|Re: Does the death of the lead storage battery mean the whole death of 9114B 3-1/2 Disc Drive?|
Message #3 Posted by Tony Duell (UK) on 29 June 2002, 4:00 p.m.,
in response to message #1 by Hiroshi Ito
You have to have a working battery fitted if you want to use the HP charger/battery pack unit -- the mains adapter on its own can't supply anything like enough current to run the 9114.
There are basically 2 things you can do when the original lead acid battery fails. The first is to replace the battery. Yes, the original (Panasonic?) battery is unobtainable, but you can get some Cyclon cells. These are cylindrical lead acid cells (2V each), and the 2.5Ah size (which is about the size of a D cell) is ideal for the 9114. 3 of them (giving the required 6V) are a perfect fit in the HP housing. Just wire them in series and connect the ends to the original battery wires. Incidentally, the same cells work in the HP110 and Portable+...
The other option is to remove the HP battery pack completely and run the drive off a specially-made mains supply. If you take out the complete battery module you'll see a 2 pin mini-Jones plug inisde the drive. I can't remember the polarity, but if you take the top casing off the 9114 then you can see thw wiring at the back of the plug. The red wire is the +ve one. Connect an (unregulated is fine) PSU giving about 6V at up to 2A (!) to this connector. The drive will run fine (in fact, it'll run 'for ever', unlike running it from the HP battery which is being discharged if the drive is in use, even if the charger is connected !).
I've made a PSU for a fellow HPCC member to do this -- most of the work was drilling the box. But IMHO if you really can't design one you probably shouldn't be working with mains....
Of course if you have a lab bench power supply, then that's ideal too (I have one for testing my homebrew projects, so it was easy to make up a cable to link it to the 9114...)
Oh yes, I have got (somewhere) the remains of a commercial mains PSU for the 9114 -- I think I was told it had come from Educalc originally. IT was a little square metal box with a fuse and neon lamp on the front. Well, when I looked inside I was _appalled!_. That thing violated just about every safety standard I could think off (components, including the transformer, held down by silicone rubber goo, not fixed firmly, no earth ground to the box, and so on). If anyone has one of these, I suggest they do something about it now before it kills them (or worse, kills their HP handhelds)