Jump to content
IGNORED

IIc Plus 3.5" floppy drive problems/questions


spacecadet

Recommended Posts

Hey all,

 

I have a thread about this on AppleFritter too but I think I might actually get some better responses here. I have a IIc Plus that was broken when I got it and I'm in the process of restoring it to 100% functionality. At this point the only problem it seems to still have is the eject motor on the floppy drive being stone dead. It doesn't even try to eject disks. I've tested the eject switch, disk sensor switch, the motherboard pins, solder points and traces, and I've even looked at the gears on the motor that I know go bad over time (again, the motor is not even turning). I've ruled out everything I can think of other than the motor just being toast.

 

So I'm thinking I need to replace that motor one way or another. I'd like to keep the computer as close to original as possible. The drive otherwise works fine, so I'd love to replace just that motor, which is a common eject motor on a lot of Apple drives. So the first question is, can I just take that same eject motor (the Omron R2-DG38) out of, say, a IIGS or early Mac drive and drop it in to the IIc Plus and expect it to work? There is a circuit board attached to it, so I don't know if there are any differences in that for different computers. I just want to know what the minimum is that I'd need to do to replace that motor instead of the whole drive.

 

And the follow-up question is basically the same for the drive itself... could I, theoretically, buy an external 800K drive, remove the enclosure, and just drop the drive itself into the IIc Plus? I've seen people say it's the "same drive" in an external case, but I don't know if that means down to the location of the screw holes and cables and stuff like that. The IIc Plus's eject button, for example, isn't even wired to the drive but to the motherboard. I don't know how it's wired in the external drives, but I assume it's actually wired to the drive somehow.

 

Also, if anybody has a drive to sell, even a non-working one that has a working eject motor, or even just the motor by itself, I would be interested. I might place a WTB ad once I know what I actually need to do.

 

Thanks!

Link to comment
Share on other sites

I've replied to you a few times over on AF. This is not an uncommon issue. If you for some reason can't find another mech, and need it serviced, send me a note. These are the same mech as the //gs, some SEs, LCs, and Mac IIs. It must be a red stripe model to be compatible. 

Link to comment
Share on other sites

4 hours ago, GameGeezer said:

I've replied to you a few times over on AF. This is not an uncommon issue. If you for some reason can't find another mech, and need it serviced, send me a note. These are the same mech as the //gs, some SEs, LCs, and Mac IIs. It must be a red stripe model to be compatible. 

Yeah, it's red. I'm thinking to just get another drive and swap out the motor if that's possible. So any Omron R2-DG38 motor from a different drive would work?

 

None of the common problems are the actual problem, so I feel like I stopped getting responses at AF for that reason. It's not difficult to switch the motor but before buying something I'm just trying to make sure there's not some kind of drive identifier on the eject motor board or different wiring or anything.

Link to comment
Share on other sites

20 hours ago, spacecadet said:

Yeah, it's red. I'm thinking to just get another drive and swap out the motor if that's possible. So any Omron R2-DG38 motor from a different drive would work?

 

None of the common problems are the actual problem, so I feel like I stopped getting responses at AF for that reason. It's not difficult to switch the motor but before buying something I'm just trying to make sure there's not some kind of drive identifier on the eject motor board or different wiring or anything.

 

The eject motor is interchangeable between all SONY 51W and 75W mechanisms.  

 

Eject motors dying, was a common issue twenty years ago. I will note that anythin gbeyond surface level technical issues seems to go overlooked there; and whenever I find an issue beyond my own technical ability, knowledge and resources, it is unlikely that anyone there will know better, but I live in hope. 

 

Try a continuity test on the eject wiring from the solder pads on the analogue board, to the solder pads on the motor. It isn't terribly rare to see a wire in that tiny connector fail a continuity check from one pad to the other pad. If any of them fail, first reflow the pads on both sides. 

 

OTOH, if they all pass continuity between the *pads* on both PCBs, then one of the following is the likely issue:

 

1. Bad motor.

2. Damaged traces on motor PCB.

3. Damaged traces on analogue board.

 

In any case, if you have another drive, you want to test that inside the //c+ first, or if you have a //gs 3.5 Drive case, you can try the drive mech inside of that. Ideally, you want to verify and confine the fault to either the mechanism or the //c+ logic board.

