AppleCD 300 can't eject after inserting caddy

[wottle]

I'm trying to fix up my Macintosh TV and the CD ROM would not take a CD initially. I know the AppleCD 300 drives are notorious for their capacitor leakage, so I removed the drive, took the shield off, removed the board and could see a significant amount of damage from leaky caps. I cleaned up the board as best I could, took my console5 tantalum cap kit and swapped out the caps, and threw the drive back in the Mac TV and the drive seemed to be working really well. Disk would mount quickly, I copied some large files off it, all good.

Then I put the front bezel back on. This drive has a neat mechanism where the CD drive door changes when a drive is inserted. Looking at the mechanism, it seems like there are two doors (one that flips up, one that flips down. When the caddy is pushed in, the "drive is empty" door gets pushed down and a release is triggered so the "CADDY LOADED" door pops down from the top. It won't come all the way down over the door until the caddy is fully inserted, then pulled into the drive.

The problem I'm having after reassembly, is there CADDY LOADED door stays in front of the drive, even when I eject the caddy. So the drive is pushing the caddy out, but the CADDY LOADED door is still there, meaning the caddy can't eject.

Looking at the mechanism, there's a lever arm on the left side of the back of the CD 300 bezel that, if pushed down, will retract the CADDY LOADED door up and out of the way. I see inside the drive mechanism there's some sort of metal lever on the left side of the drive that seems like it would be responsible for pushing that lever to retract the door. The problem is that during manual or motorized eject, that lever in the drive never moves. I'm afraid to do too much disassembly with this drive without a good reassembly video because with all the springs and levers interconnecting, I'm not confident I'd be able to reassemble. I don't want to ruin the drive (which is now working, as long as I don't put a drive bezel on it).

I've refurbished floppy drives before (and on this Mac TV) but this mechanism seems more complex.

 

[retr01]

Hi @wottle!

Can you post a video of what is happening after you open it up and run it? Video of when it ejects would help to see where the problem is.

 

[lobust]

I know exactly the lever you are talking about because it's a right pain in the a**e to get the bezel back on with that lever engaged properly.

The tab on the door always wants to go to the wrong side of the lever when you're fitting the bezel, and then it doesn't work as you said.

Before assuming that something is wrong with the drive mechanism, make sure the tab is on the correct side of the lever - unfortunately I don't have mine easily to hand right now (I'm in a different part of the country for work rn) so I can't say for sure which side is correct. Assume that it's the one that is most difficult to get it to engage on when fitting the bezel...

 

[wottle]

Yeah, I meant to post a video with the original post, but got caught up in work things. Here’s a somewhat long video trying to explain the behavior.

The door mechanism itself:

And the eject where it doesn’t move the door out of the way:

 

[wottle]

Ok, so I figured out the problem. That arm inside the drive that I showed in my video was the problem. There was a torsion spring (couldn't think of the word for it in the video) that was supposed to keep the lever arm pushing down. It had fallen off it's mount point and so the lever arm that should have pushed down on the CADDY LOADED door lever was not doing so when the disk tray was raised for ejecting.

Here’s a video where I show the issue and how I was able to fix it.

CD300 eject door fix


While I show the fix, one thing not in the video worth noting for others if they have this problem, is that when you reattach the drive bezel to the front of the drive, in order to get the lever arm to work, you need the bezel to be re-set to have the CADDY LOADED door to be retracted and out of the way. This will allow the lever arm in the drive to correctly be positioned on top of the lever arm on the bezel. I didn't do that the first time and when it tried to eject it did not retract the door and the torsion spring came off the mount again. So, make sure things are in the proper order on reassembly and that the CADDY LOADED door is retracted up and out of the way.

 

[wottle]

Also, for documentation purposes for anyone else that needs to disassemble the drive to recap or fix the drive eject issue, here is how you take it apart.

First, remove from the front of the computer. There's a tab underneath that you lift up as you pull the drive out. It has edge connectors, so no need to disconnect any wires as you do so.

Once removed from the computer, remove the two screws holding the metal shield from the top of the drive.

With the shield removed, you can access two additional screws holding down the drives main controller board. Remove the two screws, but be careful with the board as there are 4 connectors you'll need to carefully disconnect.

Once you have the screws off, flip the board up from the right side (if oriented like my photos. There are 2 ribbon cables and 2 jst connectors that need dto be unplugged. The ribbon cables will require releasing the latch by prying up the plastic connectors around the outside of the ribbon. Once done, the ribbons will slide out. The JST connectors can simply be pulled loose.

With that, the board is free. If you've gone this far, definitely recap that board now that it is out. My drive was having issues reading disks, sometimes just ejecting as soon as one was inserted. When I pulled the board, the caps had been leaking badly and had done some significant corrosion to the surrounding areas. I replaced the caps with tantalums and its working great now.


Here's some pictures of the lever arm and where I had to reconnect the torsion spring to restore the ability for ejecting to move the CADDY LOADED door out of the way.

 

[retr01]

Hey @wottle, what is that "Tip Tinn" in a small tin case in the top right corner of the first picture? Thermal something to protect your fingertips from the hot computer parts after you just turned off, unplugged it, and opened it up quickly in mere seconds without cooling off?

 

[wottle]

Hey @wottle, what is that "Tip Tinn" in a small tin case in the top right corner of the first picture? Thermal something to protect your fingertips from the hot computer parts after you just turned off, unplugged it, and opened it up quickly in mere seconds without cooling off?

I may or may not have forgotten to turn off my soldering iron one day and then left for 5 hours. I thought it had an auto cut-off, but I was wrong. Tip was in pretty bad shape...

 

[retr01]

Ah! So, your CDROM drive in your Mac TV is fixed. High five!