Tech: Galaxian PCB w/ Garbage Screen

Archived from groups: rec.games.video.arcade.collecting (More info?)

O.k. I have a Galaxian that is currently displaying a fixed screen of
garbage on power up. This board has been modified to accept a
switcher, in that the diodes at D4-D6 have had one leg lifted from the
board, and jumper wires soldered from the +5v, & +12v edge pins to
coresponding traces. I also noticed that the 78GUIC voltage reg. has
been completely removed, rather poorly as well.

I have searched the NG and found some logs that point out the 2114 RAM
and/or the LS245 as possibilities (athough the 245's are not on this
board). I have made sure that I have good, solid voltages going into
this board. Physically, it is o.k. with no broken traces or
bent/broken pins. I am wondering if the modification may have
something to do with this, or if it is a failure in one of the chips.
Appreciate any assistance on this, and have a great holiday. Thanks
for the time.
3 answers Last reply
More about tech galaxian garbage screen
  1. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Yes, I am located in Ohio. The 2114 RAMs are not socketed...I have
    read that the solder pads on these boards aren't the greatest either
    for swapping componens...I don't think the mod has done any damage, but
    I do not have the means to test any of the chips to see if they are
    indeed at fault.
  2. Archived from groups: rec.games.video.arcade.collecting (More info?)

    On 3 Sep 2005 09:18:24 -0700, "Rich Potts" <rtp16@hotmail.com> wrote:

    Could be the RAMs, ROMs or the circuitry that connects to those chips
    plus the CPU and/or its' I/O.

    I'd first check that the ROMs are okay and also, if socketed, test the
    2114 RAMs near the main program ROMs (if you have any way to test
    these RAMs such as another board).

    I doubt if the DC mod has affected anything (unless it's been done
    badly/incorrectly).

    I assume you're in the US?
  3. Archived from groups: rec.games.video.arcade.collecting (More info?)

    On 3 Sep 2005 14:34:07 -0700, "Rich Potts" <rtp16@hotmail.com> wrote:

    >Yes, I am located in Ohio. The 2114 RAMs are not socketed...I have
    >read that the solder pads on these boards aren't the greatest either
    >for swapping componens...I don't think the mod has done any damage, but
    >I do not have the means to test any of the chips to see if they are
    >indeed at fault.
    >

    I see. Well, might be an idea to see if you can get it fixed by one of
    the experts around here (I'm in the UK so can't help I'm afraid -
    unless you want to pay a fortune in shipping :-)
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