I'm running into an odd problem. My Apple //e won't load any ProDOS disks. I've tested each disk on my //c, and //gs, and they work fine, but if it's ProDOS, my //e won't load it.
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Posted Fri May 18, 2018 12:43 PM
Occasionally it will simply say "Unable to load ProDOS," but most of the time the disks actually load for a few seconds before stopping, and displaying some odd text at the top of the screen. The errors are as follows:
ADTPro/ProDOS Master/Pasport Utilities (5.25 Disk II, Slot 5, or 6):
0DF8- A=10 X=C8 Y=C4 S=F5 (or S=EE)
AppleWorks 4.0 (3.5 UniDisk, Slot 6 only)
0C90- A=00 X=C8 Y=00 S=F3
These disks also display "APPLE II" along with the version of ProDOS, and a date in the middle of the screen, and Apple copyright info at the bottom.
Bank Street Writer Plus (5.25 Disk II, Slot 5, or 6): tree bwoop sounds (I really don't know how else to describe them), and then:
0C7F- A=00 X=C8 Y=C4 S=F5
There is nothing else on the screen.
Bank Street Writer III (5.25 Disk II, Slot 5, or 6) gets nothing but bwoop sounds, still no picture (not even Apple //e).
Some others (usually macros add ons for AppleWorks) it just spins the drive, and nothing else. Apple //e remains at the top of the screen. This is only with the 5.25 Disk II.
All these disks have been tested on my //c, and //gs. AppleWorks 4.0 has errors in load, but the //gs can work around them. The //c not so much, but usually I get the expected "Unable to load ProDOS" message. Also the bwoops from Bank Street Writer III are present on the //c, and //gs, but the program still loads. Bank Street Writer Plus loads without issue.
Also I have tried not having both controller cards installed at the same time, but the malfunctions persist.
Edited by DistantStar001, Fri May 18, 2018 12:46 PM.
Posted Fri May 18, 2018 9:12 PM
Which version of ProDOS and is the IIe enhanced (65c02)?
ProDOS 2.x (well, classic versions, not the new 2.4+) required a IIe enhanced, while 1.x will run on an original IIe, or a II with language card.
Edited by R.Cade, Fri May 18, 2018 9:13 PM.
Posted Sat May 19, 2018 12:12 PM
This is a //e enhanced. Anything after v2 seems to be giving me problems. I found an old apple //c tour disc with v1.1, and it booted fine. Interestingly, when I bootstrapped ADTPro with v2.0.2 over the cassette line it booted from a v2.0.2 system disk without a problem, and Bank Street Writer Plus gave me a splash screen. After that, it was acting up again. It took me forever to get it to run an internal diagnostic (even without the keyboard plugged in), but eventually I got it to run, and this is what I got:
I'm guessing that means one of my ram chips is bad. Also, given that there are 8 chips, and 8 digits, can I assume that my //e is trying to tell me which one? If so, then is it the second from the right, or second from the left, when the keyboard is facing towards me? (7 or 12 in fronton it?) And finally, if this assumption is correct, where do I go to get a replacement (other than another //e)?
Edited by DistantStar001, Sat May 19, 2018 12:22 PM.
Posted Mon May 21, 2018 7:51 PM
I replaced the RAM chip, and on the last diagnostic it gave me an MMU error. It loaded a ProDOS startup disk, but when I tried Bank Street Writer Plus, it loaded the splash screen, and then it just spun the disk, and nothing else. I tried the backup disk, and I got a similar error listed above. After that, *UNABLE TO LOAD PRODOS* on everything I tried.
The MMU seems to be a much harder component to find, but I think I might have located a generic substitute. the part # is 8250, and is described as a "8250B COMMUNICATIONS INTERFACE-40 PIN DIP PACKAG" (sorry about the uppercase, I bitterly just copy/pasted from the website). From the picture it seems to be the right size, and has the right number of pins, but I'd still like to know if it's the right part.
I'd post the picture, but I'm not sure if it's copyrighted, so this is the url: https://www.electron...cts/CHP8250.jpg
Posted Mon Jul 2, 2018 7:05 PM
So it's been a while since I've had a chance to work on this, but I've finally gotten a parts board that tested OK. Unfortunately, now that I've replaced the MMU, but there's still no improvement. I've replaced the IOU as well (I don't think there was anything wrong with the original, but since I know the new one is good, I figured that it wouldn't do any harm). No improvement. I know that my keyboard is less than optimal at the moment, as the T, and H keys aren't very responsive. Also I'm pretty sure that the open, and closed apple keys don't work either. I've tried replacing the switches, but it didn't seem to do any good. Over all, the machine seems to boot normal (with the exception of the noted proDOS issues), but I'm having trouble getting it to run its internal diagnostic. It seems to be hit, or miss when I unplug the keyboard (mostly miss), as the machine will often boot normally (displays "Apple //e"). My understanding is that when the keyboard is unplugged, is should default to it to the diagnostic, but it rarely does.
