Re: new battlezone owner

>The other problem is the monitor. I'm an EE, so understand the basics of
>the electrolytic cap problems common to these monitors. I have no
>experience working on them, however. My game works perfectly, until it's
>been on a while. After a few games, the display balloons until the score
>and radar are no longer visible and the tank field is bigger.

        I'd say that it's the "classic HV diode" problem - I just fixed this on my
Ast. Deluxe. There's a rectifier diode in the HV cage - when it starts to go out,
the voltage lost across it increases as it heats up, causing a "blooming" effect
on your display.

        You can check if this is the case by running your game with the HV cage
open, waiting until the problem appears, then spraying the diode with "freeze spray"
(available at most electronic stores for a coupla bucks). If the display shrinks
back down, then you know that it's your HV diode.

        If you need to replace it - I think the SK7333 (available from
www.mouser.com) is the consensus replacement part. The replacement is bigger, so
it's kind of a pain to install it. You need to solder the replacement directly to the
wires, then coat the wires with RTV silicone to prevent electricity from arcing to
the sides of the HV cage.

        The usual caveats about discharging your monitor tube before screwing around
with the HV apply here as well. And make sure you install the diode the right way
(as I recall, the part with the band on it connects to the red wire). Welcome to the
hobby ;)

        Feel free to drop me a line if you have any other questions about doing
the HV replacement - I would never have gotten mine installed without advice from
Chris Candreva and others on the list.

                        Drew
Received on Thu Feb 11 18:59:52 1999