tandy fd500

[286user]

I have a dual drive tandy fd500 that is part of a number of old tandy computer stuff given to me. I also have a color computer 2 for it, but unfortunately i dont have the cartridge that is needed for the floppy drive unit. Anyway
I plugged in the dual drive unit and flipped the switch to on, in back of it, i get no activity whatsoever. Ive never owned a a color computer setup before but since ive used commodore stuff such as the 1541, i do know when you first turn it on the motor spins up and there is a power light in front. I know the fd500 doesnt have this, but the dual drives do have activity lights for the floppy drives. So am i right to assume that when you switch the power to on the drive should be showing some sign of activity such as the motor spinning up etc? Since i dont have the controller cart to plug the drive into, i cant check the drive further. I did open up the unit the 2 big capacitors on the power circuit look fine, the fuse isnt blown nothing i could see out of the ordinary. Since ive never used a cc setup before, the drive doesnt have to be plugged into the cartridge controller and inserted in the cc to get drive activity on power up right?

 

[lafos]

My experience with external drives on TRS-80 is that they don't do anything when power is applied until they get a signal from the controller. This has been true with the original Shugart 35-track drives and all drive assemblies I have built over the years. Some drives will spin the motor when a floppy is inserted and the latch engaged to help seat the disk on the spindle.

 

[Eudimorphodon]

My experience with external drives on TRS-80 is that they don't do anything when power is applied until they get a signal from the controller. This has been true with the original Shugart 35-track drives and all drive assemblies I have built over the years. Some drives will spin the motor when a floppy is inserted and the latch engaged to help seat the disk on the spindle.

This. As noted, some drives, usually newer half-height ones, will automatically spin briefly to seat an inserted disk when the latch is closed, but that's it. Tandy used "dumb" Shugart drives which are completely controlled by the controller IC in the interface board; they accept low-level commands (which are simply communicated via individual control lines turning on and off, there's no "protocol") to turn on the motor, step the head in and out, etc, and that's it. Commodore drives like the 1541 have a complete self-contained computer onboard that actually runs the disk operating system and communicates via a high-level serial protocol to the host. In other words, they have the brains to run a full initialization/self test when they turn on, which the Tandy drives do not.

Even if you did have the controller cartridge because the Color Computer boots entirely from ROM it won't do anything with the disks until you do run a command from BASIC. It's been a while but I don't recall it automatically doing any probing of the disks on power-on, at least with the standard Tandy DOS. (There were alternative ROM DOSes, I think *some* of those may have offered the option of automatically looking for, say, an OS-9 boot disk?)