I worked on four Missle commands for the first time and got three of them working (what a design - not designed for easy hardware debugging). The fourth board has me stymied. It comes up with one high beep for one of the 4116s being bad which I have replaced twice but the error still comes up. If I intentionally remove any other drams the correct beep error is caught. I've checked continuity to the suspect Dram but all is fine. I've gone over all of the sections of the board and they all seem to be working but the board as a system won't come up. It just keeps looping the dram beeping test. Any suggestions based upon your collective experience would be welcome. Thank You and Best Regards, Bill _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist
Any suggestions based upon your collective experience would be welcome.
In that situation I usually fall back on a fast (100MHz+) digital (so you can catch glitches) oscilloscope and/or logic analyzer. I agree - it's not a straightforward design... Alex ---- ayeckley@elektronforge.com www.elektronforge.com _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist
I've usually found that the buffer ICs have issues when you get a bad beep. So I'd change the 74LS245/373's on the RAM/ROM address or Data buffers - starting with the data buffers. Or grab a Fluke 9010A and the correct pod and troubleshoot professionally... John :-#)# At 7:14 PM -0500 6/9/05, Bill Karkula wrote:
I worked on four Missle commands for the first time and got three of them working (what a design - not designed for easy hardware debugging). The fourth board has me stymied. It comes up with one high beep for one of the 4116s being bad which I have replaced twice but the error still comes up. If I intentionally remove any other drams the correct beep error is caught. I've checked continuity to the suspect Dram but all is fine. I've gone over all of the sections of the board and they all seem to be working but the board as a system won't come up. It just keeps looping the dram beeping test. Any suggestions based upon your collective experience would be welcome.
Thank You and Best Regards,
Bill
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I'm setting up to repair color and B&W vector games. For the monitor, I'm looking for something small and compact yet will get the job done. I'm tackling Asteroids first and am building a jamma adapter for it. I know you can hook up to a scope for the B&W. Any links for vector repair resources, repair logs, etc. are welcome. Thank You and Best Regards, Bill _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist
Hi Bill, Try this link for some good asteroids tech notes... http://www.ionpool.net/arcade/asteroidtech/asteroidsrepair.html ____________________________________________________ Yahoo! Sports Rekindle the Rivalries. Sign up for Fantasy Football http://football.fantasysports.yahoo.com _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist
Mark came up with a neat color adpater for scopes. http://www.leopardcats.com/supergun/atarixy_adapt.htm That's your best bet unless you have a 13" Amplifone color monitor. As far as B&W, I use a 13" out of an Asteroids cocktail (had bad burn-in) and I'm not afraid of damaging it. tm Jean-Christine writes:
Hi Bill, Try this link for some good asteroids tech notes...
http://www.ionpool.net/arcade/asteroidtech/asteroidsrepair.html
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participants (5)
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Alex Yeckley -
Bill Karkula -
Jean-Christine -
John Robertson -
tom mcclintock