Hello all! (However many are in this Tandy 1110 HD forum, I'm unsure of, but nonetheless, hello!)
I'm new here, but I have been taking a look into trying to replace the hard drive in my Tandy 1110 HD. While you
could get a replacement Conner drive every time your old one died, there's only so many of them left, and your wallet will be burning when you're done. I have an 2.5" IDE2SD converter I bought many years back. When I put it in and turn on the Tandy, I have to wait about two or three minutes before I get, "hard drive initialization failure; press any key to continue".
I have made some progress (I think) on the front that the interfaces are different. It seems that 2.5" IDE and Conner's 2.5" IDE are slightly different pinouts.
So let's get started!
2.5" IDE (Everything else):
Pin 21 - DMARQ (DMA Request)
Pin 27 - IORDY (I/O Ready)
Pin 29 - DMACK (DMA Acknowledge)
2.5" XTA (Conner Drives):
Pin 21 - Reserved (Something)
Pin 27 - DMACK (DMA Acknowledge)
Pin 29 - DMARQ (DMA Request)
There are some other pins there that differ, but they should not matter for our intentions. So if we splice the wires together (IDE Pin 21-XTA Pin 29, IDE Pin 27-XTA Pin 21, and IDE Pin 29-XTA Pin 27). After I did that, I put in the cable back in, minding the required new orientation of the cable, with the hard drive. I turned on the Tandy and noticed that instead of taking three minutes, it
IMMEDIATELY gave me the aforementioned "hard drive initialization failure".
My new hypothesis is that the hard drive
MUST have a capacity of 20 megabytes as seen in resource three below. We may be able to make a massive HPA on an SD card or CF card, or a 2.5" IDE hard drive, so the drives show up as 20 megabytes. Firstly, however, I will need to purchase a hard drive reader tomorrow. Anyways, hopefully I'm on the right scent to success, but we will see when we see!
~ Yours truly,
volatilememory
Resource One (2.5" IDE pinout):
https://zwopi.blogspot.com/2012/07/igel-geht-fremd-sd-statt-cf.html
Resource Two (Conner CP2024 info):
https://stason.org/TULARC/pc/hard-drives-hdd/conner/CP-2024AT-21MB-2-5-SSL-IDE-AT.html
Resource Three (20MB capacity):
https://forum.hddguru.com/viewtopic.php?t=22559&mobile=mobile