apple IIc will not write to disk

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apple IIc will not write to disk

hello

 

im new but iv lurked around on and off.

 

so i have had a apple iic for awhile and just recently got a serial cable to use ADTpro. the problem is that i get "I/O ERROR" i thought it was my disk drive being flaky so i got a new old one off ebay and it does not work either.

 

i have been going through the SAMS but there is a page missing with a basic program to test the drive. i would just buy the sams but i dont want to pay $20 if its just going to be the same as the free pdf with the missing page.

 

long story short does someone have page #4 from the troubleshooting section in the chaper on the disk drive.

 

thank you
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Assuming you have a disk that

Assuming you have a disk that can boot to basic, you can run a quick program to try and write a text file to a disk and see what the error code is returned.

 

10 ONERR GOTO 100

20 D$=CHR$(4)

30 PRINT D$;"OPEN TEST"

40 PRINT D$;"WRITE TEST"

50 PRINT "TESTING"

60 PRINT D$;"CLOSE TEST"

100 PRINT PEEK(222)

 

 

If it returns 4, then its an issue with the drive's write protect circuit. I tested this on my own //c, so pending any typos when I typed this post on my PC, I know it works.

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i dont have a disk that can

i dont have a disk that can boot to basic. i had the disk "getting down to basic" but it would never boot because it would claim that it was "write protected".

 

thats what started this discovery, i assumed the disk was bad because it was from the 80's and it would read other disks.

 

i have an old 10mhz scope that i have been using to probe around and i dont believe it is the protection circuit because pin3 on IC 4B is high and low when it should be however i can not test further beacuse i do not have the test program from page 4 to run so i can probe the drive for pulses.

 

right now i have rom version 4, blank disks, orogan trail, and a serial cable.

 

thank you

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undone.evil wrote:i dont have
undone.evil wrote:

i dont have a disk that can boot to basic. i had the disk "getting down to basic" but it would never boot because it would claim that it was "write protected".

 

thats what started this discovery, i assumed the disk was bad because it was from the 80's and it would read other disks.

 

i have an old 10mhz scope that i have been using to probe around and i dont b

 

If both disk drivess don't work then there's something else that's causing the issue. 

Better start with the basics.  Like making sure the drive's read / write head is clean.  Use a cotton swab and isopropyl alcohol or "Ronsonol" (Zippo-lighter fluid) which works terrific.  

 

And check that it goes to track zero properly on boot up - it should sound like a chugging sound for a second or three, but take the cover off and observe it.

Does the drive format the diskette in ADTPro?  (Use the speediboot option on your modern PC to transfer ProDOS to the IIc, followed by ADTPro - it should do it right after transferring ProDOS)

Do you have an external drive for your IIc or did you just replace the internal drive?  Either way you'll want to take the covers off and access the head for cleaning.

 

Examine your diskettes physically.  If you get I/O errors, then the head can't read or write properly - hence cleaning, but it could also be your diskettes.

Look in the track zero area.  Is there a tiny circular scratch near the outer circumference?  Old diskettes can be prone to mould growth and it accumulates on the head (again, cleaning) and then as the drive goes to track zero it proceeds to scrape away the actual magnetic media due to the buildup on the head and rendering the diskette itself useless.

 

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the drives are clean and have

the drives are clean and have no problems other than they will not format/write to a disk. i dont think its the disks because i tried to format side 2 of my oregon trail disk and i know its good. it did delete some information before it failed because it used to say "flip disk to side 1" but now it doest say anything.

 

i put a short video of what it is doing on youtube - video

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Well, if it was a write

Well, if it was a write-protect issue, ADT Pro would return a write-protect error.

 

Your disk drive is not recognizing track zero.  I'd suspect quite highly that the diskette itself is damaged.  That's the error that ADTPro returns when it can't read back the diskette in the drive.  The likely cause is physical damage on track zero - see my explanation on surface mould.

 

Incidentally, why are you running ADTPro v 1.2.6?

I find that v2.0.1 works really well under XP, but run the latest version 2.1.0, if your host computer is on Win-10.

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i really dont think its the

Your disk drive is not recognizing track zero.  I'd suspect quite highly that the diskette itself is damaged.  That's the error that ADTPro returns when it can't read back the diskette in the drive.  The likely cause is physical damage on track zero - see my explanation on surface mould

 

i really dont think its the disks, the NOS disks i have are sony and they were shrink wrapped before i opened them. i also checked the disks themselves for any phisical issues like mold and found nothing.

 

also both drives read disks fine, dont they have to recognize track zero to read disks.

