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HP-9114A Drive - Printable Version

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HP-9114A Drive - aj04062 - 05-07-2011

Can anyone tell me if 4 D Cell batteries provide enough power to test the function on one of these?

I know the lead acid battery is toast so I hooked up 4 D's to it in a tray. It is a bit livelier than before, but the power light always blinks and the fault light stays on.

Power does sag below 6V (about 5.3V) when the test runs. Is that too low?

The case is open and I notice the drive does not spin. If the head is moved off home, it does return, but that's it.

Re: HP-9114A Drive - Gerson W. Barbosa - 05-08-2011

I tried both a 6V-1A and a switched 6V-2.8A power source but I haven't succeeded. I haven't noticed any voltage sag in the latter, but I was told the voltage has to be greater than 6.0V.

Edited: 8 May 2011, 12:31 a.m.

Re: HP-9114A Drive - Paul Berger (Canada) - 05-08-2011

Looking at the schematic created by Tony Duell I would suspect that if it sags down to 5.3V that the -PWR OK signal would go inactive this would likely inhibit much if the operation of the drive. I do not have a 9114A but on the 9114B the state of this signal is checked before most operations involving the diskette drive, I would not expect the 9114A to be a lot different. The schematic can be found at http://www.hpmuseum.net/document.php?hwfile=2718. As you may know the B model has 3 LEDs on the front that indicate the battery state, when connected to 6V only two of the 3 come on however when connected to 7.5V all 3 come on. The 6V supply I used is rated for 1.8A and would operate the the dive without issue however I did notice that when the motor started the voltage would sag a bit and one more light would go out. The 7.5V supply is rated for 2.5A and I do not notice any significant voltage sag with it. It seems the general consensuses is that a supply rated for at least 2A is required for operation without a battery pack.

Re: HP-9114A Drive - dinamarco - 05-08-2011

I'll check it.. But I think there are 04 batteries (4 x 1,2 V = 4,8V). Be carefull with excess of charge...

Re: HP-9114A Drive - Paul Berger (Canada) - 05-08-2011

The 9114s use a pack with 3 lead-acid gel-cells which have a nominal voltage of 2V per cell however when fully charged they go a little beyond that, which is likely why on a B you do not get full battery indication at 6V. Looking at the schematic for the B the full light would come on when battery is at about 6.3V. If the batteries that where used where alkaline batteries with a nominal cell voltage of 1.5V then 4 would equal 6V however alkaline batteries can only provide around one 1A of current which is likely why the voltage sagged so much. Five NiMH or NiCd cells would work better with a nominal cell voltage of 1.2V each and capable of a lot more current output that alkaline batteries.

Re: HP-9114A Drive - aj04062 - 05-08-2011

Thanks guys for leading me straight. I look all over to find a charger that would provide this power. I finally found one from my old Panasonic camcorder. Haven't used it in years. Now it's good for something.

It works and passes self test now. Now, I'm trying to format a disk. I activated the external drive (the 9114A) on the HP 110 laptop and everything seems to work as expected except it will not format a disk. I found 2 old Standard Density disks. I know I read that HD will not work.

Can anyone tell me what the right disk is? 720 KB Single Density?

Edited: 8 May 2011, 9:38 p.m.

Re: HP-9114A Drive - Paul Berger (Canada) - 05-08-2011

720K diskettes are the right ones. That is the formatted capacity, several of the diskettes I have are marked 1MB Double sided on the
shutter. The 720K diskette is not single density, it is a double sided double density format the 1.44MB diskettes that came along later are usually refer to as high density diskettes, and I have heard of them being successfully in 9114 drives, however the composition of the oxide coating on the diskette is different so results may vary and it may take a couple tries to get them to format clean, but I have not tried it as I still have a large quantity of 720K diskettes. What happens when you try to initialize a diskette? Is there an error message?

Re: HP-9114A Drive - aj04062 - 05-09-2011

I am not at the computer right now, so I am going by memory from last night.

The disk intitializes and the head travels back and forth (I know this as the cover was off) several times.

I tried several times. I thought it could have been from the read/write slider being in the wrong position, but I don't think that is the case.

One or two times it seemed to step slowly across the disk.

In either case, I believe it ended with a message such as "bad media" or "unable to format, Abort, Retry or Ignore?"

I tried formatting @ 720k on an old laptop I had and that didn't work, the drive didn't recognize the disk. I am going to clean the head tonight. I do have an old floppy disk cleaning kit.

Re: HP-9114A Drive - M. Joury - 05-09-2011


I am using 1.44 MB (2.0 unformatted) disks on both my 'A' and 'B' models. The trick is to format them on a computer first. Unfortunately I can't remember the exact options but it is something like: format A: /F:720. Now the bad news... I think that you have to have a Windows 2000 or earlier OS to accomplish this. Per MS Windows XP (and I would assume the same is true for Vista / 7) will not accept the /F:720 switch. See MS Support

A little bit of hunting came up with this:

How to format 720 KB diskette on WIndows XP.

See if this works for you. I would try it myself but my diskette drive is turned off in the BIOS and I can't reboot at the moment.

And finally, here is a source for the rechargeable battery if you need it. I replaced all 3 of mine recently and they appear to work fine. Usual disclaimers apply:

9114 replacement battery

Edited: 9 May 2011, 3:18 p.m.

Re: HP-9114A Drive - Eric Smith - 05-09-2011

For 3.5" disks, the difference in coercivity of the medium is relatively small, 600 vs. 750 Oe for standard vs. high density. Formatting them for the "wrong" density will generally work, though I wouldn't do it myself except in an emergency. The coercivity of extended density 3.5" disks (2.88MB format) is 900 Oe, but they are extremely rare (at least in the US).

For 5.25" disks, the difference is 300 Oe vs. 600 Oe, and formatting them at the wrong density (in either direction) is extremely unreliable. Note that the so-called "quad density" is actually double-density with higher track pitch, so you need standard density media for that, not high-density.