 

If you wish to discuss this further on Discord or IRC or something, I can do that, but I am acting under the general belief that you have the tools and knowledge to perform these tests. 

 

I don't want to see you throwing money at another mechanism if the actual drive mech eject motor is good. If you own a Mac II series system, or an SE, and its drive cable is a red stripe, you can swap out the raw mechanism, and test if it ejects disks using System 6 or 7. 

 

Please inform me of what equipment you have on which you can test the drive, and if you need any further information to perform any validations. 

Edited by GameGeezer
Link to comment
Share on other sites

1 hour ago, GameGeezer said:

If you wish to discuss this further on Discord or IRC or something, I can do that, but I am acting under the general belief that you have the tools and knowledge to perform these tests. 

 

I don't want to see you throwing money at another mechanism if the actual drive mech eject motor is good. If you own a Mac II series system, or an SE, and its drive cable is a red stripe, you can swap out the raw mechanism, and test if it ejects disks using System 6 or 7. 

 

I *probably* have the tools and knowledge :) But I'm not all that experienced at it, and definitely not in dealing with motors. I usually just replace them.

 

I should be able to test the solder pads on the analogue board and motor board and reflow them if anything doesn't have continuity. I guess that's really my last resort before replacing stuff. I'll try that tomorrow.

 

I *had* two IIGS drives before I moved a year ago and I haven't seen them since. It's driving me crazy and I've been turning my garage and closets upside down looking for them. They may be gone so I'm hunting Ebay right now for a decent deal (I need one for my IIGS anyway, and even if I swap the eject motor for the bad one I have, the drive will still work... I'd rather the IIc+ be fully working with auto-eject than an external 3.5 drive). Unfortunately I believe in that same box with the drives is my "good" multimeter! I have a crappy one that I started out with, at least, but I am so annoyed if I lost all this stuff while moving...

 

The only Macs with 3.5" drives that I have are later ones, unfortunately; a Performa 476 and some kind of early PowerMac. So I will need to buy a drive if the soldering of the wires checks out. I'm not confident in being able to repair broken traces if that's the issue. Soldering I can do.

 

Thanks for your help so far!

Edited by spacecadet
Link to comment
Share on other sites

3 hours ago, spacecadet said:

 

I *probably* have the tools and knowledge :) But I'm not all that experienced at it, and definitely not in dealing with motors. I usually just replace them.

 

I should be able to test the solder pads on the analogue board and motor board and reflow them if anything doesn't have continuity. I guess that's really my last resort before replacing stuff. I'll try that tomorrow.

 

I *had* two IIGS drives before I moved a year ago and I haven't seen them since. It's driving me crazy and I've been turning my garage and closets upside down looking for them. They may be gone so I'm hunting Ebay right now for a decent deal (I need one for my IIGS anyway, and even if I swap the eject motor for the bad one I have, the drive will still work... I'd rather the IIc+ be fully working with auto-eject than an external 3.5 drive). Unfortunately I believe in that same box with the drives is my "good" multimeter! I have a crappy one that I started out with, at least, but I am so annoyed if I lost all this stuff while moving...

 

The only Macs with 3.5" drives that I have are later ones, unfortunately; a Performa 476 and some kind of early PowerMac. So I will need to buy a drive if the soldering of the wires checks out. I'm not confident in being able to repair broken traces if that's the issue. Soldering I can do.

 

Thanks for your help so far!

 

Any 5VDC circuit tester will work. Even the cheapest gauges have that capacity.

 

I would avoid eBay and look at the Apple Ii and Mac suppliers websites. They will have better pricing, and the drives will be properly serviced. Most of the drives on eBay are both overpriced, and sold by people who have no clue how to repair them, or to test them. 

 

I can probably test some eject motors this coming week and find a good one for you, but again, we have no isolated that as the only issue here. 

 

As long as you are still in a state of flux with that drive, test that it reads and writes disks with manual eject. If the analogue board is bad in general, then it isn't worth repairing it at all, as that component (singly) will cost as much as, if not more than, a complete mechanism.

