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Timkorbs

PHP 1250 NOT READING OR WRITING

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So I had a TI994a and tape drive as a kid, but recently, for nostalgia's sake, decided to buy a TI994a with a PEB and try to use disks. When I started to use the system a week ago, it would read disks, but it was having trouble writing and I only got it to save a file once. Now, it will not read or write at all. The disk system is moving and making some sounds (but not the reading sound I heard before), I have tried cleaning all the contacts in the cards and I opened the drive and cleaned the head, but it looks totally pristine in the PHP1250 drive and the drive head was super clean. Any ideas of what I could try?? I also unplugged and re-plugged in all the connectors in the drive to no avail. The firehose cable looks really good also and I dont see any obvious reason why a wire would be bad in there, but who knows. Any thoughts? I am a newbie for sure. Error 56 and 66 are what I see a lot. Thanks for thoughts!

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5.25 disks are probably old, just like the 99/4A. Some HD floppies won't work as well as the DSDD types. Not sure what you're using, but another thing to look at while trying to chase it down. Were these disks already initialized with files on them? How many have you tried?

 

Always possible something got scrambled on the disk when a write went south. Can you reformat one to try it fresh? You need a disk manager cart or program on disk.

 

I had a problem with the LED that detects if the disk's write-protect notch is covered. Wasn't dirt, the LED itself went bad.

 

Another guess that also gave me trouble if I forgot about it, if the drives are uncovered and the room lights are bright, that can mess with the sensors too. Toss a cardboard cover over it or try with the lights down. If the drives are in enclosures, that's probably not it. Since you're testing, I figured it's possible you have it laying out exposed to room lights.

 

Could try very lightly lubing the rails the head moves on.

 

Usually when I have a drive problem, I just pull out another one from my TI hardware stash and carry on. I have a few I swapped out that need looked at now. Running low on spares... ;)

-Ed

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If the data is safe to lose, you could also try reactivating the iron oxide in the diskettes/break up the domain boundaries, by subjecting the diskettes to a degaussing wand/bulk eraser.

 

That would remove any bias the coating has developed from storing a pattern for a very long time, and make it more useful again after a good format.  Did that with a few of the 360k IBM PC diskettes I inherited. (they had attenuated so bad from sitting for 40 years, that the data was not recoverable-- so I reformatted them. Most were fine. Some that showed 0 signs of media damage insisted they had bad sectors after a format with aggressive test-- so I degaussed them a few times, then formatted them. Work just fine now.)

 

 

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The epoxy layer on drive heads can wear down over time from friction. I have a couple of DSDD TEAC drives, both of them scrape the oxide layer off of the disks, leaving clear, see-thru tracks on the disks. Needless to say this permanently damages the disks/data. I was told by the rather well-experienced giver that this would happen relatively soon, as they had seen much use. I've always imagined I would restore these myself, perhaps with some LOCTITE 242, 271, or 272 thread locker. I doubt I ever will though.

 

I dug-up a couple decent pics...

unnamed.jpg.f462dee5c008ade99dce899c206eb9fd.jpg

Epoxy layer removed... Scrape!:-o

Untitled.thumb.jpg.9ff4f68302cc4d025828e4b0e32d4524.jpg

 

This page has some useful info too...

 

http://www.retrotechnology.com/herbs_stuff/drive.html

 

Several repair videos are available on YouTube.

 

 

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Indeed! This problem ^ is why I specifically mentioned that I inspected the disk media to check for signs of such wear, and found 0 signs of it, in my case-- which is why I considered the issue to be likely caused by incorrect coercivity of the media, from large domains forming.  (and why blasting it with a randomizing, high power magnet with oscillating flux, could potentially fix it.)

 

You should ALWAYS be listening for sounds of scratching, scraping, and such when the media spins-- AND, you should regularly inspect the mylar surfaces of your disks to ensure that no scrape marks are on it.  Once the oxide layer starts getting scooped off like icecream, the particles can accumulate inside the dust sleeve of the disk, further damaging the media-- also, the abrasive particles sand-paper the epoxy coating on the disk head, further damaging the disk drive.

