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I have a 9114 that needs a new drive. The movable head has been bent up when someone removed a stuck disk (I suspect).
I suspect original drives are hard to find but perhaps some other system (Apple, IBM, etc) may use this drive. It is an OA-D32W-11 that was in this 9114.
Anyone know of another disk system that uses this drive type?
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The 9114A nad 9114B use different drives!. The drive in the 9114A is also used in many HP HPIB drive units (such as the 9133), and in some older Apricot computers.
The drive in the 9114B is also used in the HP 9153 (I think). I've never seen it used elsewhere, but many parts (head carriage, stepper motor, analoge ASIC chip, etc) are also used in the Apple 800K drive used on old Macs. That's a possible source of a head. But of course you'd need to align it after fitting (which is not hard, but you do need a 'socpe and alignment disk).
In your case, you need the first type of drive, from a 9114A. The head often gets damaged when the grease on the disk holder/eject mechanism goes hard. The disk holder doesn't latch properly, and the disk rips the top head off as it ejects.
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Tony,
In your post which I referenced in my response below, you said you could provide step-by-step instructions on removing the hardened grease from the drives in the 9121D/S and 9114A, et al. Have you or will you please? I have the HPCC Datafile CD-ROM that Jake Schwartz provides (Twenty Years of Datafile 1982-2001) - would it by any chance be there? MoHPC Articles Forum #78 cheers one on regarding the cleaning but doesn't provide specific instructions. I have a 9121 that I want to start using but I want to do the preventive maintenance first.
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I can get the drive unit out of the 9121 on my own, I just need to know the steps for getting rid of the hardened grease.
BTW, you mention that the 9114B drives have power on the 34 pin data cable - Tandy/Radio Shack used drives like that in the computers built by Tandy at the end and for quite a while before. I don't think Tandy thought it up, I'm sure Sony offered it that way. Both 720K and 1.44M drives like this were 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.
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Floppy drives with power on some of the odd numbered pins of the data cable (normally all grounded) are not that uncommon. I've seen them used in other machines. What makes the 9114 (and other HP) drive units unusual is that they rotate at 600 rpm (PC drives rotate at 300rpm).
So you can't use a PC drive in a 9114 without changes to the controller board.
The Sony drive in the 9114B looks to have been a standard unit, though. THere are soldered jumpers for power on the data cable .vs. power on a separate connector (and there are pads to fit such a connector). There are a couple of other soldered confioguration jumpers too. There even seems to have been a vesrion with a Mac-style motorised eject mechanism (!). That was never used in the 9114B, of course.
I don't know if the 600 rpm drives with 34 pin connectors were used anywhere else. Maybe there is some obscure machine that had them.
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I logged in this morning to add another ps. about the spindle motor speed! I'd like to know what HP's reasoning was for using 600 RPM. It cuts "average rotational latency" (1/2 the time of a revolution) in half but since HP's systems are so slow, you have to use a higher interleave (which means more revolutions to read a given number of sequential sectors) to improve performance. It all seems to add up to faster diskette wear.
Next time I open up my 9114B, I'm going ot compare the drive to the ones Tandy used - see how much is in common.
Doubling the spindle rotation speed also means the frequency of the read and write signals is doubled, possibly requiring different reactive components in those circuits - maybe even different heads. The actual doubling of the rotational speed is possibly a jumper option on the motor PCB, or it could be a ceramic resonator of twice the frequency on the motor PCB. Some 1.2MB 5.25" drives (not the original one in the IBM PC/AT) had two spindle speeds selected by a pin on the 34 pin cable - 360 RPM for 1.2 MB mode (500 Kb/s data rate just like an 8" drive except 80 cylinders instead of 77) and 300 RPM for the 360 KB mode (so the data rate would be 250 Kb/s, simplifying the FDC circuit). The drive used in the PC/AT only spun at 360 RPM; it used the same heads for data at 300 Kb/s and 500 Kb/s.
BTW, you mentioned non-Mac drives that look like they have provision for motorized eject - I've noticed that a lot of 3.5" drives have a rotary damper (loaded with thick silicone oil) coupled to the diskette loading mechanism via a rack-and-pinion gear mechanism. I think this is to make the head land on the media gently. It looks like a motor with the same pinion gear could be mounted in the same location as the damper.
