[Coladam] Floppy Drive Controller Chip

Jim Notini jnoti2 at comcast.net
Wed Nov 16 04:39:57 CET 2011

Homefully Bob S. or Rich C. can help with replacement parts, but these 
drives are getting so scarce that people are holding onto their own 
defective drives in case they need to raid it for parts.

I had the same problem with one of my drives back in 1985... reads but does 
not write (acts like the write-protect tab is on). Fortunately a friend of 
mine was an electronics wiz and knew that the problem was the 
photo-electronic cell (looks like an LED light) that is mounted on the left 
track and lines up (obviously) with the notch in the  5 1/4" disk. Since 
there were no repair avenues back them and and I had no clue where to get a 
replacement... he removed the cell from the hole in the track and anytime I 
needed to write to a disk I simply shinned a flashlight in the hole that the 
sensor at the bottom of the track would pickup. Fortunately, a couple years 
later Disk Drive Upgrades/Repairs became available.

There were a number of upgrades (5 1/4" 320K, 5 1/4" 360K and 3 1/2" 720K), 
but no one seems to have the upgrade chip available anymore. There were also 
some other modifications that needed to be done and maybe Bob S. has the 


----- Original Message ----- 
From: "Matthew Hudson" <hexsane at gmail.com>
To: <coladam at adamcon.org>
Sent: Tuesday, November 15, 2011 5:38 PM
Subject: [Coladam] Floppy Drive Controller Chip

> I'm looking for a replacement drive controller chip. Drive reads but
> doesn't write and I've traced it back to the 6801 controller chip in the
> drive. Anyone have one of these anywhere?
> Were there not upgrade chips available that allowed these drives to be
> upgraded to a 3.5" floppy drives at one time?
> -Matt
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