebuilt, the part that wears out is the gun cathode, The rebuilt tube usually works as well as a new one but costs less, if you can find someone who rebuilds tubes. 3: (third best) find an old picture tube brightener transformer that increases the voltage to the fillament. This is cheap and should last for a while. 4: (fourth best) get the tube rejuvinated at your local tv repair shop. You might need to have a pinout of the tube before this can be done. The tube may not be standard. Hope that helps. ^ ^ Forrest Cook - Beware of programmers who carry screwdrivers - LB /|\ /|\ cook@stout.ucar.edu (The preceeding was all my OPINION) /|\ /|\ {husc6|rutgers|ames|gatech}!ncar!stout!cook /|\ /|\ {uunet|ucbvax|allegra|cbosgd}!nbires!ncar!stout!cook
myers@hpfcdj.HP.COM (Bob Myers) (11/17/89)
re: I'm lost in a sea of High Voltage!
The high voltage may be fine, and the display still unacceptably dim.
Check the screen grid voltages for a start, although where you're going to
find a listing of the "nominal" voltages is beyond me. Considering the
use that these arcade games get, though, it's entirely possible that the
CRT - specifically, the cathode in the electron gun - has gone to the
Big Photon Factory in the Sky, and a tube replacement would be your only
hope. Good luck!
Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not
Ft. Collins, Colorado | those of my employer or any other
myers%hpfcla@hplabs.hp.com | sentient life-form on this planet.