HP 9133/9134/9135 service manual

Tony Duell ard at p850ug1.demon.co.uk
Thu Jun 2 17:05:53 CDT 2005

> At 12:53 AM 6/2/05 +0100, Tony wrote:
> >> 
> >>      David Bryan just scanned and sent me a copy of "HP's 5 1/4-Inch
> >> Winchester Disc Drive Service Documentation" (HP 
> >> 09134-90032, August 1983) for the old style HP 9133/9134 and 9135 disk
> >> drives. Besides the always useful service information, it includes
> >
> >For suitable values of 'useful' ;-).
>    All service manuals are useful, some are just more useful than others!
> (And some are only useful for TP.)

:-). But you can't use a pdf file as TP, and you might as well not waste 
time and tomer printing it out if you're only going to use the paper for 

The _worst_ service manual ever has to be the one for the Torch XXX. It 
is a total waste of paper. No schematics, an _incorrect_ block diagram 
(IIRC it shows the main memory as being shared between the 68K side and 
the 'service processor' (a 6303 thingy), when in fact it's the video RAM 
that's shared [1]. Oh, and a useless 'glossary' with definitions like : 

IC : Integrated circuit. One of those black things on legs on a circuit board

ICs : More than one IC

I am _not_ joking

Needless to say I produced my own set of schematics for this machine...

[1] The boot sequence is actually quite clever. There is a single 8 bit
wide EPROM, whuch contains the service processor code and the 68K vectors
and bootstrap. At power-on, the service processor holds the 68K in the
reset state and copies the vectors and bootstrap into the video RAM. The
68K is then started, with the video RAM at the bottom of its memory space,
so it reads the vectors and starts as normal. It then recofigures its
memory map to put the video RAM somewhere out of the way and reads the
disk boot blovk, etc, into main RAM. 


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