Getting WD1002A-WX1 to work in Tandy 1000SX with floppy drives not working

[swabs77]

Hi, this is my first forum post so forgive me if I do anything incorrect.

My brother acquired a Tandy 1000 SX and the insides was a rats nest with stuffing in it along with some corrosion. It still started up! I took it apart to try and clean it up a bit, but after putting it back together I am having a issue getting the floppy drives to work. When it starts up it doesn't have that floppy sound from both drives, the A: drive lights up and you can hear it spinning at a slow speed. It seems to try and read but doesn't physically read the disk. It then asks for a system disk. I have verified both floppy drives work in a different Tandy 1000 SX as well as the cable. I also tried different working floppy drives and cable on the broken machine and it does the same thing. I have reseated the FDC chips and that didn't change anything. I have ordered new FDC chips (UPD765AC and FDC9216) and they should arrive in a week. I'm not sure if that is the issue though because I have tried the same chips from a working Tandy 1000 SX and it still didn't work. The drives did work before I cleaned it so I'm guessing I did something to it. I have gotten a XT-IDE card to work on the machine and boot to DOS so I know the machine still works.

Thinking the on board Floppy Controller may be bad I bought a WD1002A-WX1 to see if I could turn it into a Floppy Disk Controller (I read on a forum post that it was possible). I followed the instructions to get the card to read IRQ 2 and I hooked up the 34 pin cable from J1 on the hard card to the floppy drives. This causes the drives to either stay lit or cause a 1701 on the startup screen. I have a feeling I am missing something (just being an amateur here). Would I need to use the 20 pin J2 and J3 ports as well to get the floppy drives to work? I have turned dip switch 2 off on the motherboard and that didn't change anything.

I just would like to get the floppy drives to work again so I can give this machine back to my brother fully working, so if there is a way to not use the hard card or use it I'm open to any suggestions. Is there other things on the motherboard that would inhibit the floppy drives to work? Capacitors or different chips?

I have spent a lot of time on this and any help would be appreciated. Thanks!

 

[mojorific]

Tandy SX uses a low-density drive format (360k for 5 1/4" drives, 720k for 3.5" drives). You can't use high-density drives with the onboard drive cables. Tandy's also don't use a twisted cable (like most floppy cables) to determine which drive letter (there are actually jumpers on the drive to select drive 0 or drive 1.

Also, the problem with using a floppy controller card is that competes with the onboard floppy controller. It may be conflicting with IRQ's, or memory addresses. Those cards were meant to be used with IBM PC compatibles (and well the Tandy is mostly compatible, there are some things it does a little different because it integrated things that were usually cards on other machines). That's what made it so popular - you didn't have to buy all these other cards (like floppy controller cards, memory cards, joystick cards, etc.).

If you are trying to get it to a working state, maybe skip the floppy drives and go right for an XT-IDE adapter with a compact flash card. The other option may be to install a Gotek or HXC floppy emulator. I'm sure there are guides on how to set that up as well if you have the patience to go that route.

Good luck!

Here's a good video that may help you find some good info: