1000EX 5.25 Floppy Drive Issue

[centrespot]

Hi All

I have a Tandy 1000EX which I'm trying to get working, it powers up and gets to the message asking for a system disk.
I have :-
Bought a set of disks from a supplier in the USA who checks the disks on their 1000EX before dispatching.
Already tried several MS-DOS disks but I always get the same message "insert system diskette"
Bought and changed the floppy drive controller chip.
Bought and tried another TEAC FD-55BV drive unit but it gets the same message.

Both drive units were cleaned before trying any disks and I have also tried using other cables from the motherboard to the drive unit.

I'm at a loss as to what I should check next, can anyone please advise.

Thanks in advance

 

[Great Hierophant]

What does the drive do when you power the system? Does the drive activity light turn on, does the disk spin? Do the drive heads move?