How did I break my 1581 and FIVE floppy drives?!

Let’s convert a Samsung SFD-321B PC drive for use with the Commodore Amiga & 1581 to try and fix my mistake.
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00:00 Introduction
01:14 1581 Replicas are failing mysteriously
03:04 A stack of dead PC drives: I messed up!
06:00 The Samsung SFD-321B disk drive
07:07 Differences between PC and Amiga/1581 floppy drives
07:59 Converting the drive: Drive Select
09:14 Converting the drive: Disk Change to Ready
11:49 Converting the drive: Density to Disk Change
13:48 In Use / NHDD Jumper
14:07 Capacitors, head cleaning, lubrication, and LED removal
16:55 Testing in the Amiga 1200
18:52 Testing in the 1581 replica
21:02 Samsung fitment issues and 3d printed brackets
21:50 Consider this before buying a replica board!
22:43 Conclusion

[@retrobitstv]

Correction: When I stated that the ribbon cable connector on the adapter board was backwards, that was incorrect. As it turns out, upon removing the connector, the FDD interface pins are mirrored on the output of the adapter so I had it correctly fitted. Only the mini molex power connector was backward.

[@dennisp.2147]

Your next video needs to be "Repairing 5 floppy drives"

[@retrobitstv]

Hah, I'll consider it!

[@joysticksnjukeboxes]

Kudos for not losing it and smashing everything in a fit of apoplectic rage like I would!

[@jandjrandr]

I have to agree. Thank you for being patient! I ran into similar fails myself when trying to install a ZIF socket in place of the SID socket on my recently fixed C64 and somehow the board now doesn't work. You've encouraged me that it is time to break out the troubleshooting tools for me.

[@coffeecuparcade]

I love how you recovered from the 5 down. You learned, we all learned, and we get another awesome video. Win? In the end you got your awesome Amiga drive back in action. Great job!

[@minombredepila1580]

Please do not feel stupid. We all have made mistakes (and will in the future). Loved this video and I happen to have the very same FDD that will convert to my amigas as a 1581 !!! Thanks for the video.

[@00Skyfox]

My worst retro screwup? Off the top of my head (and there were probably a few worse ones) was when I had a pristine C64 case that looked brand new sitting in a spot I thought would be safe, but then knocked something over onto it and broke off a huge chunk from the bottom half of the case. Loctite plastic weld fixed it but the crack is still visible. I screamed.

[@CRG]

Fantastic video and thanks for the shout out. Great to see the 1200 is getting put to some good use. That replica 1581 looks like a nice project I'll have to check out Tim's videos on it too.

[@Renville80]

On the subject of screw-ups, I had an industrial motor control in for a routine rebuild (it was a weak, failure-prone design), and I thought I'd found and renewed all the failed components, including the 10 ohm, 50-watt brake resistor. I set up for the 'light test' to make sure everything was good before installing it into the process controller, and about 5 seconds after I turned on the power, a flame a foot tall shot out of the unit! Every single component I'd just replaced had already failed. While stripping down the board for another rebuild, I realized I'd forgotten a 1N4005 sandwiched between two big capacitors...! I had to wait a few days for parts as I'd used the last brake resistor on the shelf. When it was time to do the light test again (and on all the others that came across my bench for the next six months), I had one of the other people in my department do the light test for me.

[@retrobitstv]

Haha that's way more exciting than my little drive escapade. Nice one!

[@TLang-el6sk]

I bought 2 of these drive for my replica. It turned out that also the switches for disk and HD detection can go bad. Furthermore there are several revisions of the SFD-321B, I had one where the switch for HD detection was missing from factory. I believe to remember that I checked the configuration and that drive was hardwired to HD from factory.

[@Otakunopodcast]

Back when I first started building PCs, I was young, stupid and reckless, and without thinking or even doing basic research, I hooked the power supply up wrong. This was back in the days of AT (not ATX) power supplies, which had two connectors that sort of look like oversized berg connectors that plugged into the motherboard. They were individually keyed, so you couldn't put them in backwards. But you could get the order of the two separate connectors swapped around. Which is exactly what I did. And when I hit the power switch, there was a thunderous BANG accompanied by a bright flash of light and the magic smoke got let out. Scared the crap out of me, I must have jumped nearly 10 feet. Of course both the motherboard AND the power supply were toast and had to be replaced. Would have been bad enough if it were my own PC, but it wasn't, it was a machine I was building for my girlfriend. Oops. Being the kind soul that she was (she is sadly no longer with us today) she forgave me, but I got teased about it for the longest time. Also during that same build, I nearly put my eye out. I was trying to screw in a particularly stubborn screw, my screwdriver slipped, the screw went flying, and landed right in the middle of my left eye, with a surprising amount of force. Fortunately luck was on my side, there no permanent damage, only a corneal scratch, which healed in a few days, but it sure hurt like a mother. From that day forward I now wear safety glasses whenever I do any work on electronics things, no matter how small or simple or quick the job might seem, I prefer to play it safe.

[@retrobitstv]

Ah yes I remember those days. Oops, that was an expensive mistake! Well at least you knew right away what went wrong I guess :P It's been a looong time but if I recall, the matching colors (black?) from each of the two plugs needed to be next to each other?

