Fixing the floppy drive of a Macintosh SE without dying

[victor.muc]

Hey everyone,

I’ve repaired a lot of Apple hardware over the years (PowerBooks, iBooks, iMacs, Intel Macs, etc.). Over the last couple of months I’ve been doing at least one repair per week, even if it’s just something minor, so I’m usually not afraid of taking things apart.

That said, I’ve now run into my personal CRT fear.

I recently picked up a Macintosh SE with a failing floppy drive. The drive initially worked: it accepted a disk and I was able to eject it twice. On the third eject attempt however the disk got stuck while the eject motor kept spinning continuously. I had to use a paperclip to remove the disk, and since then the eject mechanism seems to run nonstop.

I’d like to open the SE and remove the floppy drive so I can clean and repair the mechanism (my replacement gears arrived today). However, the CRT and high voltage area make me a bit nervous. I’ve watched several teardown videos and I know where the dangerous parts are (flyback, anode cap, rear of the CRT, analog board), but I want to be 100% sure before proceeding.

Is it safe to open the SE and remove only the floppy drive if I stay on the left side and avoid touching the CRT, flyback, and analog board entirely?

I do not plan to go anywhere near the CRT or the analog board.

As far as I understand, discharging the CRT shouldn’t be necessary unless I actually need to work near it. The SE has been unplugged for about two months, so unless the bleeder resistor has failed, it should already be discharged. I’m also hesitant to discharge the CRT myself, so I’d appreciate confirmation on whether this is sufficient.

Is this approach completely safe, or is there anything specific I should still be careful about?

Any advice or reassurance from people who have done this before would be greatly appreciated.

Thanks in advance!

 

[bibilit]

Yes no issue if you only remove the drive.

 

[Boctor]

The discharge with the alligator clip and flathead is pretty safe and straightforward, if you don't trust the bleed resistor. You don't have to put your actual hand anywhere near the conductor, just the screwdriver and alligator clip sending current straight into the ground lug, assuming it's even there. The drive cage should be nowhere near the actual transformer.

Do you have a second Mac, preferably a pizza box or just one that's easy to open, for testing the drive while working on it? I've had to fix the zero-track alignment before, which you hopefully won't have to if this is just cleaning/lubing, and that took a lot of trial and error.

 

[cheesestraws]

Yup, as @bibilit says, you'll be fine to work on the low voltage stuff, including the drives. I appreciate your caution.

 

[joshc]

Discharging without knowing what you're doing is going to expose you to more risk than leaving it alone and only dealing with the drive without touching the CRT at all. There used to be a lot of advice around always discharging the CRT no matter what you were doing in the machine, over time that changed to people generally saying to leave it alone if you're not going to be dealing with the analog board/CRT. It's really good to be mindful of it though.

 

[ClassicGuyPhilly]

Breaking open a Compact is a right of passage! Good luck you'll be fine

Here are my notes and pictures on the floppy drive maintenance if you're unfamiliar

Post in thread 'Rescued what I thought was a Mac II' https://68kmla.org/bb/threads/rescued-what-i-thought-was-a-mac-ii.44257/post-489303

 

[victor.muc]

Thank you all so much for the kind and valuable comments!

I actually did overcome my CRT fear today and finally fixed the floppy successfully (without getting shocked)!!

The floppy drive itself and more importantly the eject mechanism work, but it’s still a bit weird. It won’t insert the floppy by itself, so I have to manually put it all the way into the hole myself.
Ejecting also only works a few millimeters, and after I eject a disc, it recognizes an empty „ghost“ floppy.

I disassembled the whole drive and cleaned and lubricated it, so I think I forgot something on assembly. I’m not even sure if I put the 2 springs back in since I removed them a couple of times .

@Boctor was right, a test device would be a good idea in this case, but unfortunately, I only got 2 desktop vintage Macs (the SE and an iMac G3), the rest are way too many PowerBooks. 

I will disassemble the whole thing again tomorrow and fix things up. Also a tip for anyone who opens this thing for the first time: the thick power cable which goes from the Analog board to the logic board has a clip on the bottom side. I took 30 minutes trying to disconnect it until I saw the clip. That was my dumbest mistake I ever did with a vintage repair. 

 

[victor.muc]

I can’t remove this comment, just ignore it

 

[victor.muc]

I’ll add some pictures as well, maybe they’ll help someone else someday as reference.

I forgot to take photos after the final cleaning and lubrication since it got pretty late, but at least I have some in progress shots to show the disassembly and general layout.

 

[iantm]

FWIW I came into all this Mac resurrection just a few months ago knowing little to nothing, got super afraid of offing myself with voltage but took all the precautions I could, following the alligator clip disharge every single time I unplug. And now I work back there like I'm cleaning a fish tank, done it dozens of time, no shocks.

I did snap one yoke connector though, heard the paralyzing "hiss". I highly recommend protecting that with one of these caps.

The floppy drives still intimidate me. I will probably get to that once I'm satisfied the rest of the machine is set up, I want to use it for daily writing… Let us know goes, I hope it goes smoothly for you, maybe that will give me hope I should try!

 

[Snial]

<snip>, the CRT and high voltage area make me a bit nervous. I’ve watched several teardown videos and I know where the dangerous parts are (flyback, anode cap, rear of the CRT, analog board), but I want to be 100% sure before proceeding.<snip>

I've had to take apart my Mac Plus and SE from time to time. I'm not particularly clumsy as such (I've recently replaced an iPhone SE 2020 screen and battery, then an iPhone XR screen), but I lack some degree of multiple spatial awareness so I could quite easily touch a CRT while removing some other component. And compact Macs, although simple are still fairly tricky and awkward (My Plus has a tall bank of SIMMs that touch the underside of the chassis, so as I'm carefully sliding the logic board past all the snags I need to bend it slightly (<1mm in the middle) to get the SIMM through).

My technique is, I normally unplug, then wait 1 day after I've tested it before opening it to allow ample time for discharge.

 

[Boctor]

Looks like your auto-eject gear blew up within mere days of mine doing the same. Always with that funky green spot, too... It sure was thoughtful of those plastics to hold off on breaking down until 3D printing became widespread.

 

[luRaichu]

Always with that funky green spot, too...

It's made of moldy cheese