Amiga 4000T floppy cable. Should it have twisted wires or not?

[StompinSteve]

Hello,

Small question: my Amiga 3000D has a dual-floppy ribbon cable and between both actual floppy-connectors (close to the last floppy-connector) some wires are twisted (wires 4 5 and 6 are swapped or something, if I remember correctly).

Anyway, while cleaning up my filthy, dusty, barn-find Escom/Amiga Technologies A4000 Tower, I noticed that the blue dual-floppy ribbon-cable doesn’t have any twisted wires.
The question: Is this correct? Or should the cable be like the one in the A3000D with the twisted wires at the end?

The reason I ask is because I have a gotek on the first connector (from the perspective of the disk-module) and the gotek has the "S0" jumper set. The second and last floppy connector goes into the DD floppy drive that came with the system. The unit is a Chinon FZ-357 and the shorted jumpers on it are "DS1 , MM, RDY and TTL/C-MCS". All other jumpers are open.
Jumper J250 is shorted (ON) which means "Second internal floppy (DF1) is Double Density (880K)
Where "OFF" means no second internal floppy, or second floppy (DF1) is High Density 1.76MB

Both GOTEK and the Chinon work great. Everything works fine but...

But when the GOTEK is working, the activity-led on the Chinon also lights up as. There is no floppy in it and it makes no sounds, it's just it's LED that is active. Kinda wierd and the reason for me to start having a look at the cable.
I don't know how the floppy ribbon cable is supposed to be connected. Should the middle connector on the cable be connected to DF0 and the connector at the end to DF1 or the other way around? Maybe it's done wrong which is why the LED on the Chinon burns when the GOTEK is performing I/O ?

[Jope]

The missing twist causes the floppy LED problems you see.

[StompinSteve]

My 4000T was also delivered with a loose Micronik Power M-Disk 1.76HD floppydrive. Cleaned and greased it today, then hooked it up (jumpered as DF1) instead of the DD drive. Removed the jumper from J250 ("OFF" means no second internal floppy, or second floppy (DF1) is High Density 1.76MB") and now the LED on the floppydrive behaves differently. This drive's LED does NOT light up when there is activity on the GOTEK????
If I then put a DD floppy in it, it works perfectly. Recognised as DD and all tests good.
But if I put a HD floppy in it, AmigaTestKit recognises it as HD and all looks fine. The Signal Test is good. But then, when I run a "read test" on the HD floppy, I get a red "M" sign on every track, it's super slow to read the tracks and it says "No READY signal: PC or Escom drive?".

When I boot Workbench 3.1.4.1 I can format the HD floppy but it's struggling. Writing a 1.6 MB file to it is also a struggle and during the verify-after-copy, I get read errors. I tried several HD floppies.
At the same time, this HD drive has no issues with DD floppies whatsoever.

Googling around I found this thread: https://eab.abime.net/showthread.php...t=4000T+floppy

Ignoring the discussion about that PCB, in the third post, which contains his second photo, if you look at that blue cable. I have that exact same blue cable (without twist). His DF0 and DF1 arrangement related to the cable (what is plugged into which connector) is also the same. The only difference is that in my case, the Gotek is at the bottom as DF0 and the Chinon is at the top at DF1 and not the other way around as it is in his setup.
Direct link to that photo: https://eab.abime.net/attachment.php...4&d=1542395640
I guess that I don't have some wierd non Commodore, after-market cable.

I'll borrow the floppy ribbon cable from my A3000D and see how both DD and HD floppy-drives behave then.

Edit: I wired up my A3000D's ribbon-cable. AmigaTestKit still says "No READY signal: PC or Escom drive?" but it can read and write HD floppies flawlessly now.

I can't use an A3000D floppy-cable as it's too short for an A4000T, but at least it proves that the HD drive is fine and "the twist" indeed solves all problems. Everything works exactly as it should.

I know that Escom/Amiga Technologies cheaped out on floppydrives and installed DD drives in their 4000T's but that blue-cable, that i've now seen on photo's from several people, is crap. It does work with two DD drives but DF1's LED's lights up when DF0 is doing things. A DD and a HD drive does not work because the HD drive only works with DD floppies (and before anyone starts, jumper J250 was correct for the tests the entire time).

so, i now need to find a long enough dual-floppy cable with the twist or..... take out the hobby-knife and create that twist in my blue cable
(the twist = from the last (DF1) floppy-connector's perspective, swap pin 4 with 6. Pin 5 stays as it is)

[mgfalc]

I had the same issues on my 4000T where it wouldn't work when I replaced the floppy disk drive with a Gotek.

I found that the pc floppy drive interface unit (the pcb you mentioned) that sits between the floppy drive cable and the disk module board was the first problem. I removed that, and it worked, being back to normal 'Amiga' drive mode. I must have one of the later crappy PC floppy disk drives, and the PCB is used to get that drive to work.

The second issue was the blue cable as it doesn't have a twist in it at the end of the cable. It's okay when you only use on drive on the cable, but with two drives it won't work properly. You can adjust the blue cable to put in a twist, or buy a cable from amigakit if you want two drives. I only want one drive in the 4000T, so the blue cable works for me