Re: TECH:Two Lunar Lander issues no y or z out & a "resetting" issue.

I don't have the details in front of me, but you basically want to make the cpu so it stops waiting for the vector generator. The idea is that you want to see if the game will play blind regardless of the DVG. There are some asteroids repair guides available that talk about this in more detail. I'd check the vector section on gamearchive for more information.

Jon

At 02:15 PM 8/22/2002 -0600, you wrote:

>Hello,
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>I thought it was time for me to actually join this list since I have 3 vector games that always seem to need one thing or another. I spent a several hours over the weekend going through the list archives and I was very impressed with the knowledge base of the people here and the intelligent thought provoking discussions with minimal flaming. I have grown slightly weary of RGVAC and all the FS/FT, flame wars and general BS etc. I look forward to participating where appropriate with this group.
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>I ve been collecting for about 6 years so I ve been around the block with some minor board and monitor issues (edge connectors reseating sockets, replacing sockets, burning eproms, cap kits etc.), but as yet I haven t done anything along the lines of logic troubleshooting. That brings me to this point& requesting some help.
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>I rescued this Lunar Lander from a partially burned out barn. It s actually in great shape especially considering what it s been through. If it were junk I wouldn t even be bothering with it, but there are relatively few LL s left&
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>What I ve done so far: the symptoms have remained consistent throughout all these changes so I haven t mucked anything up. I replaced the edge connector and pins. There were 2 eproms missing so I replaced those (the self test eprom was one of them). Most of the eprom IC sockets had some corrosion on them so I replace all the sockets. I also replaced big blue because of a buzzing issue. I capped the AR board. I also installed ic sockets for the 2- 2111 s (the 9111 s had been socketed previously with 2111-1s. I simply replaced the corroded socket) and I socketed the 4- 2114 s. A potential issue may be that the 2111a-4 s @ e/f-2 were replaced with 2111-1 running at 500ns instead of the <450ns typical. Finding the proper 2111a4 has been elusive. All board voltages are where they should be.
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>I have 2 issues and I m not sure which one to tackle first.
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>Issue1:
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>Basically the story is that my LL passes the self test, but will not play in game mode. In self test all beeps indicate all is well and I can hear the 3 thrust sounds and the crash sound just like it s supposed to. However when I flip the switch to game mode nothing really happens. It would appear that the game is resetting. The X out will show up on a scope for about ½ a second then flat line for ½ a second, then show up again& this consistently repeats until I shut it down. In self test X out on the scope shows up just fine no resets. I have tried grounding the WD and the coin counter clicks 3 times then nothing then it clicks 3 times again. I haven t been able to find an explanation for this yet. I did my best to use my logic probe to check a few things out to see if there is a problem with the watchdog circuit, and I found that pin 40 on the 6502a is being held HI so the CPU doesn t appear to be resetting. Can anyone think of some other things to check?
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>Issue 2:
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>There is no Y or Z out voltage X shows up just fine. Sometimes for the first 5 seconds or so there will be some activity on the X axis but it eventually flat lines Can anyone think of what may cause this? I have checked the entire board for broken traces and the both of the y trim pots checked out fine. I have unhooked the monitor until this output issue can be resolved for obvious reasons.
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>Any idea which of these two issues I should tackle first, or does it not really matter?
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>LMK if there is any more information required, it would be nice to resurrect this game& More importantly I would like to fix this game myself (with help from the group) for the satisfaction of reviving it.
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>Any ideas or assistance is ***greatly*** appreciated.
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>Thanks for your time.
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Received on Thu Aug 22 14:25:36 2002