Floppy drive microswitch issues

[plat]

I'm not sure about the best place to post this since it's not model-specific but I am encountering it working on some compacts so put it here.

I am trying to fix an HD drive with a clear issue with the microswitch that detects disk insertion. I took the bad switch off and tried to put on another from a donor drive (same type) drive. In the process of doing this the middle pin on the donor switch has gone missing. I'm not aware of breaking it off, it's like it was never there although there was solder corresponding to it on the board and I know this switch worked on the drive. Seeing that the switch worked with the two remaining pins (their connection is switched by the switch) I tried to put the switch in anyway but it does not work at all, no response to disk. Then I looked at the bad switch and saw that the pin missing from the donor is apparently hardwired to one of the other two pins, so I jumped those pins on the drive but still no response.

Now in testing the bad switch it seems to work with the middle and one end pin tied together and the other end pin switched relative to both of those by the switch. So I'm wondering if that is actually how it should work or one pin should be normally closed and one normally open?

I guess wondering how to determine for sure which switch is good if either and if not possible substitutes? Thanks.

 

[bibilit]

Not clear to me but the switch should be normally open when there is not disk inserted, and closed when the disk is in, and the to carrier is in the bottom position.

Your best option is to have a copy of the schematics and using a multimeter, have a look at what trace goes where and see what's happening when the switch is pushed down.

 

[plat]

I never thought about it being available before but a schematic would be great, I will be looking one.

I did find out more from experimentation though, apparently I had mixed up the switches and was still trying to use the bad one. And determined that it is as simple as you would think with the middle pin having no function except physical support and the two end pins a simple normally open switch.

Something else is apparently wrong with the machine because it still doesn't behave right with the new drive but that's another topic.