I remember seeing some Space Invaders pics

Rrcade

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I've got a ram/rom whatever problem, I know it's on the Motherboard, and I remember seeing some pictures of monitors with various garbage on the screen that helped narrow down the culprit, anyone know of these photos?

oops wrong forum...don't hate me
 
Hate hate hate hate man I'm feeling angry today.

Anyhow make a new thread in repair, and do you have an eprom burner and any 2716's laying around?
 
I've got a ram/rom whatever problem, I know it's on the Motherboard, and I remember seeing some pictures of monitors with various garbage on the screen that helped narrow down the culprit, anyone know of these photos?

oops wrong forum...don't hate me

I don't think you're nuts; I vaguely remember seeing those pictures somewhere as well.
 
(Note this is in my own experience, YMMV)
If you're getting garbage on the screen, make sure to check all of the likely culprits first (edge connector securely connected, +5, -5, +12, +18 v are all good) Tips on how to do so here
If all of that checks out then remove the ROM at location H
you should get a screen that looks like in this video- basically a thick white line, a thin black line, a thin white line, and a thick black line, repeated thru the whole screen)


If there are any breaks in the pattern of lines, that is usually symptomatic of bad RAM. if the lines are straight and there are no breaks in them, its usually either a Rom issue, or (more likely) a bad ROM socket.
One fix is to send the board to Elektronforge for repair.
Or you could buy the Braze SI Multigame (which bypasses the ROM's)
You could try to locate the Space Invaders test ROM for troubleshooting, however, if the rom socket is bad, that won't help much... (The Braze kit also has a troubleshooting function in it)

There are others who have way more experience in this than I do, so hopefully someone else will chime in with additional suggestions, but at least this will get you started.

Edit: Found the pics of the garbage I was getting prior to removing ROM H:
si4.jpg


and After:
100_0300.JPG
 
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that can also happen if you're having a reset circuit issue, too. if it's that kind of issue, check your voltages, and the edge connectors. also, it doesn't hurt to hit all the pins on the power supply's socket with your soldering iron. i had cold solder joints all over my power supply board causing a reset issue like that.
 
Your before pic looks like mine, how did you fix it?

I just bought the Multigame (ArcadeShop is the cheapest place for it, I think it was about $70 or so shipped), as based on my testing, I figured the ROM sockets were bad, oh, and I also bought a rebuilt power supply, as the voltages were off on mine. In hindsight, I should have just rebuilt it, but at the time TNT Amusements was selling em on eBay pretty cheap...

That being said, it could be a lot of things, I wouldn't assume that the SI Multigame would necessarily fix it. From what I've seen the three biggest issues are that the power supply isn't supplying the right voltage, the ROM chips or sockets are bad, or one or more RAM chips is bad.

I would say the first thing to do is check the power supply to make sure you're getting the proper voltage from it. If you aren't getting a good +5, -5 or +12 that could be the problem (I think the +18v just runs the soundboard, so if that's bad the boards may work, but you would have no sound or at least issues with the sound) If any of the voltages are off, I would either track down a working PS, or rebuild yours.

If the voltage checks out, carefully remove the rom from location H on the board, and turn it back on and see if you are getting a pic like the second one. Those ROM sockets are pretty flaky, so that's a pretty common problem. If you're getting a pic like the second one, then the RAM is probably good, and you're looking at a ROM issue.

By the way, there's lots of good information on BrentRadio's website, as well as Elektronforge.com

Oh yeah, here's a good site too: http://www.marvin3m.com/video/seawolf.htm
It's for SeaWolf, but they are very similar boards with very similar issues


(Note, to the best of my knowledge this information is accurate, if there are any experts out there that have a better working knowledge of SI, feel free to make any corrections :D)
 
that can also happen if you're having a reset circuit issue, too. if it's that kind of issue, check your voltages, and the edge connectors. also, it doesn't hurt to hit all the pins on the power supply's socket with your soldering iron. i had cold solder joints all over my power supply board causing a reset issue like that.
Thanks, yeah I forgot about that reset circuit. There is a test for that as well on the elektronforge site. Check that, along with the +/-5v and 12v
 
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