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IBM 4869 1.2 Meg Version

lyonadmiral

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Has anyone any experience in troubleshooting failures with these external drive units? I picked one up a few weeks ago with the controller card. Doesn't seem to have power. Usually when I powered up a unit like this, the light of the floppy disk would flash/flicker once, but this one does nothing.

Chuck, if you're reading this, you still have any of those empty cases lying around? :D
 

IBMMuseum

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Has anyone any experience in troubleshooting failures with these external drive units? I picked one up a few weeks ago with the controller card. Doesn't seem to have power. Usually when I powered up a unit like this, the light of the floppy disk would flash/flicker once, but this one does nothing.

I'm interested to which "controller card" you have. The 360Kb (4869-001 or 4869-501, with an asterisk on the drive faceplate) drive clunks when doing a disk access. You could check the power inside, even to have a substitute supply.

4869-002 is the model number for the 115V power supply - the 4869-502 is the 220V unit. The drive would have the same behavior if it is in a system - access LED flickering with power on, so an unknown factor between different possible drives - but typically a flicker, I agree. The page needs a little editing and is redundant with another purely on the controllers: https://ardent-tool.com/floppy/4869-002.html
 

lyonadmiral

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I'm interested to which "controller card" you have. The 360Kb (4869-001 or 4869-501, with an asterisk on the drive faceplate) drive clunks when doing a disk access. You could check the power inside, even to have a substitute supply.

4869-002 is the model number for the 115V power supply - the 4869-502 is the 220V unit. The drive would have the same behavior if it is in a system - access LED flickering with power on, so an unknown factor between different possible drives - but typically a flicker, I agree. The page needs a little editing and is redundant with another purely on the controllers: https://ardent-tool.com/floppy/4869-002.html

I have the 90X8827/72X6757 branded controller. I've watched some videos on YouTube today, My Messy Lab where he took apart the power supply and tested it, I didn't finish the video for a couple of reasons, I could test it if I got it apart (maybe) but I certainly don't have the fine motor control to do fixes anymore.

I unplugged the data cable from the controller, tried powering on the drive on/off, off/on, no flicker in the lights, so I wonder if perhaps this PSU has a critical failure.
 

Chuck(G)

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The PSU does have a fuse on the PCB, but you'll need to drill out the rivets on the PSU cage to get to it. In at least 2 of my units, I replaced the PSU with a beefier one when I wanted to run SCSI devices--the original didn't have the capacity to support, say, a SCSI CD-ROM drive.
 

IBMMuseum

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I have the 90X8827/72X6757 branded controller.

8-bit bus for the Model 30? That doesn't support the 4869-002. It's a pass-through adapter that uses the system's B: drive connection. I don't believe the adapter itself is diagrammed at the Ardent-Tool, although I have pictures and have dumped the EPROM in a disorganized way at http://ibmmuseum.com/Adapters/

For anything conventional, you will need to go microchannel with a 15F7996 ("Diskette Adapter/A") controller. There is also an older pass-through design for microchannel that also only supports the 4869-001 (360Kb) as well. No asterisk embossed in the drive face? The 4869-002 are fairly uncommon, although it is an easy drive swap from a 4869-001 - No idea why it was paired with the Model 30 adapter, but someone could have failed to make a go of it for that reason, and just wanted to sell it off.
 

lyonadmiral

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8-bit bus for the Model 30? That doesn't support the 4869-002. It's a pass-through adapter that uses the system's B: drive connection. I don't believe the adapter itself is diagrammed at the Ardent-Tool, although I have pictures and have dumped the EPROM in a disorganized way at http://ibmmuseum.com/Adapters/

For anything conventional, you will need to go microchannel with a 15F7996 ("Diskette Adapter/A") controller. There is also an older pass-through design for microchannel that also only supports the 4869-001 (360Kb) as well. No asterisk embossed in the drive face? The 4869-002 are fairly uncommon, although it is an easy drive swap from a 4869-001 - No idea why it was paired with the Model 30 adapter, but someone could have failed to make a go of it for that reason, and just wanted to sell it off.

