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Ibm 4869 1.2mb

S

stangman517

Experienced Member
Joined
Dec 15, 2014
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243
Location
Georgia, USA
Greetings all.

Ok I'm about to give up on getting one of these 5 1/4 drives that work. I received another today and no workee! The seller said it was in his late fathers' collection and was never used. When I took it out of the box, no original box, and plugged it in nothing happens. The drive in use light doesn't blink or nothing. The unit looks NEW. I took the cover off and put a multi-tester on the power connector from the PS into the various pins and got readings of 5V and 12V. I understand this is a good thing??? Someone had me do this to another drive once before. Does this indicate the PS works and the 5 1/4 drive doesn't???

I have Coleco ADAM and Commodore drives I can plug in and the power light stays on and the drive in use light goes out after a few seconds, but nothing on this new one. At least the other one I bought the led twinkled on and quickly off.

Does anyone know the typical behavior of these drives? Should the led stay on with power to it and then goes off after the PC is fired up? I plugged it into my Mod 57 with a controller card (FRU 15F7996) and the led on the drive twinkled this time but quickly and then NOTHING. OS/2 should see it like any floppy drive.

Anyone know someone that repairs these guys? Do they have some sort of inherent hardware problem?

Thank you!
 
I've been servicing floppy drives for getting close to 40 years.

It's possible that the problem is not with the drives you've been getting, but rather the way that the jumper plugs on the drive are configured, or the cable that you are trying to connect them to the computer with.

It's also possible that the disk controller is bad, or the drive is bad.

At this point there are too many possibilities. You need to start with parts that work, and sub in your parts one by one until you narrow/eliminate the possibilities.

Start with a computer that has a working 1.2mb floppy that you can plug yoour drive and data cable into to test them. If the drive and cable work on the other computer, then your computer or disk controller, or power supply have a problem.
 
MicrocomputerSolutions said:
I've been servicing floppy drives for getting close to 40 years.

It's possible that the problem is not with the drives you've been getting, but rather the way that the jumper plugs on the drive are configured, or the cable that you are trying to connect them to the computer with.

It's also possible that the disk controller is bad, or the drive is bad.

At this point there are too many possibilities. You need to start with parts that work, and sub in your parts one by one until you narrow/eliminate the possibilities.

Start with a computer that has a working 1.2mb floppy that you can plug yoour drive and data cable into to test them. If the drive and cable work on the other computer, then your computer or disk controller, or power supply have a problem.
Click to expand...
While that's a great approach for most situations it's kinda tough to apply that scenario to an external, proprietary floppy drive.
 
stangman517 said:
Does anyone know the typical behavior of these drives? Should the led stay on with power to it and then goes off after the PC is fired up? I plugged it into my Mod 57 with a controller card (FRU 15F7996) and the led on the drive twinkled this time but quickly and then NOTHING. OS/2 should see it like any floppy drive.

Anyone know someone that repairs these guys? Do they have some sort of inherent hardware problem?

Thank you!
Click to expand...

I'd imagine the IBM external floppies are just like internal floppies connected via an external cable. So the behavior should be just like an internal drive, I.E. applying power doesn't make the drive do anything. The system BIOS self test causes the floppy to light up and seek the head during bootup, it's not built into the drive itself.
 
I had a lot of trouble trying to get my 5.25 floppy to run on my 486 and on my Celron running XP. Turned out in the end I was unlucky enough to have one bad drive and 3 bad cables. It's worth spending a fiver on a brand new floppy cable from eBay (or the like). They seem to be the 'weakest' component in my experience. It's also worth noting, that after a new cable my drive from 1981 worked like a dream once I'd set it up in BIOS. Hope this helps.
 
I've used 4869 boxes for most things floppy for a long time (at least 20 years). I've still got a few NOS, but the last one I tried to sell, the guy's check bounced and he vanished. I was on the hook for shipping and the item. If he ever shows up on this forum again, I'm not going to let him forget it.

The 4869 cable is wired a bit differently for use with most "normal" controllers that have a DC37F external drive connector. I've written about it on my blog; a search should turn that up. From what I recall that 4869 was made for use with a Diskette Adapter/A card and the plug wiring pretty much confirms that.
 
Hello MicrocomputerSolutions

Early today I found a comment where the technician writes => " Static tests of a power supply don't tell what it will do when
loaded with the drive. The +5VDC powers the chips and the +12VDC runs the motors." So by me testing the pins on the connector leading from the PS is what he's saying "Static tests," and the comments further suggest putting the unit under load - which I cannot if the drive doesn't get enough power from the PS. I am not a technician, but I can take the 5 1/4" drive out and test it in one of my other IBM systems. If it works then I know unequivocally it's the PS. Does this sound logical?

I can't tell if the drive has ever been opened. It's got a six phillips screws and two star screws with a pin RIGHT in the center of it; never seen this before, so my star bits didn't work; I had to use a tiny flat head to open it, so haven't looked at the back of the drive yet. Also I do not have another controller. Though the system configured (Mod 57) correctly with the ADF are you saying the controller could still be bad? Unfortunately I don't know of another IBM PS/2 to test it on.
 
Well I removed the 5 1/4" disk drive and hooked it up to my 486 system. During post the system detected it, I then formatted 1.2MB and 360K diskettes, and copy/read files to a diskette with no hiccups. I think it's safe to assume the PS is bad. Does anyone know where to get a replacement PS or know where to get the guts to replace what's inside it now?

Thank you for everyone's comments!!!!
 
FWIW, if you're concerned about the PSU, just power the thing on and insert a floppy while listening carefully. If you hear the drive motor come on for a second or so when you latch the door, your power supply's fine. The PSUs in these things are very conservatively rated--not enough to power a hard drive, though. I've yet to see one fail.
 
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