 

On another note, on eBay, search for Mac 800K drive mechanism (SONY FP-F51W). Look for anything with a black 51W sticker on it, and if it has a cable, note if it has a yellow stripe. The yellow stripe drives are for some Mac Plus models, and they have a slightly different signal to the eject assy, that will cause them to constantly try to eject disks on anything other than the Mac Plus mainboard. IDR if that is something that can easily be changed. (I barely remember that it was a thing.)

 

Anecdote:

 

I am not suggesting to buy this, but I wanted to provide it as a general proof that eBay sellers have no clue what they are selling:

 

https://www.ebay.com/itm/Macintosh-1-44-Sony-Drive-MP-F51W-Tested-And-Working/274350331819?hash=item3fe08dd7ab:g:fIUAAOSwEwpeqFkg

 

That is not a 1.44MB mechanism! It's a 51W, an 800K drive; and this tells me that the seller's idea of 'testing' the drive is suspect! The 75W is 1440K, and it has a blue sticker with '2MB' on it. (No, the //c does not have the SWIM chip, so you can't use a 75W at full capacity, but a 75W will work as a 51W at 800K capacity, internally.)

Edited by GameGeezer
Link to comment
Share on other sites

11 hours ago, GameGeezer said:

As long as you are still in a state of flux with that drive, test that it reads and writes disks with manual eject. If the analogue board is bad in general, then it isn't worth repairing it at all, as that component (singly) will cost as much as, if not more than, a complete mechanism.

I did test that the other day; I took the System Utilities disk from my Floppy Emu and used it to copy itself to a blank disk on the internal drive. Writing and then reading the disk back worked fine. Actually every time I do anything with the eject motor now I've been testing with that disk afterwards just to make sure the drive still works and I didn't mess up anything else. It's a fully functional drive other than ejecting.

 

Today I tested continuity of the wires to the motor itself and they *seemed* fine, although maybe you can verify for me how they're supposed to be connected, because I was getting cross continuity between red and brown wires in addition to each wire individually. Is that right? I looked at the soldering and I didn't see anywhere it seemed to be touching by mistake. It seems like a really simple straight soldering job so I don't even know how to fix that if it's not right, because I couldn't figure out why I was getting cross continuity.

 

As part of doing that, though, I also took the PCB off the motor just to look underneath and see if maybe there was solder there too (there's not; the wires just go straight through and are soldered only on top). And I saw how it seems like there are two metal posts with a set of "prongs" on one that act like a spring that's pushed out of the way by a cam on the motor gear when a disk is inserted. (That seems backwards but it looked like the only possible way it would go, unless my main gear is on backwards!) Is that the way this is supposed to work? One of those posts (the one with the prongs) seemed loose, although there was still continuity, but I re-soldered that so it's securely in place. Still no change in the motor behavior, though.

 

But it did make me wonder about that because it seems like that's a really obvious failure point from simple metal fatigue, and I wonder if mine is still just out of place a little. It's impossible to see how it's actually going in when you put it back together. But how is that supposed to look? Should those horizontal prongs be in contact whenever a disk is *not* inserted, and then get pushed apart when a disk is inserted? It seems like it's supposed to know to stop running when that circuit is made. If that's correct then I doubt it's my issue because it seems like if anything, my prongs were never making contact. But it did make me wonder if maybe I do have it backwards and maybe that might be the issue.

 

That's really my last resort, though; if it's not that, then I gotta replace this motor because I don't know what else to test or fix.

Link to comment
Share on other sites

8 hours ago, spacecadet said:

I did test that the other day; I took the System Utilities disk from my Floppy Emu and used it to copy itself to a blank disk on the internal drive. Writing and then reading the disk back worked fine. Actually every time I do anything with the eject motor now I've been testing with that disk afterwards just to make sure the drive still works and I didn't mess up anything else. It's a fully functional drive other than ejecting.

 

Today I tested continuity of the wires to the motor itself and they *seemed* fine, although maybe you can verify for me how they're supposed to be connected, because I was getting cross continuity between red and brown wires in addition to each wire individually. Is that right? I looked at the soldering and I didn't see anywhere it seemed to be touching by mistake. It seems like a really simple straight soldering job so I don't even know how to fix that if it's not right, because I couldn't figure out why I was getting cross continuity.