[@robertsissco2439]

Don't feel bad, I got a 1581 clone PCB from DIYChris and I did the exact same thing. I needed to order a new 3.5" drive to go in it, luckily I made sure to learn from my mistakes

[@retrobitstv]

D'oh! Ah well, misery loves company :)

[@Commodore128Mode3]

Amazing: I just re-watched the episode where you made the replica 1581 just 3 days ago.

[@retrobitstv]

Perfect timing!

[@CantankerousDave]

I’ve just started learning how to solder to replace bad caps. Experienced people make it look so dang easy.

[@retrobitstv]

For what it's worth, I had no real soldering skills when I started doing retro stuff 4 years ago (and still have a lot to learn). Practice and all that :)

[@panopolis8051]

Tutorials always help, but as with most skills there's no substitute for practice and experience. Some tips: using good quality soldering iron, solder, flux and desoldering braid helps a lot. Adjust the temperature as needed, too much heat can damage pads/traces/components, but with too little heat the solder won't flow well. Use the right soldering tip for the job, the shape and size depends on what you are soldering. Good luck!

[@terosaarela4555]

Glad to hear you got your 1581 working again! Hopefully Tim and the others get their’s sorted out too. I was lucky enough to score one 1581 kit with eclosure and original logic board back in the day. I had to sacrifice one Amiga 500 for the Chinon drive mech (okay, the Amiga was in pretty rough shape overall). I’ve fudged a RAM upgrade on a CoCo2 by soldering the jumper wires wrong. Spent a fair time and money sorting that out.😅

[@75slaine]

Phew, glad that's sorted. Thanks for sharing this video, I still intend to build one of these so this is valuable info.

[@michaelcarey]

Ahh yes, you have to be careful with connectors. The other thing that is different with the "Berg" floppy drive connector is that the pin spacing is 2.5mm and not the more common 2.54mm (0.1"). I found this out when I designed a replica SX-64 I/O PCB which use 2.5mm connectors. I had to make sure I used 2.5mm Molex KK connectors as the right angle version of these have the locking tab located close to the PCB, the 2.54mm KK connectors have the locking tab located away from the PCB. You can jam a 2.54mm connector onto a 2.5mm socket... but you will flip the pins. It looks like the connector you fitted to the interface PCB was the wrong kind.

[@retrobitstv]

Good to know, thanks! Yea it looks like I ordered the wrong part. Since it comes pre-angled from the factory, the only way to install it on the top side of the board is the wrong way unless I want to bend all the pins 180 degrees. Now that you mention it, the locking tab doesn't latch very well, another sign I messed up :/

[@whochecksthis]

Brings me back to 1987… I ran geos 128 for my dad’s business…

[@LeftoverBeefcake]

I don't remember the make of the PC floppy I modified for use in my Amiga, but it sure was a heck of a lot more difficult to change around than the drive in your video, mainly because the SMD resistors that needed to be moved were way smaller. In the end I got it done but boy was it a pain. :( I once fried a friend's CD-ROM drive because I accidentally plugged the audio output into the wrong pin header on the main board. Thankfully I'm a tech packrat and had a spare drive. D'oh!

[@retrobitstv]

Whoops! Good ol' un-keyed, un-labelled motherboard pin headers! Glen at CRG just shared a tip with me about removing those SMD resistors - he said heat them from the side and they'll pop right off and stick to your soldering iron. Adding a little fresh solder to the iron may help it along. I haven't tried it out yet but it sounds a lot easier than all the messing around I went through ;)

[@JamiesHackShack]

Way to go on the fix! @retrocombs and I picked up some shucked cases/faceplates at world of commodore back in dec. Makes me want to maybe do one of these builds. I was wondering about that eject button but I guess there's already an stl out there for it and some other internal mount needs. Thanks!

[@retrobitstv]

Nice, I wasn't sure that the seller still had any for sale. He went radio silent after the reproduction boards starting coming out. There are lots of 3D models out there for different drives but due to slight variations they all seem to need a little tweaking :P

[@granitepenguin]

If the worst thing you did was toast a handful of relatively cheap floppies, you are doing ok. 🙂

[@chippey69696969]

what a great video - thank you so much!!

[@Renville80]

When I have to remove a chip component, I end up 'flooding' both joints with solder until the part floats off the pads. If the part is a zero-ohm jumper, you could just as well bridge the pads with a single strand of wire.

[@retrobitstv]

Cool, thanks for sharing!

[@16bitgium]

Such an awesome channel. Thanks for your content

[@retrobitstv]

Glad you enjoy it!

[@igork3522]

Good job! Thx for the video.

[@Numfuddle]

I can relate past me has caused lots of problems for present day me. I should probably have a serious talk with that guy some day.

[@8BitRetroReFix]

Awesome work ... I need to revisit my 2 boards 😉

[@GilbertoFerreira]

Let me ask something: RetroBytes and Retrobits are the same guy, isn't???

[@Numfuddle]

As for screw ups. I once blew up a customer prototype PCB because I connected it to 12v (automotive battery voltage) not realising that it was an add on board for a main PCB and only supposed to be powered with 5v. The bang could be heard through the whole office.

