Re: space wars repaired saga

• From: "Mark" <mhorcher@xxxxxxxx>
• Date: 25 Jul 2006 07:47:14 -0700

First off I would like to express my thanks for all those who gave me
suggestions on how to repair my space wars, I appreciate the help. First
off I do not like messing with the internals of some of my games because I
have a nasty habit of making things worse while trying to fix them, I know
its a special gift I have. My space wars had the problem that the picture
would start jumping mostly in the lower left corner which was the worst with
movements of up to 1 inch while the other corners were less so, While in
motion in the effected areas the sound was distorted somewhat. I believed
that the problem could be solved with a new cap kit and replacement lf13331.
I will not bore you with the hard times of trying to find a replacement but
needless to say I did. I replaced the caps in the monitor and was very
careful about orientating the polarities and making sure no unintentional
bridges were built, also while in there I touched up the solder at the
ribbon connectors and power connectors. The big day came and I reinstalled
the boards and monitor. I made sure when I took off the ribbons which way
the were orientated but alas for the power connectors which were not keyed
I failed to make note. For anyone who want to know the motherboard has the
wavy side of the connector turned to the right and the sound board has it
turned to the left. I relied on the way the connectors were hanging to help
me orientate the connectors originally. I sat back and threw the switch and
I got nothing at all. My first thought was now I have turned a machine
that was one of my favorites that had gotten annoying in to a 300 pound
coffin that was good for nothing but scrap. I then had the idea that maybe
I had connected the power up wrong so I turned the connectors insuring that
I had hooked it up improperly. Long story short is that I had blown 2 fuses
in the power supply and spent about an hour tracing the circuit board to
determine the proper orientation of the power connectors, take 2. I now
powered up the system and heard the explosion of a ship blowing up followed
by the fuses blowing again, great now I have really screwed this up and
trying to find a replacement monitor or someone who will fix it for me is
tantamount to impossible. I disconnect the yoke and power to the monitor
and it plays blind so I think well I didn't wreak the game boards. During
this time I have disconnected and reconnected cables and have moved the
monitor which is sitting in the cabinet but not bolted down. I decide to
reconnect the ribbon and power to the monitor, the breakers stay on,
wonderful. I get brave and reconnect the yoke and the game comes up and
runs on the monitor. The screen looks fairly stable only some minor
vibration but I can live with it because it is so very minor and I might be
feeling over cautious about seeing any movement now that I am sensitive to
it. Great time to play the game, on turning it on I always hear an
explosion sound. I set up credits and play the game runs well all sounds
work except for the explosion sound during game play, no boom, it only
booms on turning on the power the idiosyncrasy of the game is that when
power is turned on the game plays about 3 seconds of a normal game that you
could jump in and play so I think nothing of the explosion. I know all the
sounds can be generated because I can hear them but the game diagrams and
help I find on the Internet does not show what pins activate what sounds. I
get help from a reader here who tells me what chip encodes the pulses for
control of the sound board and all pulses are correct. I trace the control
pulses to the sound board to two chips and they seem to receive the inputs.
I discover that I have burned out the inverter buffer driver 7406 chip a
simple repair that while I am doing I install chip sockets on all my
soldered chips if I have to replace them. I power up the system I hear
nothing then the fuses blow again Pounding my head against the machine at
this time seemed like a good option and it felt so good when I stopped.
More moving and plugging and unplugging cables and like magic the problem
went away no more blown fuses. My only guess which I have never proved and
don't want to since the monitor is operational again was that the monitor
sitting on the metal plate for ground was not making good enough contacts
and I had a floating ground problem on the monitor that was causing fuses to
blow. I power on the machine no explosion sounds start the game Thrust
sounds work shot sounds work and explosion sounds work yea!!!! The only
problem is that now the screen is shaking again doing the electric boog a
loo with sound distortions when the space craft is in the effected areas.
Damn two months shot to **** trying to fix this thing and when all systems
start running the original problem is back. I change back the defective
chip the game starts with and explosion but now it still jitters and the
explosion sound does not work during game play, at this time it is truly
amazing that I still have this game sitting at my house. More research with
no clues I turn on the game and start fooling around with it during game
play I brush the credit switch and the monitor shakes less and the sound
distortions lessened. I tightened the connectors and things are better not
good but better. I pull the power connector off the sound board and the
screen becomes rock solid. I maybe on to something here. I put it back on
and wiggle it the screen jitters and sound distortion reoccur but the change
by when I move the power connector. I thoroughly clean both sides of the
power connection and reconnect it, problem is solved everything works great
I wish I had known that a dirty power connector to the sound board could
cause the monitor to wig out two months ago. Now I am very happy with it
and the only thing left to fix is to replace a burned out fluorescent bulb,
what can I break now replacing that?

• References:
  • space wars repaired saga
    • From: robert lipsett

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