 

Always examine diskettes for physical signs of wear, then address accordingly.

 

Again, in my case, there were 0 signs of such wear, so I explored other potential sources of media reliability issues. 

 

------

 

Concerning the video and the bearings he has:

 

I would personally have submerged the bearings in isopropyl alcohol, and spun them while submerged, to help remove the old crud from the inside of the bearing assembly.  Often, once those seals fail, dust contamination is INEVITABLE.  The seizure is really from the dust gluing the bearings to the bearing race inside, and forming a thick tar-like goop.  Cleaning that crap out is necessary to properly restore the bearing.  It will move and sound SOOOOOOOOO much better after a thorough cleaning like that, than it will if you just relube it and move on. I find the same issue often is the culprit for failed ball-bearing fans.  You can often revitalize such fans and get several years of hard use out of them before they get noisy and awful again, after a good cleaning like that. (Eventually, the cumulative impacts of the dust infiltrations will cause pockmarks on the balls and the bearing race, as the particles promote irregular surface wear, and corrosion, which you cannot fix.) Once cleaned and dry, I would give them a slight shot of deoxit, allow to dry once more, THEN lubricate with a quality synthetic lubricant.

Edited by wierd_w
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Those Bearings have numbers stamped on them so easy to get replacements.

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Thank you for the help. I watched the video and have made some progress by rotating the stepper motor a bit and it has started reading my disks! For some reason I still cant save anything though??

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There is a notch on the top right corner of a floppy. If that's covered, the disk is write-protected. That, or the write-protect sensor in the drive is faulty.

 

Next, if that seems to be ok, is there room on the disk for your additional file(s)?

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6 hours ago, Ed in SoDak said:

There is a notch on the top right corner of a floppy. If that's covered, the disk is write-protected. That, or the write-protect sensor in the drive is faulty.

 

Next, if that seems to be ok, is there room on the disk for your additional file(s)?

Yep, I've definitely checked that. There is room also. Weird thing is I tried to save a small basic file on like 5 different good disks and it ruined the data on all of them because now I can't catalog any of them and they don't run the files that were on them! What the??? I have tried formatting disks and that wont work either...It starts to format for about 20-30 seconds and then says "Disk Error"????? However, like I said, I can read disks now, but read them only.

Edited by Timkorbs

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On 10/22/2020 at 3:39 AM, wierd_w said:

If the data is safe to lose, you could also try reactivating the iron oxide in the diskettes/break up the domain boundaries, by subjecting the diskettes to a degaussing wand/bulk eraser.

 

That would remove any bias the coating has developed from storing a pattern for a very long time, and make it more useful again after a good format.  Did that with a few of the 360k IBM PC diskettes I inherited. (they had attenuated so bad from sitting for 40 years, that the data was not recoverable-- so I reformatted them. Most were fine. Some that showed 0 signs of media damage insisted they had bad sectors after a format with aggressive test-- so I degaussed them a few times, then formatted them. Work just fine now.)

 

 

Gonna get a degaussing wand and try that, thanks!

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On 10/22/2020 at 7:48 AM, wierd_w said:

Indeed! This problem ^ is why I specifically mentioned that I inspected the disk media to check for signs of such wear, and found 0 signs of it, in my case-- which is why I considered the issue to be likely caused by incorrect coercivity of the media, from large domains forming.  (and why blasting it with a randomizing, high power magnet with oscillating flux, could potentially fix it.)

 

You should ALWAYS be listening for sounds of scratching, scraping, and such when the media spins-- AND, you should regularly inspect the mylar surfaces of your disks to ensure that no scrape marks are on it.  Once the oxide layer starts getting scooped off like icecream, the particles can accumulate inside the dust sleeve of the disk, further damaging the media-- also, the abrasive particles sand-paper the epoxy coating on the disk head, further damaging the disk drive.

 

Always examine diskettes for physical signs of wear, then address accordingly.

 

Again, in my case, there were 0 signs of such wear, so I explored other potential sources of media reliability issues. 

