Trouble adding hard disk to A600 - LED disk light stuck on

I'm revisiting my Amiga project after about a year. I started last November trying to add a PATA hard disk (or CF) to it, but after trying all sorts of things, gave up trying - though I got a lot of help, so thanks for that, here's the history - http://eab.abime.net/showthread.php?...70#post1123570 (I couldn't continue the thread as my account appears to have been deleted).

I had a bit more success this time around with the hard disk, but I still can't get it working. I gave up with the CF as I couldn't be certain the CF drive was compatible. I also have two PATA disks, but get the same issue with both.

Beforehand the PATA disk would not appear in the HDdisktools, but this time on startup to WB it did. I was elated! Nothing has changed on my A600. So I read the disk configuration, which came back with full manufacturer details, serial number and the correct disk size of 777MB. However, on reboot, the DH0:NDOS icon did not appear. I went to the disk tool again but all the settings were there as I'd put them in, so it's clearly saved the configuration.

I then rebooted again, but this time the disk isn't recognised at all. It came back here and there on future reboots, but now it will not appear at all once more.

So, my next step was to prep it in WinUAE. The disk was presented as IDE and initial partitions set as before. When I put it in the A600, it still wouldn't appear as NDOS disks. I even cut the red pin 1 cable in desperation, but no change there either. It doesn't appear in disk tools either.

The disk is fully working, it has no issue whatsoever appearing on my PC or within UAE.

I'm using Kickstart 3.1 v40.63 and have tried disk tools on WB 3.1 and 2.1. One note here is that though WB2.1 disk tools would recognise it on occasion, I couldn't create partitions. It would let me set them, but the application would just hang when I clicked OK and had to reboot the machine.

The elephant in the room may be linked to the 'Disk' light (not the Floppy one) always being on. This is regardless of if a PATA disk, CF, IDE cable or nothing at all is attached. I read somewhere that a chap with an A1200 was having the problem and that it could be linked to a failed transistor somewhere around the Lisa chip (on the A600 I'm guessing the equivalent is the Gayle chip). I got some schematics, but without a board view equivalent, I'm not sure really where to start with my multimeter if this is the case.

I even wondered if there may have been a short somewhere on the case or shielding, but that doesn't seem to be the case after having extracted the motherboard. I tried changing to the original ROM but that didn't work either.

Everything else in the Amiga works flawlessly. Colour output is good, external drive, internal USB drive, audio etc...

I've attached a couple of picture if this helps!

Many thanks.