Indus GT

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Indus GT
Indus GT
Type: Floppy
Producer: Indus Systems
Price: ? US$
Released: 198?
Discontinued: 198?

The Indus GT is a Commodore 1541 compatible 5,25" disk drive. This unit offers some features not available on the Commodore drive. The floppy was produced by Indus Systems (9304 Deering Ave., Chatsworth, CA 91317).

Notice the front panel has a display panel and four buttons. The two LED displays are for track and sector, a Power LED, a Busy LED, and a Protect LED. The four buttons are: Protect, Drive Type, Track, and Error. Notice also there is a protective retractable panel.

This drive will basically do everything the 1541 can do and a little more. It does not suffer from the overheating problem as a separate power supply is used to connect to the power source.

Looking at the back of the unit, there are four serial plugs (two standard and two marked "Auxiliary", 4 DIP switches to set the device number (8-12) and adjust the auxiliary plugs, power plug, and the on/off switch.

One of the most notable features of the Indus GT was the track zero seek mechanism. On the 1541 drive a cog was press fit onto the head stepper motor shaft. Each time a specific command was issued that required a track zero seek the drive would command the head back to track zero which would slam a raised portion of the cog into a hard mechanical stop. The track zero seek was noisy and repeated and after a while it would twist the cog ever so slightly on the shaft. This had the effect of making floppies somewhat less than interchangeable.

A common fix for the 1541 was to disassemble the stepper assembly and mount the cog and shaft in a vise and drill a hole through the side of the cog and through the shaft. Once done a roll pin, trimmed slightly smaller than the depth of the hole would be inserted and locked in place with thread locker. The stepper and head assembly would be put back in place, a known good 'factory' floppy would be put in the deck and it would be commanded using peek/poke and I/O commands to read the center most track, halfway between the edge of the disc and the center. Using a multimeter with a very simple voltage detector (diode, cap and resistor) would integrate the read pulses from the head amplifier. Adjusting the stepper motor CW and CCW would allow you to find the proper track; too far one way and you were on the track either side of 40.

I believe that the Indus solved this problem by using optical limit switches. Much more elegant and never, ever had a problem with the drives again.