Replace 3.5" drives in HP9122D/HP9133H

Tony Duell ard at p850ug1.demon.co.uk
Wed Feb 15 18:51:03 CST 2006


> 
> I am wondering whether it is possible to replace the ailing Sony 3.5"
> disc drives in both my HP9122D and HP9133H HP-IB units with PC 3.5"
> drives?

Personally, I think it would be a lot easier to repair the existing 
drives. The main problem with these is that the grease on the eject 
mechanism hardens, and the mechanism doesn't lock properly. If this is 
not caught in time, then the upper head will catch in the disk shutter 
when you eject the disk and will be ripped off the gimbal spring. If 
that's happend you're looking for a new head assembly (been there, done 
that). 

The procedure for stripping down the drive has been posted here and on 
http://www.hpmuseum.org/ many times in the past. Let me know if you want 
me to go through it again...

If you have electronic faults, you might want to grab 'my' 9114A 
scheamtics from http://www.hpmuseum.net (not the same site as above!). I 
included diagrams for the 2 common versions of the PCB (FC9, FC16) and 
the motor. 

> 
> These are the older Sony 3/4 height units with separate data & power
> connectors, model OA-D32W-10 (double sided). The data connector has 26
> pins. The power connector is standard 4 pin.

I know them only too well!

> 
> I located the pin-outs for these drives on a Japanese site, and found
> that I could match all but 3 signals to a 'standard' 3.5" disc drive: 
> 
> SONY OA-D32W-10				STANDARD
> 
> 1 Motor On			----->	10	/MOTEA - 0=Motor Enable
> Drive 0
> 2 Drive Select 0		----->	14	/DRVSB - Drive Select 0
> 3 Disk Change		----->	34	/DSKCHG - 1=Disk Change/0=Ready
> 4 Drive Select 1		----->	12	/DRVSB - Drive Select 1


Be casreful. IIRC the double-sided Sony drives use a binary encoded 
select scheme (i.e. they allow for 4 drives on the cable, selected by a 2 
bit binary number, not the 1-of-n code used on almost all other drives. 
This is clear from the schematics...)

> 
> 5 Disk Change Reset	----->	????

This is an input to the drive. you might be able to ignore it.

> 	
> 6 Direction Select	----->	18	/DIR - 0=Direction Select
> 7 GND				----->	GND	
> 8 Step			----->	20	/Step - 0=Head Step
> 9 GND				----->	GND	
> 10 Write Data		----->	22	/WDATE - Write Data
> 11 GND			----->	GND	
> 12 Write Gate		----->	24	/WGATE - Floppy Write Enable,
> 0=Write Gate
> 13 GND			----->	GND
> 	
> 14 Head Read		----->	????

There are many jokes based on confusion between 'L' and 'R' in Japanese. 
It appears they may be based on fact. That pin is 'Head Load' (and yes, 
these drives do have a head load solenoid).


> 	
> 15 GND			----->	GND	
> 16 Head Select		----->	32	/SIDE1 - 0=Head Select
> 17 GND			----->	GND	
> 18 Index			----->	8	/Index - 0=Index
> 19 GND			----->	GND	
> 20 Track 00			----->	26	/TRK00 - 0=Track 00
> 21 GND			----->	GND	
> 22 Write Protected	----->	28	/WPT - 0=Write Protect
> 23 GND			----->	GND	
> 24 Read Data		----->	30	/RDATA - Read Data
> 25 GND			----->	GND
> 	
> 26 Ready			----->	????	
> 
> Is such a retro-fitting exercise possible? One possible problem could be
> the rotational speed; I know the Sony drives spun at 600rpm as opposed
> to the PC standard 300rpm... Any comments and/or suggestions about the

That's the major problem. You would have to modify the controller to run 
at hald the data rate. Maybe the firmware would need modification too. 
Personally, I'd think it would be a lot easier to repair the existing drive.

> feasibility, as well as matching the signals of pins 5, 14, and 26?

-tony




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