Space Invaders Deluxe - Dead

AAirhart

Well-known member

Donor 2011-2012
Joined
Jul 1, 2011
Messages
1,932
Reaction score
17
Location
Crafton, Pennsylvania
I picked up a SI Deluxe a few weeks ago....and I am greeted with a screen full of garbage.

Here's what I've done so far.....
Tested the +5, - 5 and +12 at the power supply.

First two were fine, 12v read at 10v.
The 18+ read at 15.
Replaced the 12v regulator. Now I have +12 and a little over 17v where I should have 18.

The reset circuit test point reads a nice and high 2.5v instead of .5.
When I force a reset I hear a slight tone/garbage and I get the horizontal lines filled with a ton of dots (assuming a few RAM chips are bad too, I got a Braze kit to diagnose that...but can't get it it to boot.)

Where should I begin? Not sure what needs changed out in the reset circuit and I'm thinking the 8080 may be bad..but cannot confirm.
 
Pic 213 is before forcing a reset. Pic 217 is after. Thinking the processor is dead and I have some bad ram.
 

Attachments

  • IMAG0213.jpg
    IMAG0213.jpg
    23 KB · Views: 37
  • IMAG0217.jpg
    IMAG0217.jpg
    22.6 KB · Views: 36
  • SIpower.jpg
    SIpower.jpg
    47.4 KB · Views: 33
  • DSCN13812.jpg
    DSCN13812.jpg
    88.5 KB · Views: 27
Last edited:
Check all of the connections and dip switches. I just had a board with a frozen garbage screen and it seem to be a dip switch. Sometimes, not always, it is just something simple.
 
I'm not an expert but that looks like bad ram to me. There's a SI test ROM you can burn that will test your RAM.
 
Pic 213 is before forcing a reset. Pic 217 is after. Thinking the processor is dead and I have some bad ram.

I kinda remember seeing something like that on my SI when I was working on it. I had the board hooked up to a switcher, but I wasn't doing anything with the reset line (which you've already mentioned). I'm willing to bet you have a decent boardset and you're just having problems with the reset line. Trace it back and see if you can find where it's faulty... you need that reset line to go low and do it's job. You can't really start working on much of anything else until you've got that squared away.

You can try putting in a switcher if you want, but I do like running stuff off the original power supplies if at all possible. An easy way to put one in there is what I did on my friends SI, we just removed the bridge rectifier to isolate the power supply from the line. Then tacked wires from a switcher to points on the bottom of the Midway power supply. Just tacked on the +5, -5, 12, GND and then tied the reset line to GND to hold it. It was supposed to be temporary... but worked well enough and just left it like that. If the board works like that, then you can put the bridge back in and start working on the original power supply to see what's going on with that reset line.
 
Currently can't be the slam switch, there isn't one or a coin door. Someone decided to remove it and add a credit button.

To "bypass" the reset circuit, does it need a constant ground to stay active?
 
Currently can't be the slam switch, there isn't one or a coin door.

Mine doesn't have one either, just 2 bare wires that sometimes touch the coin door or each other and close the circuit, putting the machine into a constant reset loop. Not saying that's your only issue or even part of your issue, but it has stumped me and another guy at least twice, and one of the rug screens I've seen looks like one you posted. Find out where the slam switch/reset wires terminate, if that checks out, then rebuild the power supply. After that, start with the ram, the other chips and sockets on the boards as they are known to rust and rot.
 
Currently can't be the slam switch, there isn't one or a coin door. Someone decided to remove it and add a credit button.

To "bypass" the reset circuit, does it need a constant ground to stay active?

I tied my friend's to ground and it works just fine.
 
It's alive!!! Kind of...
Added a jumper to the PS board and grounded the reset line.
I have the Braze multigame installed so it booted to 1 tone (occasionally 6 tones) and the words CHECKSUM FAIL. So 8080 is alive and kicking, appears a RAM transplant is in it's future....and a rebuild of the power supply.
 
Last edited:
Back
Top Bottom