 

------

 

Concerning the video and the bearings he has:

 

I would personally have submerged the bearings in isopropyl alcohol, and spun them while submerged, to help remove the old crud from the inside of the bearing assembly.  Often, once those seals fail, dust contamination is INEVITABLE.  The seizure is really from the dust gluing the bearings to the bearing race inside, and forming a thick tar-like goop.  Cleaning that crap out is necessary to properly restore the bearing.  It will move and sound SOOOOOOOOO much better after a thorough cleaning like that, than it will if you just relube it and move on. I find the same issue often is the culprit for failed ball-bearing fans.  You can often revitalize such fans and get several years of hard use out of them before they get noisy and awful again, after a good cleaning like that. (Eventually, the cumulative impacts of the dust infiltrations will cause pockmarks on the balls and the bearing race, as the particles promote irregular surface wear, and corrosion, which you cannot fix.) Once cleaned and dry, I would give them a slight shot of deoxit, allow to dry once more, THEN lubricate with a quality synthetic lubricant.

Well, after messing around a lot, I'm thinking it's either that I have a failing floppy controller card or a power supply issue, or both I suppose. The PEB I have is in really good condition. Everything looks super clean including the internals of the floppy drive. I can tell this thing has not been used much. My most recent attempt at fixing this was to order a different floppy controller card as it seems as though the symptoms could relate to that being bad. It's still being shipped to me now, but I'll drop a note in here as to whether it fixes the problem or not. As a kid, I had a TI and a tape drive, but I'm new to the peb. I'm definitely learning as I go! Thanks for the thoughts.

Edited by Timkorbs

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So I got my new floppy controller and that solved the problem of the drive not reading. The drive was also continuously turning on and off and that stopped that issue as well. My issue now is that I cannot write to a disk. I can't format and I can't save anything to discs. has anybody ever had a problem where their floppy drive would read but not right?

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Has there been any progress on this one? If not, you may have a broken wire in the cable between your floppy controller and the drive.

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On 11/4/2020 at 7:06 PM, Timkorbs said:

So I got my new floppy controller and that solved the problem of the drive not reading. The drive was also continuously turning on and off and that stopped that issue as well. My issue now is that I cannot write to a disk. I can't format and I can't save anything to discs. has anybody ever had a problem where their floppy drive would read but not right?

Is it an optical or mechanical detect for the read/write notch?  

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On 11/4/2020 at 8:06 PM, Timkorbs said:

So I got my new floppy controller and that solved the problem of the drive not reading. The drive was also continuously turning on and off and that stopped that issue as well. My issue now is that I cannot write to a disk. I can't format and I can't save anything to discs. has anybody ever had a problem where their floppy drive would read but not right?

Sorry, missed seeing this back in November.


What are you using to format a new disk or reformat an old one? The TI Disk Manager I or II cart is needed unless you have software on floppy and either of the Extended Basic or editor/Assembler carts. Your earlier replies sound like you have something that should work.

 

If you have a working floppy to experiment on, you could try loading one of the programs with OLD DSK1.NAME and using SAVE DSK1.NAME to save it back. Replace NAME in my example to whichever program you tried.

 

I read above a ways that you adjusted the stepper motor, this may be having an effect on things. And inspect the cable as Kasurl suggests.

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Hello, I have the same exact issue as Timkorbs, clean PEB that will read and run disks fine, but cannot write.  I’ve cleaned all contacts, reseated the cards, swapped the flex slot from 1 to 2 as mentioned in the thread “let's chase some ghosts” but still no dice.

  • When trying to save a basic program I get “I/O Error 66” (Save Error)
  • When I try to format a disk, it sounds promising (the head clicking through the tracks) but after a time I get “Disk Error 31” (Record not found on input)
  • Disk Manager 1.0, Destructive quick test produces failures in turn, I finally stopped it after 40+ errors

I suspect that the write head is doing nothing? because when I broke down and tried to re-format a known working disk I still got Error 31, and to my surprise the disk was perfectly fine afterwards (I expected the data to be wiped out.)

 

@Timkorbs did you ever find a solution?

@Ksarul you mentioned a broken wire, is that something I can check?

 

Thanks

 

p.s. I have two disk controllers, and I’ve tried with both.  Same behavior.
 

