Space Invaders

nomore25s

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Help, please. I'm trying to get my SID boardset working. I sent it out for repairs and while one issue seems fixed, the other is definitely not. Any suggestions on fixing this would be appreciated.

I have a modern switcher in it and voltages at the edge card are fine. Most times the game boots up "cleanly" other times it does not. Either way, eventually it looks the same - graphics get dimmer and scrambled. A lot of the text turns into upside down ? (question marks). The game continues to play (but impossible due to the graphics).

I'm including two images (good, vs. bad), hopefully you can see the detail.

I have a follow-up question I'll make in a separate post.

Thanks!
 

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2nd question

I'm trying to create a test-bench harness for Space Invaders. I thought I read that SI outputs composite video. I read that as the same as VCRs, etc. (the yellow connector). I took the two wires for video and alligator clipped them to a composite video cable plugged into my Commodore monitor's composite video input but I don't get a good picture.

I guess I'll go hook it up and then upload a picture in case someone has a suggestion.

Thanks
 

Right, I saw (and posted in) that thread. Thats why I thought I understood what needs to be done. But its not working. Maybe its something wrong on my monitor. I guess I'll find a TV that can take composite in and see if that helps. I'm getting a stable image on the monitor, its just not recognizable as anything.

I'll post some pictures later this evening - I most likely am just doing something stupid and hopefully someone will be able to point out my error.

Thanks
 
picture from commodore monitor - anyone recognize it?

Okay, I took a picture of what I'm seeing on the commodore monitor.

Can anyone clue me in to what that might be?

I did go ahead and verify that I am displaying a composite signal on the commodore monitor (dug out the VCR). So its not an incorrect setting/cable on the monitor side.

Thanks

EDIT: I'm using pin 17 and 18 from the 18 pin connector, btw.
 

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I think that pattern is displayed when there are bad ram chips. I have a PCB set that displays that same pattern in your photo. I haven't really had a chance to troubleshoot this board yet.

I was thinking about looking into this for testing the boardset:

http://www.outerworldarcade.com/arcade/space_invaders/space_invaders_test_rom.html

Drat, and I just ordered some ROMs....

Anyway, this pattern does not show up in the actual game. So something else is wrong. I guess I could have messed up the pinouts on the harness. I will double-check voltages tonight.

To reiterate, I have an original SI harness that was stripped out of a cabinet. I took the 18-pin edge connector and wired up the +5/+12/-5/ground to the switching PS and then pin 17,18 to the composite monitor. Does anyone see anything wrong with that (I'm not even hooking up the other two connectors (controls, sounds, etc).

Thanks
 
If you paid for a repair already, shouldnt it be guaranteed?

Just sayin'

Dunno - I sent them an email.

I need to make sure its a board issue and not a monitor issue. That is why I am trying to get my test-bench to display. If I can reproduce the weirded out graphics on my Commodore monitor then I'll be more confident that it is a board issue.

Originally I just assumed it was a board issue. With some of the score/numbers displaying as upside-down question marks, I can't see how a monitor problem would cause that - its just displaying an analog video signal.
 
If you're using a switcher for this, make sure it's set for +5.20vdc. I've had some issues with it set even slightly below get resolved by bumping it up a bit....
 
If you're using a switcher for this, make sure it's set for +5.20vdc. I've had some issues with it set even slightly below get resolved by bumping it up a bit....

Wow, that high? I had it up to 5.1 or 5.15, I think.

I'll give it a shot. At this point, I'm desperate.
 
I'm trying to create a test-bench harness for Space Invaders. I thought I read that SI outputs composite video. I read that as the same as VCRs, etc. (the yellow connector). I took the two wires for video and alligator clipped them to a composite video cable plugged into my Commodore monitor's composite video input but I don't get a good picture.

I guess I'll go hook it up and then upload a picture in case someone has a suggestion.

I've hooked SI up to a TV for shits and giggles... if you're going to an arcade monitor you should clip onto the vid and sync signals before they're combined.
 
I've hooked SI up to a TV for shits and giggles... if you're going to an arcade monitor you should clip onto the vid and sync signals before they're combined.

I followed the document for hooking up to a RGB monitor (connected off the two resistors). I received the same picture as the composite picture. So I again am stuck.

Maybe the +5 needs to be higher - I'll check it tonight.

It needs to be +5.2 at the motherboard, or at the PS?

Thanks
 
I followed the document for hooking up to a RGB monitor (connected off the two resistors). I received the same picture as the composite picture. So I again am stuck.

Maybe the +5 needs to be higher - I'll check it tonight.

It needs to be +5.2 at the motherboard, or at the PS?

Thanks

5V at the chips... if you're getting significant voltage drop between the PS and the board, replace the edge connector and clean the fingers.

Cranking up the PS to make a game 'work' is a hack.
 
I've read there are issues if the reset line is not connected to the power supply when you use a switching power supply. I'm not sure what happens when it's not hooked up but it allows a little time for +5 to become stable then it reset the processor and I've heard you need to account for this.
 
5V at the chips... if you're getting significant voltage drop between the PS and the board, replace the edge connector and clean the fingers.

Cranking up the PS to make a game 'work' is a hack.

Got it, thanks.

Is there a particular set of pins to check voltages at the pins?
 
I've read there are issues if the reset line is not connected to the power supply when you use a switching power supply. I'm not sure what happens when it's not hooked up but it allows a little time for +5 to become stable then it reset the processor and I've heard you need to account for this.

Hmmm, define "account for this" ? I thought I read where it just means it takes a while before the game comes up.

So, I'm fighting two issues here - my graphics glitches after the game comes up and I play it for a little while and hooking the boardset up to a bench-top monitor (ie, composite or RGB).

The 2nd issue is to rule out problems with the wg v1001 in the cabinet. Again, it would seem strange to me to see text changes to indicate a monitor issue, but....
 
I've read there are issues if the reset line is not connected to the power supply when you use a switching power supply. I'm not sure what happens when it's not hooked up but it allows a little time for +5 to become stable then it reset the processor and I've heard you need to account for this.

Most 8080s won't start up at all without a proper reset... they don't seem to set the PC to 0x0000 on powerup.
 
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