Apple II c repair keyboard and check disk driver error

[Giordix]

Hi all,

I'm new in this forum and I want to say hello to all and sorry my bad english!

I'm trying to repair an Apple II c computer that was stocked in my house for many years. When I stocked it, like 15 years ago, it works without no problem but few days ago I have reconnected it and I have discovered two big problem:

- First was a strange behaviour of the keyboard: all the special characters like "( ) , ; -_ " and numbers works great but all the other letters don't come on screen (same for the number "5" only): when I press the keyboard button the cursors on screen flicks, so I think something happens... but without letters I can't put any command

- Second problem was that every disc I use, give the message "Check Disk Drive": I have tried many disk, most are Official Apple Disc coming with the PC, other are old games and similar but I have the same result

I have disasseble the PC, make a faster clean from dust, check the keyboard buttons and cable and all appear ok but first problem remains

For the second problem, I tried to clean the disk reader parts, and also, I have tried to use another disk reader getting it from the extenral drive (I have also the external driver but I can't use it directly because can't put commands to active it) but the result is the same.

 

Here you can found other image and videos:
https://drive.google.com/drive/folders/14nbEQOa3n7xhUkG23BAJj1O_ADQ0ZhKy?usp=sharing

How can I do for trying to repair it? I need a new keyboard? Where I can buy it? You think both disk reader are broken or ALL my 5 inches disk are unreadable? Where I can buy a disk that I'm sure it's work to understand if is the disk reader or the 5 inches floppy? Other ideas?

Glad of your help

[DistantStar001]

Try booting the computer without the keyboard to start.  Like the //e, most //c's will boot straight to the internal diagnostics when the keyboard is detached.  There are a few ROM versions that don't, but it's worth a try.  If that doesn't work, you can try reattaching the keyboard and holding down the solid-apple key while powering up (of course that only works if the specified key is working).  

 

If you successfully get into diagnostic mode, the computer will flash a series of colored blocks on the screen and beep rapidly, after which it will either display "System OK", repeat the process (both are good), or give a message informing you of a defective component.  Regardless, this should give you a baseline of how functional the motherboard is.

 

For the motherboard.  I've noticed that the paper on the speaker has completely deteriorated, and there's a mild case of rust on the casing for the voltage regulator.  This tells me that there's a possibility that moisture may have gotten to the motherboard as well causing corrosion in the sockets, or on the underside.  

 

I would suggest removing the board completely to make sure that there's nothing shorting it.  Maybe give it a quick go over with a toothbrush and some 99% rubbing alcohol.  Then inspect the board for any damaged solder joints.  Reflow or add solder as needed.  Same for the keyboard itself.  I've resurrected several stubborn mechanical keyboards this way.

 

If the computer has an RF shield underneath, then there will be some sort of insulating barrier between the board and shield.  Sometimes this is made of cardboard, which can retain moisture or deteriorate.  If this is the case, you can fashion a new barrier, or just discard the RF shield altogether.  

 

Also, try reseating the socketed IC's.  I would spray a little contact cleaner (DeOx-it is best) in them.  I would concentrate my attention on the keyboard encoder, and spray some contact cleaner into the keyboard connector as well.  

 

As for the drive, I fear you may have a bad read-head.  You can try cleaning it again with some rubbing alcohol on a q-tip, however, if the drive were detecting a disk at all, you should be getting a message saying something along the lines of "Not a boot disk" or "Disk error".  At the very least, the head should move indicating that it's finding or trying to read data.  Instead it's just spinning for a minute and then stopping, which is typical behavior when the drive is empty.  

 

Depending on the external drive you have, it may be possible to connect it directly to the internal drive connector on the motherboard (but you will need a longer ribbon cable to do this).  If you have the external drive that matches the //c (scroll down on this link and you'll see it: https://apple2history.org/history/ah09/), then the mechanisms are interchangeable.  You can just take that drive apart and install it directly in your //c (at least until you get a replacement drive).  Honestly, if the read-head is bad, then it might be easier to replace the entire drive than source a new head.

 

In any case, I hope this helps.  At the very least, it should help narrow down your problems.  Best of luck!

 

[Giordix]

12 hours ago, DistantStar001 said:

Try booting the computer without the keyboard to start.  Like the //e, most //c's will boot straight to the internal diagnostics when the keyboard is detached.  There are a few ROM versions that don't, but it's worth a try.  If that doesn't work, you can try reattaching the keyboard and holding down the solid-apple key while powering up (of course that only works if the specified key is working).  

 

If you successfully get into diagnostic mode, the computer will flash a series of colored blocks on the screen and beep rapidly, after which it will either display "System OK", repeat the process (both are good), or give a message informing you of a defective component.  Regardless, this should give you a baseline of how functional the motherboard is.

 

For the motherboard.  I've noticed that the paper on the speaker has completely deteriorated, and there's a mild case of rust on the casing for the voltage regulator.  This tells me that there's a possibility that moisture may have gotten to the motherboard as well causing corrosion in the sockets, or on the underside.  

 

I would suggest removing the board completely to make sure that there's nothing shorting it.  Maybe give it a quick go over with a toothbrush and some 99% rubbing alcohol.  Then inspect the board for any damaged solder joints.  Reflow or add solder as needed.  Same for the keyboard itself.  I've resurrected several stubborn mechanical keyboards this way.

