Help with an external drive issue

[scottmcc]

Hi all,

I have always been grateful for the vast range of info and expertise on the forum and generally I am able to troubleshoot issues from these existing resources but I fear this particular issue is going to require some direct expertise!

So, I planned on using a slim external drive casing as a neat home for a Gotek drive on my Amiga 600. This all worked great at first but now I have somehow managed to kill the external unit! I can only assume I have perhaps unplugged it without powering off properly first when I was messing around at some point but I can't be sure. Just to note the drive enclosure has no markings so I can't be sure of make or model. The disk drive is Citizen OSDC-65C.

I have trouble shot the issue as logically as I can:

- the Gotek and the external floppy drive work when plugged directly into the A600 so I don't think the problem is with the devices but rather with the enclosure;
- another external floppy drive works on the disk drive port of the A600 so I am hoping that means that I haven't screwed the disk drive port on the computer;
- the switch on the external drive circuit board seems to be OK - multi-meter shows left pole always at 0v, centre pole at 0v when in "Off" position and 4.8v when in "On" position, and right pole always at 4.8v
- continuity checks from the external disk drive end of the cable to the 24 pin headers on the circuit board all seem to check out;
- the board and the few components that are on it all look pretty clean and without any obvious signs of leakage or burns.

The only thing that I can discern that may point to an issue is that the header on the floppy drive power that I believe should be 9v (highlighted with an arrow) is only showing 4.8v on the multimeter.

I am a rank novice when it comes to electronics so some (or all) of above may be singularly unhelpful to anyone who does know a bit but I have basic multimeter and soldering skills and more than happy to provide whatever other info would be of use so please ask away.

Thanks in advance!

Scott

[Jope]

One side of the header is +5V and one side is +12V. The 12V side is often not connected at all, since most slimline drive mechanisms do not need it.

It's not always guaranteed that the orientation of the id/motor latch board's connector is the same as in the floppy drive, so you should definitely measure this before hooking anything up.

The Gotek does not need +12V for anything, it is happy with five volts.

Perhaps one of the TTL chips is fried and that's why it doesn't work. When the external drive is connected, can you see a DF1 in the early startup menu? Are there also a ghost DF2 and DF3?