Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!hellgate.utah.edu!cc.utah.edu!cc.usu.edu!slsw2
From: SLSW2@cc.usu.edu (Roger Ivie)
Newsgroups: comp.os.cpm
Subject: Re: 3-1/2" disc drives
Message-ID: <16392@cc.usu.edu>
Date: 10 Jan 90 01:16:46 GMT
References: <1388@atha.AthabascaU.CA>
Lines: 34

In article <1388@atha.AthabascaU.CA>, tech@cs.AthabascaU.CA (Richard Loken) writes:
> I recently embarked on a project to put 3-1/2" 1.44 Mbyte wafer drives in my
> dear old TRS80 Model II.  I randomly purchased 3 Panasonic drives and got out
> my dentist pliers and got the pinouts and some jumper info from Matsushita.
> 
> 
> 	AT - PS2	(gag, yuck, my trash-80 may reject them)
> 	A - B
> 
	AT - PS2 probably governs the operation of the Diskette Changed/Drive
	Ready line. ATs need diskette changed, and I had assumed that PS/2s
	did also.

	It is also possible that this controls drive selects in conjunction
	with the A - B option. ATs have a twisty in the cable so that all
	drives are jumpered as drive one. It is mildly possible that PS/2s
	do not, and the A - B switch would control the drive select (either
	0 or 1) if the thing is in PS/2 mode.

> How do you terminate these little rice boxes?  I see not a hint of a termination
> avenue.

	These buggers usually have high-resistance terminators (abt 3k)
	in them that are hard wired on. Since the terminators are high
	resistance, it doesn't really hurt to have two terminated
	drives in the system.

===============================================================================
Roger Ivie

35 S 300 W
Logan, Ut.  84321
(801) 752-8633
===============================================================================