 

As part of doing that, though, I also took the PCB off the motor just to look underneath and see if maybe there was solder there too (there's not; the wires just go straight through and are soldered only on top). And I saw how it seems like there are two metal posts with a set of "prongs" on one that act like a spring that's pushed out of the way by a cam on the motor gear when a disk is inserted. (That seems backwards but it looked like the only possible way it would go, unless my main gear is on backwards!) Is that the way this is supposed to work? One of those posts (the one with the prongs) seemed loose, although there was still continuity, but I re-soldered that so it's securely in place. Still no change in the motor behavior, though.

 

But it did make me wonder about that because it seems like that's a really obvious failure point from simple metal fatigue, and I wonder if mine is still just out of place a little. It's impossible to see how it's actually going in when you put it back together. But how is that supposed to look? Should those horizontal prongs be in contact whenever a disk is *not* inserted, and then get pushed apart when a disk is inserted? It seems like it's supposed to know to stop running when that circuit is made. If that's correct then I doubt it's my issue because it seems like if anything, my prongs were never making contact. But it did make me wonder if maybe I do have it backwards and maybe that might be the issue.

 

That's really my last resort, though; if it's not that, then I gotta replace this motor because I don't know what else to test or fix.

 

It's pretty simple to test if the motor is stuck. Remove it from the drive chassis, open the little trap door, gently hold it so that the gears are facing up. Power on the system, insert a disk, and press eject. Watch the drive gears to see if they move. 

 

Shoot a photos of the edge card on the motor and of the little Molex connector, and (on the photos; make them big and zoomed in!) mark the pins where you were getting cross-continuity. I will check that on known good and known bad drives here, and see if that indicates a short circuit condition in the motor itself. I do not remember that being normal, but it's possible that it is. 

 

Back in the 90s, we had stacks of these mechanisms, and we would tear them down, figure out which had bad analogue boards, which had back head motors, which had bad eject motors, which had bad heads; then catalogue all of the good parts and assemble refurb drives. I got to know them a bit more intimately than I probably wanted, but I have worked on restoring small electro-mechanical devices for decades; pretty much all sorts of diskette, cassette, reel, and platter drives. 

 

At my age, this is somewhat straining, but I still do it for m'self. 

Edited by GameGeezer
Link to comment
Share on other sites

I did as you suggested with the motor to test it directly, and got nothing. I thought I shot video of it but I guess I missed the button or something and it didn't record. But anyway, there was just no response from it doing the test exactly the way you suggested. I even turned the large gear 180 degrees so the cam would allow the circuit to close just in case I had something backwards and that didn't work either.

 

As for the cross continuity, attached are the photos you asked for showing the solder points I'm getting cross continuity on. I get both straight and cross continuity on these four, which are the red and brown wires. In any case, the motor just never turns on.

 

Edit: and I realized the first pic is cut off in such a way that you can't quite see the left side of the board and whether they might be connected by the large trace there. So I'm attaching another photo I took before that shows that. I had to resolder after that but I got the cross continuity both before and after resoldering, and my new solder (while not the best job) is not touching the other side.

 

IMG_1207.JPG

 

IMG_1208.JPG

 

 

P1060583.JPG

Edited by spacecadet
Link to comment
Share on other sites

Ok, so if I'm reading that right, then it seems like the continuity I'm getting is correct. That resistor is only 240 ohms so my meter's probably still beeping through it. I didn't look at the actual values I get between wires; next time I open it up I'll try doing that, but I don't know if it really matters that much at this point. It still just seems like a dead motor, and I'm actively looking for a donor drive now. Probably will post a WTB here as well.

Link to comment
Share on other sites

On 5/5/2020 at 8:35 PM, spacecadet said:

Ok, so if I'm reading that right, then it seems like the continuity I'm getting is correct. That resistor is only 240 ohms so my meter's probably still beeping through it. I didn't look at the actual values I get between wires; next time I open it up I'll try doing that, but I don't know if it really matters that much at this point. It still just seems like a dead motor, and I'm actively looking for a donor drive now. Probably will post a WTB here as well.

 

When I get a chance to test some of the eject motors that I have on hand, I'll let you know. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...