 

the oregon trail disk is a new reproduction i got off ebay and it wont write to that disk either.

 

when i first got the IIc and took it apart the motherboard was covered in some black stuff like it had been in a metal shop for years or in a fire so i wouldnt rule out one if the chips being bad.

 

Incidentally, why are you running ADTPro v 1.2.6?

 

i was trying diffrent versions of ADTpro to see if that was the problem but it obviosly wasnt

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Interesting. How about trying

Interesting.

 

How about trying to boostrap your IIc with DOS 3.3?

Those utility mini-programs in the Sams guide are DOS 3.3 based anyway.

And once you have DOS 3.3 in memory you can attempt to format your own disks using the "INIT HELLO" command, plus you can then do read/write tests and speed tests from the Sams troubleshooting guide.  Or write some read/write utilities in BASIC, or try to SAVE a progrma to disk.  (assuming you're able to initialize the diskette)

Without DOS and BASIC running you're stuck in ADTPro "jail".

 

Just run ADT Pro on your Windows PC and on the PC side use the "send esDOS" opti0n.  The user guide for that is here: https://www.adtpro.com/bootstrap.html#Bootstrapping_DOS

Scroll down to the DOS 3.3 bit about halfway down the page.

 

p.s. I'm also suspecting something wrong with either the 74LS125 that selects "write" or the CA314BE write amplifier.

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How about trying to boostrap

How about trying to boostrap your IIc with DOS 3.3?

 

your right, i will try this later. i thought there was a way to boostrap other programs with ADTPro but i guess i got tunnel vision and didnt realize i could load DOS to memory.

 

i will try this tonight and let you know the results.

 

can i bootstrap other programs or just ones built into ADTPro

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so no luck formating a disk

so no luck formating a disk in DOS. i get "DISK ERROR I/O"

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Try the external port

I've been thinking a lot about this.  You issue is strange yet I've experienced the same fault with ADTPro (but in my case it was bad diskettes).

 

It would be crappy if it were a motherboard problem as all the disk drive port signals run back to the IWM chip.

 

If this were me the next thing I'd try is to hook a drive up to the external port.  I believe that the internal drive is basically a standard Disk-II compatible drive with a 20 pin connector.  If that's the case make an adapter with some breadboard jumpers and plug your spare drive into the external drive port.

Then try your formatting experiment again.  

Assuming that the probability of BOTH drives being faulty is low to very low you can trace problems back this way and eliminate things like the ribbon cable, and the internal connector.

 

If it is a bad IWM chip they don't just come up for sale on eBay but I think you can swipe one from an otherwise dead Mac Plus motherboard. 

 

The guide for making an adapter is here:

https://www.applefritter.com/files/2021/02/10/Open-Apple_v1_n11_1985-12.pdf

 

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I would not suspect the IWM.

I would not suspect the IWM. It is a either a drive analogue board issue, or the write protect detection circuit for the drive has a fault. IWM failure would normally result in nothing working, not an error that is handled by the Disk //c analogue board I/O.

 

Check, and reploace these components on the Disk //c analogue board, in order:

 

74LS125

CA3146

MC4370

UNL2003

 

FWIW, I find that the 2003 and 74LS125 are the most likely to fail.

 

If all of those chips test good (or known-good chip replacement fails to fix this), then check the write protect window itself.

 

You can bypass write-protection entirely, but I do not advise doing that.

 

 

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Timelord wrote:I would not
Timelord wrote:

I would not suspect the IWM. It is a either a drive analogue board issue, or the write protect detection circuit for the drive has a fault. IWM failure would normally result in nothing working, not an error that is handled by the Disk //c analogue board I/O.

 

 I didn't think so either.  The IWM is pretty reliable.  But since he had the same failure across two drives, the logical course of action is to start checking motherboard issues.

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the write protection circuit

the write protection circuit on the original drive is bypassed and the circuit of the second drive is working correctly (pin 3 of IC 4B goes low when the drive attempts to write) so im pretty sure that the write protection circuit is not the issue.

 

i checked UD2 to see if pin 21 was going low when running the basic program in the SAMS book and it is high whether the program is running or not also it doesnt matter if the disk is write protected or not its high all the time. (im not sure if this is correct, the book doesnt say)

 

right now im kind of stuck because of the missing page from the SAMS that has the "Will Not Read" program, without that program i can not perform the rest of the tests in the book to narow down what circuit the problem is in.

 

im going to try and wire a drive to the external port to see if that changes anything altough i dont think it will since they share all but one wire of the circuit from what i can tell.

 

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