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IIRC, the original spec for the 3.5" drive stated a 600rpm spindle speed. HP used such drives (they were standard Sony units, and I think Sony were the inventors of the 3.5" disk). The 300 rpm ones were introduced later, so they could be used with standard PC disk controllers...
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I believe there is an article in the articles forum that describes in painstaking detail how to get rid of the gunky grease and even repair the head assembly.
I am particularly sure because I remember writing it :-)
Steve
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Steve,
I read your article and I appreciate it. Tony had offered to post a step-by-step procedure for cleaning out the old grease, and with a mechanism like a 3.5" FDD, I really like having some idea on the order to attack disassembly!
I remember when I first saw a 3.5" FDD - the first ones were all from Japan - having been familiar with 5.25" drives based on the Shugart 500 (?is that right?) drive - even Tandy was building its own 5.25" drive - the 3.5's were so beautiful by comparison! So compact and precise!
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I don't think I ever wrote this up for Datafile, so it won't be on the CD-ROM. And it's a long time since I've done it, but I can still remmeber roughly what to do.
Adter taking the drive out and disconnecting all the external cables, take off any mouning brackets/plates. Then remove the one screw on the back and take off the top cover.
FLip the drive over. Take out the 3 screws on the 'foil' shield over the PCB. Take off the shield, then ease out the PCB (you will probably have to untagle the wires to the stepper motor). Unplug the connectors from the PCB and set the PCB aside.
Still working from under the chassis, take out the 2 screws at the very front. These hold the front panel in place. Remove this, taking care not to damage the LED or lose the eject button/spring. Put all these parts aside.
Back on top now. At the rear left, take out the screw holding the eject damper in place, and remove it. Note how the little white arm fits in place. Take out the 2 screws on the head load solenoid bracket (one holds an earth tag in place), and take the bracket out. Feed the wires through the chassis.
Again from the bottom, take out the 4 screws near the sides which hold the disk holder in place. Carefully free the hodler from the head assembly -- if this is a double-head drive put a piece of clean tissue paper (a lens tissue or similar) between the heads so they don't touch).
Take off the E-circlips on the sides of the disk holder assembly and separate the parts. Note how they go together. Clean the parts in a degresing solvent (start with propan-2-ol, use something stronger if this doesn't work) and remove the old grease. Apply a little new grease (I use Electrolube plastic grease, if only because I have it around), and put everything back together.
Incidentally, if it's a 9121, then it should have single-sided drives. There's no risk of ripping a head off with these..
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Thanks Tony! Sounds like a complete teardown. Yes, I have only single sided drives but the description of the problem sounds like a diskette could get stuck in there and I'd just as soon avoid it.
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First, this is on an 9114A.
Second, when I began to test the drive, before I knew about the head problem, I couldn't even insert a disk because the drive was stuck.
I opened it and found exactly what you say. When I degunked the mechanism but noticed the dangling head. So, apparently that is what happened. A disk must have been stuck at one time and yanked out.
Since I'll likely not find another drive, except from another 9114A, this will probably just be used for parts.
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Tony Duell (UK) wrote:
> The 9114A and 9114B use different drives!
Yes, but while their interfaces are not pin-compatible,
can an older drive be connected to an 9114B controller
via a modified i/f cable?
Thanks
**vp
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I suspect you can make up special cables to use the 'wrong' sort of drive with each controller, but I've never tried it. From what I remember of the pinouts, the 2 drives have pretty much the same signals..
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I searched the archives for "sony" - first I came upon your post about the 9121 FDD that needs manual diskettes - there you had a link to a site with info on that drive:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv009.cgi?read=25585
But I knew there was another discussion and I found it:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv006.cgi?read=10635
basically, Tony says:
"The grease-turned-to-glue problem mainly occurs in the older full-height 3.5" Sony drives, used in the 9114A, 9133, 9121/2/3, etc. "
"An old Apple Mac+ drive is one of the best sources of spares for the 9114B. "
You didn't say "A" or "B", sounds like "B" might be easier to find parts.
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