Amiga 500 Casing - How to put on

[Rissy]

This is a weirdly titled topic, and i swear i'm not a moron, but tonight after finally playing about the gubbenry inside (or so i thought), I decided it was high time to make the computer look like an Amiga again. So i wanted to put the casing all back on. Once i put the whole kitten caboodle back together (shielding and everything), the Amiga then wouldn't read any floppy discs!?

After a good few hours testing permutations of leaving stuff off, putting screws in, not putting scews in etc. I finally found out what's causing it. Its the top plastic half of the casing. It seems to be pressing down on the floppy or something, which then means instead of reading discs, it just clicks a few times and gives up. Lift up the top half of the casing away from the floppy drive, and it works again.

What's the deal? Is it a precision operation of delicacy and accuracy just to put the lid back on this thing and have it still work or what!?

Is there a method of that adjustment screw on the side of the floppy drive? I have the floppy held with both stand offs and screws underneath, whereas when i first opened the thing up over a month ago, the rear most stand off was missing, and i had to find a replacment (which i did by buying a whole floppy drive from someone on Ebay!) I wonder if this is why that standoff was missing now....

[Jope]

Sounds like you are forcing your floppy drive to bend a bit when you're installing it. If you have the correct size standoffs in three corners (or only the rear if it's a thick drive), the drive will just sit in the correct position and then you can tighten the horizontal screw that points to the front of the machine.

There are two different thicknesses of Amiga 500 floppy drive, make sure you have the correct hardware setup for your particular drive.

[Rissy]

Thanks for your reply. I'll have to measure the thickness of my drive tonight. I had no idea there was more than one thickness. It's a model FB-354 that has been in there since factory build (My original floppy drive). The drive looks horizontal when sitting there on two stand offs and the third "adjustment" screw. But i'll give it a closer inspection tonight.

[Rissy]

Weirdly enough, i tried replicating the fault without the casing. I tried pressing down on all sorts, including the floppy drive. I couldn't make it fail no matter what i did. But as soon as the cover goes on. That's it. Such as simple thing one wishes to do!

[Jope]

Can you take pics without the cover to see how the drive + keyboard sit?

[Rissy]

Originally Posted by Jope

Can you take pics without the cover to see how the drive + keyboard sit?

I could do yeah. Not until tonight after work however. Although, if you look at my resurrection thread, i'm sure i've got photos and even videos on there which may show you. You may have to pause of course.

[Jope]

The memory expansion pic shows the drive. It looks fine in that pic. If it's level in comparison to the rear of the case, you should be fine. No short circuits from the shielding under it?

[Rissy]

Originally Posted by Jope

The memory expansion pic shows the drive. It looks fine in that pic. If it's level in comparison to the rear of the case, you should be fine. No short circuits from the shielding under it?

I don't think so. I've "hooked" the top shield OVER the vertical components from the lower shield part, and the legs of the upper shield are screwed to the motherboard pads as designed. I suppose i could remove the upper shield again and try the case on again to see if it still does it.

I may have to resort to another YouTube video!

[Jope]

Yeah, by all means try it without the top shield. Obviously something is moving and pushing at the wrong place if it doesn't work with the lid on.

[Rissy]

I found my problem!! OMG. It took me ages. So obvious once you see it.

There is clearly a difference between my original floppy drive, and another i bought off Ebay about a month ago (before i managed to get my original one working again after long term storage).

Originally I thought it was down to the eject buttons being different. My original floppy drive button has some sort of shoulder on it that the Ebay one doesn't have. But that turned out to be ok, and wasn't my problem.

My problem came from a different design of bracket that the eject buttons is mounted to. My original has a full width bracket which the Ebay one doesn't. When i was applying the top half of the case, the inside of this was pushing on this full width bracket, and attempting to partially eject the disk in the machine, and this was causing the drive to click repeatedly for about 3 read attempts before it would give up.

My solution was simple, if not a little brute force-ish. I bent the bracket back with some wide pliers a bit. This has given the clearance away from the inside of the upper case i needed so that there was no contact with the bracket any longer. Now all my disks load as normal in the same way as they did with the Amiga still in pieces, except now, it's fully built and looks like an Amiga again.

Enjoy my photos.

[Jope]

Ah, your replacement drive has internals that were intended for a big box Amiga. They have that long bracket for the eject button.

I must say I wouldn't have guessed this one.

[Rissy]

Originally Posted by Jope

Ah, your replacement drive has internals that were intended for a big box Amiga. They have that long bracket for the eject button.

I must say I wouldn't have guessed this one.

Ah but you don't understand. The drive with the long bracket is my original drive which has ALWAYS been in my Amiga 500 from new!

The one without is an arbitrary Ebay purchase last month.

[Jope]

Well that sounds very strange indeed then. :-)

Did you check the standoffs at the back of the drive? Are they all the same length? As said, the drive should sit level on three corners when installed in the machine with no screws if you have the correct standoffs.