[@retrobitstv]

Ouch! Well, at least it was an impressive failure :)

[@preferredimage]

Ballsy move hooking a drive up to a whole amiga to test it after all the drama that came before it! Glad it all worked out. I think on your adaptor (assuming its not in a bin on fire already) you should be able to pull the plastic surround for both the power connector and even the floppy connector, flip them over and slot them back onto the pins, saving the desoldering.

[@retrobitstv]

Ahh good idea, I wish I had thought of that at the time. I ended up spending an hour or so to desolder everything with hot air and made a bit of a mess of it but got it done in the end. Once I removed the data connector I found that I had installed it the right way after all and the PCB itself flips the pins around, d'oh!

[@deborahberi3249]

I have a large batch of 3 1/2 in disk drives so I guess I probably shouldn't sell off any of them just in case I torch some in my 1581 builds lol! Mark.

[@retrobitstv]

Better safe than sorry!

[@Numfuddle]

I’m quite surprised that the drives worked at all with 12v going to the 5v rail. Usually something just blows up with a loud noise and the magic smoke is let out.

[@retrobitstv]

Surprisingly no bang or visible smoke, but one or two drives may have 'smelled a bit hot'. Of course these were either untested or hadn't been used in 20 years so at the time I just assumed the drive I was currently testing simply was bad. If only I had realized I had the power rails backwards sooner...

[@networkg]

I hope off camera you tested the new capacitors, would not want to replace bad with worse ! (been there, seen it, done it.)

[@retrobitstv]

I had previously tested a few from the lot to ensure they were generally within spec but I didn't test each individual part.

[@panopolis8051]

Those kind of mistakes hurt the most, but you know what they say, 6th time is the charm! Or something like that :P At least you won't be making that mistake again (hopefully). Also, maybe its fine, but it looked like some bare wire was exposed on the floppy power cable.

[@retrobitstv]

Haha yea, I would have been happy with the third time being the charm though :P Yea, my crimps are a little sloppy - I need a better tool. I did make sure they weren't in danger of shorting though!

[@panopolis8051]

@@retrobitstv I assumed you probably noticed it, but felt I should mention it just in case. Thanks for making these videos, they're always informative and entertaining

[@tommyovesen]

Great work. I've started building one of these replicas, so this was good. Many "gotchas" there I need to mind.

[@retrobitstv]

Cool, good luck with your build! If you haven't seen it already, my original build video is here and contains a few more lessons I learned along the way :) kzbin.info/www/bejne/bpCWq3-sjKhgkKs

[@tommyovesen]

Thanks! I purposely did not want to see many videos before I build it. Don't want to copy others :) I'll take a look@@retrobitstv

[@kokodin5895]

don't desolder plastic bits can be pulled off and put on the other way. it would be faster and simpler just a flat screwdriver and a bit of force, works for power connector too

[@retrobitstv]

Good idea! I already had a go at it with the hot air and eventually got it off but this would have been easier!

[@j0eCommodore]

Can you fix the five drives? That might be a useful video.

[@retrobitstv]

I spent an hour or so looking at the drive schematic for my original Samsung unit and trying to figure out what might have been affected by the over-voltage. I didn't find anything obviously burnt up though. It might be the controller IC itself; I'll have to look and see if replacements are even available. I haven't looked at the other 4 drives yet but it would be nice to fix them!

[@j0eCommodore]

I think it would be a good video a lot of repair ones don't go into over/cross voltage issues and it would be nice to see the implications and repaiability when such happens.@@retrobitstv

[@3dtexan890]

I am having a very hard time to find where to purchase the parts, except the floppy drive. Do you have any suggestions?

[@ddzh9291]

If I take an IBM PC HD floppy drive and do the same manipulations with it, will it work on AMIGA 1200 and will it allow to use HD floppy disks?

[@retrobitstv]

I do not believe so, unless the drive is a specific model of Chinon (FZ-3547A) that is designed to spin at a slower speed than a normal PC high density drive in order to keep the data rate to a speed the Amiga's interface can handle. I'm not saying it's impossible to do, but would require more than the changes I've demonstrated in this video.

[@megatech1966]

Can have a link to the board which works please.

[@retrobitstv]

Here is the original thread by the designer of the board. I used google translate and had to create an account on the forum in order to download any of the files: www.forum64.de/index.php?thread/102472-1581replica-gotek1581-1581-pc-drive-adapter/ Here's the thread on AmiBay where they used to be offered for sale but I do not believe this is active anymore: www.amibay.com/threads/commodore-1581-drive-kit-mainboard-with-improvements.122034/

[@peteruttman7504]

Can the damaged floppy drives be repaired?

[@retrobitstv]

I did check to see if any of the discrete components looked burnt on the original Samsung unit but didn't find anything. I'm sure it can be repaired with enough time spent testing components but if one of the custom ICs is shot it might not be possible to get a replacement. I have yet to look at the other 4 drives though...

[@stevensexton5801]

Glen can send me an Amiga 1200

[@ivorjawa]

Dude, get a more precise soldering tip!