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Mike Chambers
August 13th, 2011, 08:11 PM
i got a couple new machines today, a Leading Edge D2 (286) and an ITT Xtra 8088 Professional. the ITT is fine, but the 286 will lock up as soon as i run Wolf 3D, Ultima6, and even Pacman. those are the only games i've tried thus far.

other apps seem to work fine, i've been online with chatting on IRC. my first thought was RAM, so i ran PC Check and tested the memory. base RAM checks out fine. any ideas, guys? doubt it matters, but the OS is MS-DOS 6.22.

EDIT: oh, and something odd... usually on these lockups, when i reset the machine it will just sit there making clicking sounds out of the speaker and not do anything until i shut it off for a moment. sometimes it will keep clicking even after i turn it off completely, and then back on, unless i leave it off for up to a minute.

i was thinking, what would be the most likely thing these programs have in common when i run them? they change the system timer speed. i wonder if this has anything to do with it? i've tried another VGA card btw. same issue.

EDIT 2: well, Ultima 6 now works on it fine with the third VGA card i put in there. the other 2 work fine in other machines though. wolf 3d still doen't work.

Mike Chambers
August 13th, 2011, 09:19 PM
wow, i was on to something with the timer thing. PC Pro says the system timer fails it's test. that's not good... anything that can be done about this without taking a soldering iron to the motherboard? i think i know the answer already. on the other hand maybe it's test is flawed. i just tried it on an 8088, it also failed on the timer.

pearce_jj
August 13th, 2011, 11:31 PM
I can't help you specifically but generally I'd approach it by cleaning it all out, testing the PSU for voltage and ripple then simplifying the system as much as possible and go from there. But I'm sure you're well on top of these things!

Do you have another CPU you could switch it to?

Mike Chambers
August 14th, 2011, 12:09 AM
the system is extremely clean inside. immaculate, actually. i haven't tested a PSU voltages yet, that's a good idea. i'll have to pull the PSU out to see exactly what sort of socket the 286 in there uses, i have another one i can throw in there as long as it takes the PLCC form. i wouldn't suspect the CPU itself personally, but it's possible. i think generally if a CPU goes bad it'll tend to quit working altogether. at least i've never run into one that only partially works.

pearce_jj
August 14th, 2011, 12:41 AM
Completely different era I realise but 'failing' CPUs are seen in servers with relative comonality - for example ESX(i) hosts start producing pink-screens periodically with messages like "Recursive panic on same CPU". Then the manufacturer provided system diags will generally identify the failing CPU, or if you're lucky and it's cache related then the onboard health stuff might pick it up (via ECC) and raise an alert before it starts causing problems. None of which applies to the 286 of course!

pearce_jj
August 16th, 2011, 03:16 AM
Just wondered if you'd got anywhere with this one?

Unknown_K
August 16th, 2011, 05:42 AM
Did the battery leak by chance?

Mike Chambers
August 18th, 2011, 11:30 AM
Just wondered if you'd got anywhere with this one?

nope, i've been hyperfocused on some assembly code i've been working on and haven't had a look at the leading edge in the past couple days, but i am going to try and see what happens when i go in it tonight.




Did the battery leak by chance?

good question! the battery seems to be under the PSU, but i'll have a look when i go in there.