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Whats wrong with my Apple II Plus?

tevion5

tevion5

macrumors 68000
Original poster
Jul 12, 2011
1,967
1,603
Ireland
In the never ending saga to get my new Apple II Plus to do absolutely anything, I've discovered my earlier concerns with my langauge card are not my real issue.

I have learned so much about this machine in the last month. I now know that my Plus does not need a langauge card to use the Disk II drive and that the "language card" it came with was really just a ram card.

I ordered and received a new official apple langauge card (which I believe works fine in a II plus?) and I no longer get lines across the screen when I turn it on, therefore I suspect it works.

However, I am now convinced the Disk II Drive is my problem. When I try to load any disk with or without my new language card, I get a same problem. Most disks give me the same kind of error where it says something like "6853 F=C X=0 Y=0..." Etc. one disk gives me just the single word "ERR" at the top left and another fills the entire screen with the letters "@" and "A" in vertical columns!

Each disk sounds like its loading in the drive although very loudly. (Maybe that's normal, I have no experience with 5 1/4 inch drives. Way louder than a 3.5 anyway). Then after less than a minute, I get some kind of error.

I have tried taking out some and all of my expansion cards and have reseated the ram chips on my language card.

I must admit that when I first got it, I rushed to get it working with little knowledge as to why I was doing and inserted a disk while the system was running. I have read somewhere that this is bad practice. However, surely doing this once wouldn't have totally wrecked the drive? I mean if it does, then half of all Apple II owners must have broken theirs back in the day!

Is this indeed an issue with my DISK II Drive?
 

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tevion5 said:
I have learned so much about this machine in the last month. I now know that my Plus does not need a langauge card to use the Disk II drive and that the "language card" it came with was really just a ram card.
Click to expand...
Well, yes - that's what a "language" card is. A bank-switched set of memory for the last 16k, filling the Apple II (and II+) up to a full 64k that the 6502 can address. The name is historical - early versions of Pascal shipped with it, since it needed 64k; and of course it allows the dual-loading of Applesoft and Integer BASIC dialects.

tevion5 said:
However, I am now convinced the Disk II Drive is my problem. When I try to load any disk with or without my new language card, I get a same problem. Most disks give me the same kind of error where it says something like "6853 F=C X=0 Y=0..." Etc. one disk gives me just the single word "ERR" at the top left and another fills the entire screen with the letters "@" and "A" in vertical columns!
Click to expand...
Do you have any disks that work? Your disk drive may be out of spec with respect to rotational sped, which is adjustable with a potentiometer. The drive head may be dirty. But it seems likely that something between your drive and your floppies is out of whack. If every disk is bad... it starts to point at the drive as the guilty party.

tevion5 said:
Each disk sounds like its loading in the drive although very loudly. (Maybe that's normal, I have no experience with 5 1/4 inch drives. Way louder than a 3.5 anyway). Then after less than a minute, I get some kind of error.
Click to expand...
A minute is way too long. If a disk is simply booting DOS, it should take 10 seconds or so; more if it is an old DOS master disk that loads Integer BASIC. Here is a video that has decent audio of the initial startup of the drive. It goes on to load a copy-protected game which has a bunch of noises you won't generally hear, but you can get a feel for the initial head reset sound:
http://www.youtube.com/watch?v=Dub4nraPLlQ

tevion5 said:
I must admit that when I first got it, I rushed to get it working with little knowledge as to why I was doing and inserted a disk while the system was running. I have read somewhere that this is bad practice.
Click to expand...
Definitely not your issue.

It might be interesting to "boot" DOS via ADTPro - through audio or preferably serial, if you have a serial card. That would give you a means to get DOS loaded into memory, and then INIT a new disk to see if your drive can at least create a viable disk that it can itself read. See:
http://adtpro.sourceforge.net/bootstrapaudio.html#Bootstrapping_DOS
 
You might want to try reseating/cleaning the E0 and D0 ROMS. Of course, it could be a mirriad of things.

You could even try the disk interface in slot 5 instead of the preferred slot 6.

If you remove the disk interface card, I assume the machine drops into a "]" prompt when powered on?
 
OK, last guess, and clutching at straws here. It's difficult to get these going with no other hardware available. Reseating and cleaning all ICs is an option, but not one I'd be keen on. Sometimes just pushing the chips down into their sockets can assist, but this worked years ago before the IC pins and sockets tarnished to the point they would be at today some 35 years later.

Clean and reseat E0 and D0 ROMs (as previously suggested)

Clean/reseat/swap the 74LS138 ICs at locations H2 & H12

There are a couple of 74LS138s at F12 & F13 that you could swap with the others on row H to see if the problem changes dramatically.

The 74LS138 at F12 can be considered as the ROM selector.

These areas are usually associated with dropping into the monitor on bootstrap. IE, the ROMs and the 74LS138s at H2, F12 & H12.

However, the address given might be associated with a RAM chip in Row D. So as previously suggested by tdiaz, swapping this row into Row C might be advantageous.

Of course, checking the voltage output of the power supply (when loaded) would be another "lazy fix".
 
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