So, any suggestions?
Edited by DistantStar001, Mon Jul 2, 2018 7:06 PM.
Posted Tue Jul 3, 2018 8:25 PM
I've finally gotten this thing to run an internal diagnostic, and all it does is display random colors, beep 4 to 6 times, display the same patterns of colors, beep twice, and repeat. When it beeps, it seems to display rapid random characters, and patterns. I should note that it no longer gives me any error messages for the RAM, or MMU, however it's not telling me the system's OK either. This has been going on for a few minutes now, I ran a similar test on my //c, and it said system OK within a few seconds. There is nothing in any of the slots, and the keyboard is detached for this test.
I am dead certain that the keyboard is not working right. There is evidence of trace separation around some of the keys, and corrosion localized below the arrow keys. I tried to patch them, but it didn't seem to do any good. So I'm pretty sure it's time to replace it.
I'm pretty sure that the MMU, IOU, and RAM are all good now. I'm not so sure about the ROM though. The EF ROM appears to be a PROM, and I'm not sure where it came from.
Posted Tue Jul 3, 2018 8:58 PM
Since you have a parts board I assume you've already tried swapping (or removing) the 64k RAM card also, if you have one?
Other than that, if the RAM is good it sounds like a RAM addressing issue.
I guess it could be ROM, but that would be odd on a IIe. A II+, I see that all the time, but not on IIe.
You are positive it's a 65c02 and not 6502? You could swap that and see for sure... although unlikely, it could be bad.
There's not too much more in a IIe...
Edited by R.Cade, Tue Jul 3, 2018 9:00 PM.
Posted Mon Jul 9, 2018 10:03 PM
Ok, so I haven't swapped the processors yet (I need to get a new chip puller), but I did manage to get my keyboard fully functional. This means that I can run the internal diagnostic without partially dismantling my machine. Yay! However, when I run the diagnostic using the keyboard I get an error message (*RAM 01000000), when I unplug the keyboard I still get the same looping colors, beeps, and characters mentioned above. The error message is for the same RAM chip I replaced before, so I reinstalled the original, but swapped it with the first chip in the line, and got the same error in the second socket. I'm guessing that there's something wrong with the socket now, and that the chips were fine all along. What I can't figure out is why I get different results from the internal diagnostic when the keyboard is plugged in, vs when it's not?
Also, do I have to completely replace the socket, or would some contact cleaner do the trick? I'm asking because I'm not the best with a soldering iron, and I really don't want to destroy this board.
Edited by DistantStar001, Mon Jul 9, 2018 10:06 PM.
Posted Tue Jul 10, 2018 9:47 PM
So I sprayed some contact cleaner into the RAM socket. I checked with my local electronics store, and they said it wouldn't do any harm (they might have been wrong about that). At first it didn't seem to do any good (it didn't do any harm either), so I did it again. Still nothing, but after the third, it stopped booting all together. All it does is does is display various colored horizontal bars, about half the length of the screen, but the screen is filled with them on both sides. So I sort of gave up, I swapped the CPU, CD-ROM, EF-ROM, and Video ROM with the corresponding chips on my parts board, and plugged in the power supply, monitor, and keyboard, ran a diagnostic, and got: "system OK."
Note: I left my original MMU, and IOU in the parts board when I ran that test, so I'm guessing that there was nothing wrong with them.
With a working board, I then started putting the computer back together again, and ran another diagnostic: "*RAM 01000000", and "*RAM 01001100". I was able to narrow it down to the 80/64 column card. When that's removed, I get "system OK". I've also noticed similar issues loading ProDOS when the card's installed, except BankStreet Writer wouldn't load at all, and one disk just kept rebooting the computer every 5 to 6 seconds. Without the 80/64 card, all I get is a message saying that I need 128k, and apparently my 400(and some odd)k RAM Works card doesn't count.
The original board was tested, and gave errors "*RAM 01000000, and "MMU" even when there were no cards installed. I would still like to fix my original board (It was my grandfather's after all), but I'm guessing that might not be possible (Likely the result of him never turning it off, with the occasional exceptions of power outages, for the better part of two decades). Still, any suggestions would be appreciated.
In the mean time, I will enjoy my working //e, and start stalking ebay for another 80/64 card (I don't think that they're all that expensive). But if anyone has any suggestions on how to diagnose what the problem with this card, I would appreciate that as well (It was my grandfathers after all). It is a VidTech 80/64 card, and all the chips are socketed.
Edited by DistantStar001, Tue Jul 10, 2018 10:05 PM.
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