TRS80 Model 4 Rebuild - Part 4

The TRS80 Model 4 works well with the two internal 3.5" drives.  The challenge is sharing files with the other two stock machines which have 5.25" single sided floppy drives.  

In the future I plan to add a compact flash or sd card based "hard drive" to the top drive bay so don't want to install an internal 5.25" drive.  

The Model 4 has an external drive connector so I went searching for a suitable external drive case.... and Trade Me (the New Zealand equivilent of eBay) turned up 70GB DLT drives for less than $10.


The DLT drive occupies a full height 5.25" bay so the case supports 1 full height or 2 half height drives.  It also includes a small switching power supply providing +5V and +12V DC.  

I replaced the DLT drive with a Tandon TM-50-1 drive that was originally in the Model 4 when I first received it.  In the remaining space I installed a hard drive frame from an parted out HP-9000 minicomputer.  The frame holds Frederic Vecoven's Hard Drive emulator (


A very simple and successful project.  Now I need to find suitable cleaning product to remove the marker on the front of the case.


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