 

If the computer has an RF shield underneath, then there will be some sort of insulating barrier between the board and shield.  Sometimes this is made of cardboard, which can retain moisture or deteriorate.  If this is the case, you can fashion a new barrier, or just discard the RF shield altogether.  

 

Also, try reseating the socketed IC's.  I would spray a little contact cleaner (DeOx-it is best) in them.  I would concentrate my attention on the keyboard encoder, and spray some contact cleaner into the keyboard connector as well.  

 

As for the drive, I fear you may have a bad read-head.  You can try cleaning it again with some rubbing alcohol on a q-tip, however, if the drive were detecting a disk at all, you should be getting a message saying something along the lines of "Not a boot disk" or "Disk error".  At the very least, the head should move indicating that it's finding or trying to read data.  Instead it's just spinning for a minute and then stopping, which is typical behavior when the drive is empty.  

 

Depending on the external drive you have, it may be possible to connect it directly to the internal drive connector on the motherboard (but you will need a longer ribbon cable to do this).  If you have the external drive that matches the //c (scroll down on this link and you'll see it: https://apple2history.org/history/ah09/), then the mechanisms are interchangeable.  You can just take that drive apart and install it directly in your //c (at least until you get a replacement drive).  Honestly, if the read-head is bad, then it might be easier to replace the entire drive than source a new head.

 

In any case, I hope this helps.  At the very least, it should help narrow down your problems.  Best of luck!

 

Thanks for you message.

Very clear and I know I must recheck the mainboard and try to clean it better. For the contacts and for the sockets, can you suggest some specific spray on amazon? Unfortunaly I don't have the tools for resolding. ABout the drive I have tried to clean the head with alcool without any success. As you can se in the video, the head doesn't move after the first read (happend only on time in many many trial): maybe all of my disk are broken?

 

Yes I have the correct external drive: that drive is identical to the internal drive but when connected the result is the same. This is why I was wondering about a problem on all my disk or the  mainboard....

[DistantStar001]

12 hours ago, Giordix said:

Thanks for you message.

Very clear and I know I must recheck the mainboard and try to clean it better. For the contacts and for the sockets, can you suggest some specific spray on amazon? Unfortunaly I don't have the tools for resolding. ABout the drive I have tried to clean the head with alcool without any success. As you can se in the video, the head doesn't move after the first read (happend only on time in many many trial): maybe all of my disk are broken?

 

Yes I have the correct external drive: that drive is identical to the internal drive but when connected the result is the same. This is why I was wondering about a problem on all my disk or the  mainboard....

 

 

For the contact cleaner, my recommendation is Deoxit.  Amazon link: https://www.amazon.com/Hosa-D5S-6-DeoxIT-Contact-Cleaner/dp/B00006LVEU/ref=sr_1_2?crid=TO2488YRVAZC&keywords=deoxit&qid=1641927279&sprefix=does%2Caps%2C155&sr=8-2

 

For the drive, it really depends on how you connected the second drive.  A stock //c will not boot from an external 5 1/4in drive, only a 3 1/2in.  This is due to the way the drives are addressed, slot 6, then drive number (same as a ][, ][+, or //e).  For the 5 1/4in this means that slot 6, drive 1 is always going to be the internal connector.  The external port is addressed as slot 6, drive 2, and thus will not boot.  You need to disassemble the external drive and connect the mechanism to the internal ribbon cable to test successfully.  

 

If you have already done this, then there are three possible issues that I can think of:

 

1) The read heads on both drives are bad.  This is possible if both drives were stored in the same conditions, but unusual for two drives to suffer the same malfunction.  Still, if they do have the same problem, then my bet is on these components.  

 

2) An issue with the analog boards in the drives.  Also possible, but like I said, unlikely that both drives would have the same malfunction.  However, sometimes failures in different components can cause the same issue.  You could swap the boards between the drives to see if there is any change in behavior.

 

3) An issue with the IWM (Integrated Woz Machine) chip located at D-2 just behind the composite port on the motherboard.  It's basically a disk controller card on a chip, and is responsible for all floppy controls.  However, the computer does seem to be controlling the drive, as the read head is being sent to track 0 on boot.  This would indicate that the chip is working, and they're pretty reliable as well.  In any case, the chip appears to be soldered in on your board, so removing it will be a problem (to say nothing of sourcing a replacement).

 

I hate to say it, but if the issue really is related to either 2 or 3, and swapping the analog boards doesn't resolve the problem, then you are going to need soldering skills and equipment to fix them.  Or seek replacements.

 

As for the disks.  I can't tell you if they're good or bad.  Absent any visible signs of wear, mold, or other damage, you would need a working drive to be sure.  What I can tell you is that if the internal drive was functioning, the read head would move and you would hear the drive seeking data from the tracks.  This isn't happening.  The head is just sitting there like there's nothing to read.  That tells me that the immediate problem is more likely the drive itself than any particular disk.  

 

If you need to, my best suggestion is eBay to source a new drive or other component.  Alternatively, you could put a want post in the market place section of this or another Apple or vintage computer related forum.  

 

Also, it might benefit you to seek out another //c as well.  I'm not saying you should give up on this one.  Far from it.  This machine has life, and I do think it can be repaired!  But having another (especially if it's working) will allow you to swap parts between them, making it much easier to detect bad components.  

 

In any case, good luck!  And if I can think of any other suggestions I'll post them here.