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HP Forum Archive 12

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9114B floppy drives.
Message #1 Posted by Christof (USA) on 16 Apr 2003, 1:58 a.m.

After reading the other thread on drives, I'm curious if anyone has tried using a modern 1.44 drive on one of these- would they be backwards compatible?

also- the drive in mine has a different model no.

MP-F52W-50

It is exhibiting erratic behaviour, but I'm not sure what the source of the trouble is. 72.7% of the time it passes self test (the rate is increasing, as it hasn't happened at all the last 12 times I've powered up)

When initializing:

It often produces an error "invalid media" with several new and several used 720K floppies. generally this occurs after writing for a while, at which point the machine starts trying to rapidly read or write to one area - fairly obgviously having some difficulty.

It's possible that a cleaning diskette could fix this, or that I can find some old macs. But I *have* several later model Sony drives sitting unused amongst my room of sun hardware....

I'm carefully trying to take the drive unit apart now to clean, we shall see what happens.

-Christof

      
Re: 9114B floppy drives.
Message #2 Posted by Vassilis Prevelakis on 16 Apr 2003, 4:04 a.m.,
in response to message #1 by Christof (USA)

 Christof (USA) wrote:
> After reading the other thread on drives, I'm curious if anyone has tried
> using a modern 1.44 drive on one of these [...]

Well, I guess you haven't been reading the other thread. If you were reading the other thread you would know how incompatible the 9114 drives are with modern drives :-)

Is the battery fully charged and capable of delivering the close to 2A current the drive needs? Try powering the drive from a bench power supply, or at least check the battery voltage while the drive is accessing the floppy.

Also, have you tried cleaning/lubricating the drive?

**vp

            
Re: 9114B floppy drives.
Message #3 Posted by Christof on 16 Apr 2003, 11:35 a.m.,
in response to message #2 by Vassilis Prevelakis

Ahhhhhhhhh, I was confused as to which models were being referred to.

that makes it harder.

I have cleaned the drive out entirely and had no improvement, I may find someone with experience aligning heads locally and try that.....

            
Re: 9114B floppy drives.
Message #4 Posted by Christof on 16 Apr 2003, 11:49 a.m.,
in response to message #2 by Vassilis Prevelakis

oh, btw. I did check the power, it seems to be fine - new SLA battery, too.

            
Re: 9114B Pinout
Message #5 Posted by Christof on 16 Apr 2003, 12:42 p.m.,
in response to message #2 by Vassilis Prevelakis

Does anyone have a full pinout of the drive in this case?

I maight be able, with a friend, to get something working with standard drives if I can figure out how to fake a connector.

                  
Re: 9114B Pinout
Message #6 Posted by Ellis Easley on 16 Apr 2003, 4:03 p.m.,
in response to message #5 by Christof

The 9114B drive has a 34 pin dual row receptacle connector, doesn't it? Tony Duell and I were discussing the use of some of the odd numbered pins on the 34 pin data connector to carry power to the drive. Here's what I wrote about the way it was done on some Sony drives that Tandy used:

"You can see on the PCB where there are places for optional zero-ohm resistors which either connect all the odd pins (except pin 1) of the data connector to ground or connect one group of odd pins (3,5,7,9,11) to +5V and another group (29,31,33) to +12V (all the remaining odd pins except pin 1 [providing a logic signal] are directly connected to ground). When the drive has the option for power on the data cable, the 4 pin power connector is deleted. Tandy used a data cable that ran to the first FDD first (remember that the standard IBM "twisted" cable has the connector for the first drive at the far end - better for transmission line termination with removable 150 ohm resistors installed on the drive at the end of the cable, but later abandoned, with permanent 1K resistors on all drives, and a shorter cable used), then after that first data connector (or possibly after a second receptacle connector to allow a second 3.5" drive of the same type), there are punches in the ribbon cable to isolate those odd pins on additional devices from the +5V and +12V coming from the motherboard."

The even numbered pins should be the standard Shugart bus:

2 -

4 -

6 -

8 - Index Pulse from drive

10 - Drive Select 0

12 - Drive Select 1

14 - Drive Select 2

16 - Motor On signal to drive

18 - Head Carriage Direction signal to drive - I think high=in

20 - Head Carriage Step Pulse to drive

22 - Write Data to drive

24 - Wrote Enable to drive

26 - Track Zero signal from drive

28 - Write Protect signal from drive

30 - Read Data from drive

32 - Head Select signal to drive - high=head 1 (top surface)

34 -

IBM's floppy disk drive controller generates two Motor On signals and two Drive Select signals assigned like this at the controller end of the cable:

10 - Motor On A

12 - Drive Select B

14 - Drive Select A

16 - Motor On B

These four wires on the cable are split apart from the other wires and twisted 1/2 turn between the two drive connectors so the connector nearest to the controller has the untwisted signals and goes to drive B, and the connector at the other end of the cable from the controller has the twisted signals and goes to drive A. Both drives have their jumpers or switches set for Drive Select 1 (signal on pin 12 selects the drive, signal on pin 16 turns on the spindle motor).

The signals I have described above are the ones used in the PC which had drives that only worked at low density and didn't have a disk change signal. On the AT there are two new signals - a Density Select signal from the controller to the drive that tells the 1.2 MB 5.25" drive whether to treat its diskette as 360KB or 1.2MB media; the i.44 MB 3.5" drive only listens to the sensor that detects the density hole in the diskette shell. I think the density Select is on one of the low numbered even numbered lines. The AT drives also provide a Diskette Change signal from the drive that I think is on pin 34.

Also, there is a fourth Driive Select signal.

                  
Re: 9114B Pinout
Message #7 Posted by Tony Duell (UK) on 16 Apr 2003, 6:19 p.m.,
in response to message #5 by Christof

Here's the pinout, but it won't do you much good. As I mentioned before, the 9114 drives (and those in most other HP disk units) rotate at 600rpm. A normal PC drive, rotating at 300 rpm will _not_ work without changes to the controller circuitry. You will find it a lot easier to repair the existing drive!. Anyway, the pinout : Odd pins : (1) RstDskChng (3)-(11) +5V (13)-(27) Gnd (29)-(33) +12V Even pins : (2) DskChng (4) LED on (6) DS3 (8) Index (10) DS0 (12) DS1 (14) DS2 (16) MotorOn (18) StepDirection (20) Step (22) WriteData (24) WriteGate (26) Track00 (28) WriteProt (30) ReadData (32) SideSel (34) Ready


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