Hi all --

Against my better judgement I picked up a TRS-80 Model 16 last week. Initially it wasn't working at all, after replacing the Z80 CPU and CTC chips and doing a pretty thorough cleaning of the drives it seems to be happy.


It came with a 15 meg disk system which isn't faring so well in my attempts to get it running again. This has what I believe is referred to as the "Type 2" controller in it (http://nemesis.lonestar.org/computers/tandy/hardware/storage/mfm.html) with the 8x300 processor. The original hard drive in the enclosure(a Tandon TM-503) is toast. The bearings are shot, so it sounds like a circular saw when running and the drive never goes ready. I followed directions to replace the hard drive and work around the odd write-protect modifications (See: https://ia601707.us.archive.org/10/items/TRS-80_HD_Bubble_Repair_19xx_-/TRS-80_HD_Bubble_Repair_19xx_-.pdf) and after replacing the original drive with a Seagate ST-225, the Model 16 sees the drive and is happy with it.

However, I'm unable to format it. The controller doesn't appear to actually be laying down a format and attempts to read sectors after formatting fail with "ID Not Found" errors. I've tried several other known-working drives (another ST-225, a CDC 94025-51, and an ST-238 with the same results. (And yes, the terminator is present and accounted for on all drives.) I've run the Model II/12/16/6000 diagnostics and the controller passes with flying colors, as does the rest of the system.

Before I start digging in deeper to figure out what's going on, I'm curious if I've missed a step here. I know I'm not the first person to attempt this, anyone have any ideas?

Thanks as always,

Josh

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