Help With Ide and External CD-rom

[Havie]

So currently my Cd drive is in an external case and wired to my 1200 directly via an Ide cable that runs from the cd-rom to the buffered ide interface (through the removed modulator hole). All works well.

My problem is the Amiga is a bit unwieldy to move as the cd and 1200 are permanently attached. So my idea was to get a male to male 40 pin connector and run an additional ide cable from the cd-rom which I could connect to the ide cable coming from the Amiga thus allowing the two units to be detached for moving.

Connect fits ok and I had one ide cable with 3 connectors that I could use. It was too long so I cut it short below the middle connector, leaving a shorter cable with just the middle and one end. But when I connect it up to the Amiga cable the cd-rom light comes on and it just does nothing. If I swap the cable round then the cd-rom works ok but the Amiga doesn't see it (it obviously doesn't see it the other way round either).

For now I have put it back how it was and it works fine.

So my question is - was cutting the cable not the right thing to do as in theory all I have done is create a pass-through and a slightly longer cable or could there be something else at play?

The cable is still reasonably short and certainly no longer than a foot. Also, even if the Amiga is not powered up I have teh saem problem with the cd-rom when I connect the too cables - maybe there is some sort of short on pin 1?

Anyway, thanks for any ideas you might have.

[thomas]

Originally Posted by Havie

male to male 40 pin connector

Can you make a photo of this?

I must be a special connector which connects the upper row of one side to the lower row of the other side and vice versa. A connector which just passes through 1:1 will not connect the right pins of the two cables.

[Havie]

I never realised this - that would explain it. This is the connector:

http://eab.abime.net/showpost.php?p=...postcount=6260

So is it possible to buy what I want or is there another way of doing this? It would just be nice to be able to plug the cd-rom in and out for moving.

[Havie]

Originally Posted by thomas

Can you make a photo of this?

I must be a special connector which connects the upper row of one side to the lower row of the other side and vice versa. A connector which just passes through 1:1 will not connect the right pins of the two cables.

Also, can you explain why? Is it because I used the middle connector?

[thomas]

Originally Posted by Havie

Also, can you explain why?

It is geometry.

If you look at the connectors when they are next to each other they are numbered like this:

1 3 5 7 ... 39 | 1 3 5 7 ... 39
2 4 6 8 ... 40 | 2 4 6 8 ... 40


Now if you turn one around and connect the nearest pins you get

1 -> 39
2 -> 40
3 -> 38
...
39 -> 1
40 -> 2

But you have to connect 1 to 1, 2 to 2 and so on. That's why the adapter must take this into account.

[thomas]

You need an adapter like this one:
https://www.delock.de/produkte/G_650...setLanguage=en

[thomas]

Or like this:

https://www.ebay.co.uk/itm/3-5-IDE-P...IAAOSwFGNcIFWo

[Havie]

Originally Posted by thomas

It is geometry.

If you look at the connectors when they are next to each other they are numbered like this:

1 3 5 7 ... 39 | 1 3 5 7 ... 39
2 4 6 8 ... 40 | 2 4 6 8 ... 40


Now if you turn one around and connect the nearest pins you get

1 -> 39
2 -> 40
3 -> 38
...
39 -> 1
40 -> 2

But you have to connect 1 to 1, 2 to 2 and so on. That's why the adapter must take this into account.

Of course, now you say that it's completely obvious - doh!

I like the second adaptor better as it's a but more like a port you'd plug into. I wonder if you can get one back to back as I might be able to mount it on the back of the cd-rom case (it was a SCSI case).

Thanks!

[thomas]

This one maybe:
https://www.amazon.co.uk/dp/B00HU8OXOO/

[Havie]

Perfect and ordered. Thanks.

Will let you know how it works.

[Havie]

Thanks Thomas - arrived today.

http://eab.abime.net/showpost.php?p=...postcount=6281

I will post finished (and hopefully working) project when I find time to do it.

[Havie]

It works!

Have my cut of cable attached to Cd-rom which comes out one of 'holes' (SCSI sockets -removed) at he back connected via interface to the ide lead coming out of the 1200 through the removed modulator socket.

I now have a detachable cd-rom. The neatest solution would be to mount the adaptor on the back of the 1200 like another port but I don't want to damage the Amiga to do it so will leave it like it is. I could use the clockport space (I think - haven't checked) so this is the next stage (possibly)?