[Rissy]

Originally Posted by Jope

Well that sounds very strange indeed then. :-)

Did you check the standoffs at the back of the drive? Are they all the same length? As said, the drive should sit level on three corners when installed in the machine with no screws if you have the correct standoffs.

Yes of course. I took the drive out and checked everything (except the awareness of th bracket difference at the time of course). I tried having things not on, then on again, things screwed in, then not screwed in. I went through so many permutations of differences until i got to the point where everything was on except the top case, then i slowly lowered the drive side of the top casing down first to clip it into position.

When i did this, i started noticing ever so slight movement of the drive eject button. (by this time i was on to this test WITH a disk in the drive, as i had already tried it without a disk in the drive, and course, this showed nothing as the bracket at fault was fully retracted inside the drive. When there is a disk in, the bracket protrudes out towards the inside of the casing, and the top half clicks inside the bottom half, so it's narrower. The bracket never touches the bottom half of the case, only the top half.)
It was the movement of the eject button which was the give away to the fault eventually. I thought it was the button itself initially, but then i tried a test of lying the top half of the casing on the floor upside down, and held the drive with my hand, upside down, roughly in the correct position and then proceeded to eject the disk and push the disk in, watching everything that moves around the side of the casnig. Quickly i decided it was not the button from that test, and then suspected the bracket. At that point, i compared my original drive with the Ebay one and saw that the Ebay one didn't have this bracket at all! I then put the drive back into the bottom half, screwed it into place, and started the top half lowering down experiment again, this time carefully watching the bracket the best i could. Het presto! I found the culprit!
...and the rest is history.

I've never even tried the Ebay drive yet, as it needs cleaning. I wanted a drive in case i couldn't get my own working, but also, the Ebay one came with two standoffs, and i was missing a standoff. But after this little episode, the Ebay drive has definitely paid for itself, as without it, i may never have suspected the bracket at all. I had no idea at all that my drive was designed for a completely different Amiga than an A500! Maybe they ran out of A500 floppy drives when my Amiga was being built in the factory!? Who knows. History can be interesting.

[Jope]

The drive with a wider eject button plate is compatible with the A500/A3000. I'm still very puzzled as to why yours is hitting the edge of the case. I guess I need to try one of my A3000 drives in an A500 to see what is happening here.

.. moments later.

I went to my work room and found an A500 with a chinon drive. Took photos of it. Then I found a spare A3000 drive, swapped the mounting hardware + eject button from the A500 chinon to the A3000 chinon and installed it in the A500 case.

Absolutely no interference, top case fits in fine.

I have no idea what is going on with your setup.

Here's some pictures I took while I was at it.
http://jope.fi/amiga/a500chinon/

[Rissy]

Originally Posted by Jope

The drive with a wider eject button plate is compatible with the A500/A3000. I'm still very puzzled as to why yours is hitting the edge of the case. I guess I need to try one of my A3000 drives in an A500 to see what is happening here.

.. moments later.

I went to my work room and found an A500 with a chinon drive. Took photos of it. Then I found a spare A3000 drive, swapped the mounting hardware + eject button from the A500 chinon to the A3000 chinon and installed it in the A500 case.

Absolutely no interference, top case fits in fine.

I have no idea what is going on with your setup.

Here's some pictures I took while I was at it.
http://jope.fi/amiga/a500chinon/

Even your A3000 drive has a different Eject button than mine. Mine also doesn't have that green LED yours does!?

It's fixed now, but it did mean bending that bracket back with pliers as shown in my photos! That drive has been in my A500 from new. I've owned this thing since i was a little boy and my dad bought it as part of the "class of the 90's" pack.

Both my Ebay and original drive has "FB-354" model label stuck to them. My original drive is a RevB with a serial number beginning with "1" and my Ebay drive doesn't have a Rev number, but its serial number begins with "2".

[Jope]

Ok, now I understand what I'm seeing in your first eject button picture. Looks like someone has glued the button off a different drive into your original mechanism. The one in my pictures is the one that is supposed to go on this type of drive.

Are you sure the machine was never out for repairs back then?

[Rissy]

Here's a drive being sold on Ebay. It's also a Rev B, but it doesn't have the bracket!

https://www.ebay.co.uk/itm/333917298...AAAOSwcKtgShvK

Stranger and stranger!

[Rissy]

Originally Posted by Jope

Ok, now I understand what I'm seeing in your first eject button picture. Looks like someone has glued the button off a different drive into your original mechanism. The one in my pictures is the one that is supposed to go on this type of drive.

Are you sure the machine was never out for repairs back then?

I think it did go out for repair once, yes. For what reason, i have no idea. I guess the repair people are the ones who never put both standoffs back in.

[Rissy]

Here's a Rev E, with a "1" serial number. Again. No bracket and correct eject button.

https://www.ebay.co.uk/itm/224275847...cAAOSwGIxfCckN