Jump to content

Space Invaders Deluxe - Bringing Back A Parts Unit


SNESNESCUBE64

57 views

 Share

On the bench today was a Space Invaders Deluxe that I had grabbed off the pile. This one had unfortunately been a parts unit, as someone had taken several parts off the board, probably to fix another Space Invaders board. It was also pretty dirty, so I had to give it a bath.

20211024_173333.jpg.94dd30de7296c88a3b903a68a9b2c0fa.jpg

After washing the board, my first thing was to attend to the missing parts. It was missing a 9316 (Really a 74161 counter), a 74ls04, and an Intel 3245. The intel 3245 has become a bit more difficult to get a hold of as it was discontinued quite some time ago. So this was actually an opportunity to try to use a Soviet equivalent, which could be obtained for much cheaper because there is more NOS of that left behind. For this I used the K170AP4. 

20211024_201505.thumb.jpg.6ebed9e283ec3ba6c8799bc7a3309dd7.jpg

Another part that I noticed was missing was the 180pF tuning capacitor that was used to help the crystal oscillate. Unfortunately, I did not have that particular value available. I did however, have a bunch of 56pF capacitors. You can add capacitance by putting capacitors in parallel, so I solder three of them to leads and soldered them onto the board to get 168pF, which is probably close enough.

20211024_190340.jpg.3ff1f260dd4a066cf59990edd8900344.jpg

After replacing all the missing parts, I found that the game had a dead short on the 12V rail, which is obviously no good. One way to kind of narrow down a short like this is to utilize your multimeter if it is sensitive enough. The closer you get to the short, the lower the resistance will be. First place I checked was the tantalum capacitors, as those have a tendency to short out. It ended up being one of the tantalums by the RAM (shown below). I removed it and replaced it with an electrolytic that I had since I don't stock tantalums.

20211024_200026.thumb.jpg.ec9a164bfb51215809bd42634c7aa7c8.jpg

After the power situation was taken care of, I hooked it up to find that it booted to garbage. First thing I did was reseat the ROMs and the CPU as midway loved to use bad single wipe sockets.

20211024_195806.jpg.cc7c3d67811dbbccf718cfd5d744b49f.jpg

After reseating the chips, the game fired right up and worked as it was supposed to, another board back from the dead! It's always a shame to see people use these things for parts. Sometimes it's difficult, especially with custom chips and whatnot.

20211024_201229.thumb.jpg.5d972cc2832f64366237f376dca7b06a.jpg

  • Love 1
 Share

0 Comments


Recommended Comments

There are no comments to display.

Guest
Add a comment...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...