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IBM PS/2 Model 25 not reading floppies

gleegum

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Hi,
I got this IBM PS/2 Model 25 Type 25-S01 that can't read floppies. Somebody installed a hard drive on it, but I had to remove it since it was not working.
I've cleaned the floppy read/write head with isopropyl alcohol, it was pretty dirty, also lubricated the rails, etc.

After the machine finish checking the RAM, the drive lights up the yellow LED and the motor spins, like trying to read a disk, but fails, and the computer shows a graphic asking for a disk (see pic).
Upon pressing F1 the machine starts BASIC.

I'm using DSDD 720k floppies, I know they're ok because I use them on my Amiga 500.
I've made the startup disk for the model 25xt using the program Teleget under MSDOS 6.22. I've recorded the image with WinImage too under WinXP 32bit.

I get the same result always, the drive doesn't read the floppy, it moves the head like searching for a track but then it goes back and nothing happens.

I see that this drive is not a generic one and I assume it's not easy or cheap to find one for this machine in working order right?
So, is there anything I could check on the drive? Maybe the caps are dried up? What are the most common components to fail on it?

Thanks!
 

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evildragon

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It's entirely possible the drive needs a recapping. These PS/2 drives electrolytics are starting to dry up. You did good on cleaning the heads and lubricating the rail, but beyond that, the caps are next.
 

ldkraemer

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gleegum,
Tekeget states that it uses .TG0 fliles. Where did you get the .TG0 file and was the file approximately 1.5meg in size. The floppy's are also supposed
to be 1.44 Meg Floppy's.

Larry
 

evildragon

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He does not appear to have a high density floppy drive in his model 25, so he is not supposed to use 1.4MB disks at all. He was correct in using double density disks. Also, Teleget would have given an error if the disk image wasn't sized correctly to fit the disk.
 

Chuck(G)

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There were various OEM versions of TeleGet produced, keyed to a vendor's specification. Believe me, if you have a mis-match, you'd know it. Teledisk, will handle garden-variety TD0 files.
 

gleegum

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Thanks for the replies.

I got the tg0 file and teleget program from this site http://www.walshcomptech.com/ps2/25startdisks.htm
It has a lot of resources for the ps/2.

Tg0 file is about 280kb, so I guess is a low density disk.
By looking at pictures online I think the drive in this PS/2 is not High Density, the HD one appears to have "1.44mb" written on the eject button.

I also used the Refstamp program with no luck.

Not sure if I can try a another disk? Maybe with DOS3.3?
Anyway, recapping as suggested is in my to-do list.
Thanks!
 

evildragon

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Thanks for the replies.

I got the tg0 file and teleget program from this site http://www.walshcomptech.com/ps2/25startdisks.htm
It has a lot of resources for the ps/2.

Tg0 file is about 280kb, so I guess is a low density disk.
By looking at pictures online I think the drive in this PS/2 is not High Density, the HD one appears to have "1.44mb" written on the eject button.

I also used the Refstamp program with no luck.

Not sure if I can try a another disk? Maybe with DOS3.3?
Anyway, recapping as suggested is in my to-do list.
Thanks!

I can verify without a doubt that the disk image from uxwbill works just fine. I downloaded it on my model 25, and even ran teleget on my model 25 to make the disk, it boots off it just fine. Yea your eject button will say 1.44MB if it is a high density drive (contrary to popular belief I have found the 25 IS high density capable, but was never sold as such---yours simply has a double density drive in which case the button had no label on it).
 

gleegum

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Thanks evildragon for the info, very helpful. gonna check those capacitors. I saw that it had 47uF and 10uf on the top PCB, I don't have the floppy drive with me right now, but I remember it had a couple of aluminium caps on the bottom PCB, do you know the value of those? I think thet were surface mounted. Gonna check them. Thanks!
 

evildragon

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I think only the electrolytics are the ones that need replacing, so I don't have the values of the ones on the bottom.
 

zombienerd

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I'll +1 to what most have said - it's a 720k drive, they're notorious to need re-capping.

I recommend finding a 1.44mb unit, they're a bit easier to find, cheaper, and tend to last longer. I found the Sony-made 1.44mb drive unit for my Model 25, and couldn't be happier. Look for Sony part number MFD-77W, or IBM part number 90x6766.

the 90x6766 is a generic PN for 1.44mb with the card edge, not all of them may work in your system, so try to find the Sony if possible.

Also, if anyone needs parts for the 720k drives, I have 3 broken ones... One was recapped, but did not work any better after recapping. The other two haven't been touched, but don't work.
 
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gleegum

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Floppy drive is working!
I've recapped the unit as suggested and now it works flawlessly.
The disk I've written with TeleGet works like a charm, I did a copy on the PS/2 just to test the drive.

What OS can I get for this system? MSDOS 3.3?

Thanks!!!!!!
 

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evildragon

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Awesome, glad to hear it worked! Yea those electrolytics are starting to go bad.

Run whatever you want on it, I run DR-DOS 6 on mine personally.. I also have a VGA card modded in mine with XT-IDE, and have Geoworks Ensemble 2.0 as well.
 

zombienerd

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Floppy drive is working!
I've recapped the unit as suggested and now it works flawlessly.
The disk I've written with TeleGet works like a charm, I did a copy on the PS/2 just to test the drive.

What OS can I get for this system? MSDOS 3.3?

Thanks!!!!!!

I run MS-DOS 6.22. Runs peachy. I also installed an XT-IDE card from Glitchworks. It's quite the fun little machine! Mine is color though :)
 

billdeg

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Came with DOS 3.3. Mine came with Windows 1.04 "Collegiate Kit" for dual drive 720K disk systems. Sat on top of DOS 3.3 as an application. This is the OS I used in college, the model 25 was my first computer. But run whatever works on an 80C88

Bill
 

evildragon

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Came with DOS 3.3. Mine came with Windows 1.04 "Collegiate Kit" for dual drive 720K disk systems. Sat on top of DOS 3.3 as an application. This is the OS I used in college, the model 25 was my first computer. But run whatever works on an 80C88

Bill

I think we've been over this before, but pretty sure the model 25 does not use an 80c88. ;) It runs on a bog standard 8086.
 

zombienerd

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I have Windows 3.0 running on my 25-004, iirc. Slow as dirt, but was fun to play with for a few minutes. I could only run it in CGA mode, couldn't find drivers for the MCGA.
 
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