Powering the 9114B disc drive without a battery pack

[Tom Sherman]

The 9114B disc drive will not run off an AC adapter if its battery pack is dead and in place. Apparently the battery pack consists of three 2V cells. Has anyone tried removing the battery pack and powering the disc drive directly with a 6V AC adapter (not the HP 8V adapter/charger)? Can the electrical engineers among us see any reason why this might damage the disc drive? -- because, e.g., the AC adapter delivers (I suppose) rectified current rather than the steady DC of a battery?

Please excuse my ignorance/stupidity on these matters. I find it strange that HP built this large box of a floppy drive, called it portable, and made it unable to run without a rather heavy battery, which is now somewhat difficult to replace.

Thanks for your ideas and enlightenment!

Tom

[Dale Richmond]

I have had no problem powering my 9114B drive from a Radio Shack AC adapter. It is switchable from 3, 5, 6, or 6.5 vdc at 2.5 amps and is labeled as a digital camera power supply, part number 273-1695. The store also had all the adapters necessary to interface with the male plug on the drive. I have had no trouble using this adapter. The voltage is fairly well regulated. I prefer this to the new battery pack I insalled and charger supplied with the drive. Just set the adapter for 6.5 volts and away you go. Good luck ( make sure that you get the polarity correct). If you need help drop me an email.

[Vieira, Luiz C. (Brazil)]

Hi;

I've been wondering about it too, and I found one big problem on using AC adapters, even if they are completely safe and free of noise (batteries generate safe and free-of-noise voltage and current, most AC adapters don't). Disk drives need peak current demand when spin motors are switched ON and OFF, and batteries can hold this.

Imagine you're transferring data from your pocket system (HP41, HP7x, HP8x...) to a LIF formatted disk and, at the very moment the directory is being updated, it happens a power loss OR a spike. I know that a FAT or LFS based disk may loose the last file or, in some "hard" cases, the complete directory may be lost (depends on the software you're running). What would happen in a LIF disk? I cannot even think of loosing lots of information because of this.

Maybe I'm talking about impossible things, but I thought about this, and having a battery pack to keep voltage and current in any situation makes me feel better...

My US$ 0.05.

Best regards.

[Vieira, Luiz C. (Brazil)]

Hi, Dale;

I did not read your post when I wrote and post mine. Have you been in this situation, say, a power loss when writing data? The controller will just stop and show some sort of Interrupt Connection failure message, but I am worried about the media contents.

If you found a noise-free adaptor, that's great! I'm sure you choose the best way. My concerns are just for the media contents.

Cheers.

[Dale Richmond]

I have not had any problem with a power loss during a disk write however I would imagine that it would cause some or all data loss. The reason I prefer to use the ac adapter is that the battery capacity is small and will only power the drive for a short time. I am more concerned about the battery discharging to the point of causing data loss. This actually happened to me while executing the "DIR" function. When the drive would spin up the voltage dropped low enough to cause problems. I have a NEW original replacement Panasonic battery installed so it is not a degraded old battery problem. I would also agree that nothing beats battery power for a stable DC source. I was thinking of using a larger capacity battery and wire it directly to the drive but have had no problems with the AC adapter arrangenent. It has a 2.5 amp capacity and you always have the 3 battery indicator LEDs on even during the time when the drive spins up.

[Tom Sherman]

Thanks so much, Dale and Luiz. Very interesting!! I will give it a try with the AC adapter. Great to hear that Radio Shack has the necessary interface adapter.

Cheers and thanks again, Tom

[Dale Richmond]

Tom, the last time I was at my local Radio Shack they had changed the store layout and did not have half of the electronic / hardware selection they used to carry. Hopefully your local store has not been "updated".

[Tom Sherman]

Well advised. Thanks again, Dale. We are old-fashioned in Maine, so I have a chance to find it. If not, probably their large catalog will list it.

I just determined that the lower slot (the smaller one) of the battery pack is +. I would have guessed the other way around (I have not opened it up). Shows how naive I am.

Tom