Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!swrinde!cs.utexas.edu!usc!brutus.cs.uiuc.edu!uakari.primate.wisc.edu!uwm.edu!mailrus!ncar!tank!eecae!cps3xx!usenet
From: usenet@cps3xx.UUCP (Usenet file owner)
Newsgroups: sci.electronics
Subject: Need help fixing a vector arcade game display!
Keywords: CRT  High Voltage  Arcade Game  Old
Message-ID: <5390@cps3xx.UUCP>
Date: 14 Nov 89 21:17:42 GMT
References: <938@swbatl.UUCP>
Reply-To: beyer@frith.UUCP (Don W Beyer)
Distribution: usa
Organization: Engineering, Michigan State University, E. Lansing
Lines: 31


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