It came in a model 30, although now I get the feeling that maybe that is what happened is the person I bought it from just throwing things together and not realizing the nuances but I went through with the purchase anyway because in all my life (almost 40) I've never seen a 4869-002.
 

IBMMuseum

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I've watched some videos on YouTube today, My Messy Lab where he took apart the power supply and tested it, I didn't finish the video for a couple of reasons, I could test it if I got it apart (maybe) but I certainly don't have the fine motor control to do fixes anymore.

It's interesting that he has the 4869-002 - and talks about swapping it back to a 360Kb drive in the third video. He has a 4865 (external 720Kb) drive too. With the 15F7996 adapter, there is a rudimentary driver - I tested this stuff extensively years ago. Here is a video of mine showing the Model 30 adapter: https://www.youtube.com/watch?v=ATUFjPldvcg
 

Chuck(G)

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I don't believe that he's running it on a PS/2. You can run one with a 360K drive from a 5150 floppy controller (DC37 on the bracket) or from a number of third-party controllers. The instruction booklet packed with the drive indicates that the Diskette Adapter/A is appropriate.
 

IBMMuseum

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The instruction booklet packed with the drive indicates that the Diskette Adapter/A is appropriate.

It should be easy enough to adapt an internal diskette connection on the right system to run the drive - the SYSGEN "Bridge" designs did. The 15F7996 driver is simplistic and only allows a single drive on the internal and external connections. If there is a drive connected to each, the internal drive is assigned a drive letter first.
 

Chuck(G)

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Did you see my blog post back in 2010? Thanks to the new forum software, part 1 here part 2 is still around here. I got started in the 1990s by ordering a 30 cartons (3 drives per carton) of these back in the 1990s and putting Teac FD505 modified drives in them and shipping them with Compaticard IVs. I had a few cartons left over and still have one.
 
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IBMMuseum

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Did you see my blog post back in 2010? Thanks to the new forum software, part 1 here part 2 is still around here. I got started in the 1990s by ordering a 30 cartons (3 drives per carton) of these back in the 1990s and putting Teac FD505 modified drives in them and shipping them with Compaticard IVs. I had a few cartons left over and still have one.

I think I've seen that - the 15F7996 controller only recognizes one drive per each of the internal and external connections. On other adaptations, you can get past that.

It would be good to empirically test a 4869-002 with a Model 30 - The right 1.44Mb drives work there, and the controller should be able to run 1.2Mb. There isn't much code on the EPROM to have something more involved.

The 15F7996 driver could use some work too. Attached drives are identified as the 5-1/4" size. WBST worked on some angles with them.
 

lyonadmiral

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I don't believe that he's running it on a PS/2. You can run one with a 360K drive from a 5150 floppy controller (DC37 on the bracket) or from a number of third-party controllers. The instruction booklet packed with the drive indicates that the Diskette Adapter/A is appropriate.

I was trying to hook up an 8525 with an external 5.25... I had known there were potentially two versions of the external drive and I had known there were both ISA and MCA versions of the controller card but I didn't know there were two flavors of the MCA card, which unfortunately is moot for me since I do not have an MCA system.
 

lyonadmiral

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With all of this in mind, I now have a 4869-002 that I can't tell if it works or if it doesn't and wonder if anyone wants to swap for a 4869-001 or is interested in buying this?
 

IBMMuseum

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With all of this in mind, I now have a 4869-002 that I can't tell if it works or if it doesn't and wonder if anyone wants to swap for a 4869-001 or is interested in buying this?

Like Chuck(G), I have some 4869-001 units, even a couple that are disassembled - I am interested in a trade by getting you the functional 4869-001 items, be it complete (higher shipping costs) or just the drive and possible PSU. One of my Model 25s has a 4869-001 adapter (it was an internal IBM unit, and also has an AST board and personnel management software), so I will be able to test and supply an internal cable if needed.

Contact me by PM.
 

Chuck(G)

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Other than the drive itself, I wasn't aware that there was any substantial difference between the -001 and the -002; after all it's just a power supply and a cable if you ignore the drive. Heck, I even have a 3" CF2 drive installed in one, as well as 1.44M, 1.3M and 720K 3.5" drives. One even has a SCSI DDS2 drive installed.
 
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