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Looks like you have one of two possible problems: a bad cable between the disk controller and the disk drive OR a bad drive (the write head or its circuitry isn't working). Since you get a good read on existing disks, I would suspect the drive more than the cable, but the cable pins you really need to keep an eye on are pins 22 (write data), 24 (write gate), and 28 (write protect). If all three of those wires test good (look for damage in that part of the cable, as it is sometimes extremely visible and use a meter to check each of the wires in that area end to end), the problem is more likely to be a problem in the drive. Do you have a second drive you can test with?

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34 minutes ago, Ksarul said:

Looks like you have one of two possible problems: a bad cable between the disk controller and the disk drive OR a bad drive (the write head or its circuitry isn't working). Since you get a good read on existing disks, I would suspect the drive more than the cable, but the cable pins you really need to keep an eye on are pins 22 (write data), 24 (write gate), and 28 (write protect). If all three of those wires test good (look for damage in that part of the cable, as it is sometimes extremely visible and use a meter to check each of the wires in that area end to end), the problem is more likely to be a problem in the drive. Do you have a second drive you can test with?

Thanks for the tip Ksarul!  Gives me somewhere to start.  I'll check the cable closely and possibly try to hook up a logic analyzer to those signals. By a "second drive" I'm assuming you mean another TI drive?  Or can PC compatible 5 1/4 drives be hooked up as well?  I'll have to research that one.

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if your cable is more than 30 years  old, maybe replace it? I have new cables in my store ribbon cables and edge connectors don't last forever

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18 minutes ago, arcadeshopper said:

if your cable is more than 30 years  old, maybe replace it? I have new cables in my store ribbon cables and edge connectors don't last forever

Thanks arcadeshopper, I just tried another straight-through floppy cable I have and same behavior, the edge connectors look good, I'll keep checking...

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Could very well be the capacitors or other components on your drives as well I've seen some of the older full height drives just refuse to write..

Also the write protect switch or led could be bad I've seen those go bad over time or get mail adjusted use a meter and see if they're making contact like they're supposed to

Sent from my Pixel 6 Pro using Tapatalk

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2 minutes ago, arcadeshopper said:

Could very well be the capacitors or other components on your drives as well I've seen some of the older full height drives just refuse to write..

Also the write protect switch or led could be bad I've seen those go bad over time or get mail adjusted use a meter and see if they're making contact like they're supposed to

Sent from my Pixel 6 Pro using Tapatalk
 

Good points, I'll check what caps I can.  There are I/O and Disk error codes for Write Protected? Doesn't hurt to check though.

 

I know these have been posted many times before, but I'll put them here for reference:

 

I/O Errors:

image.thumb.png.92d9109d98e2e1e985834b9394125f7a.png

 

Disk Errors:

image.thumb.png.958e584976757b0e8676979eb4ded2f3.png

 

 

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Close visual inspection turns up nothing obvious, ESR says caps are within bounds and no evidence if leaking.  Troubleshooting this thing electronically feels a bit intimidating.  Guess I'll start searching for theory of operation, troubleshooting guides, schematics and the like.  I noticed the Section 12 of the PEB Tech training guide has some stuff in there.

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Posted (edited)

Is the drive in an enclosure or out and exposed on top? How strong is your room lighting? I have found strong light on a bare drive can overpower the write protect LED and sensor, causing errors. Just dimming the lights or placing a cardboard cover over the drive returned it to normal operation. I have also seen a failed LED or sensor, only once though.

 

Edit: I see I said all this in an earlier post to this thread. Doesn't hurt to repeat it though.

Edited by Ed in SoDak
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Note, the error would be 61 if the Write Protect sensor isn't working. Your problem is probably with the ability of the head to write (or in this case, lack of that ability).

 

On PC drives in place of TI drives, the answer is: it depends. HD drives (1.2M) do not work with the TI, but DD (360K) drives work fine. Stay away from 3.5 inch drives for now (they can be used, but there are a lot of quirks to be aware of when doing so). The combinations drives (a 5.25 and a 3.5 in the same housing with a single half-height faceplate) almost never work with a TI and should be avoided.

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