Hi Adam,
Great little computer - congratulations.
The pop-out mouse is a little different, but still pretty ingenious for the time. I use my OB's only in MSDOS, CPM/86, or command line Xenix or Linux. So I really don't use the mouse much. But it is nice to have it, if I need it.
Maybe someone else here can correct me, but I don't think the OB-300/435/430 systems have a separate battery for CMOS. Several years ago, I opened up a broken OB-425 and did not find any CMOS battery. I'm assuming that they just use a capacitor to retain the settings. But I may be wrong on this.
As to the internal Hard Drive. These will fail - sooner or later. I have had a bunch of them and they all eventually failed. Plus they have a higher power consumption rate and are slower than a flash card. Recommend going with a compact flash card. This makes it easy to copy files to in a standard PC using a CF/USB adapter. While full size PCMCIA flash cards will also work, it's hard to find an USB adapter for them (to use with a PC).
Depending on the version of your ROM application card, you may be limited on the size that it will recognize. Later cards will recognize up to 512mb, but I think the earlier ones will only recognized 128MB (and I'm not really sure if this large). I no longer have my OB-300, but you may be able to use a larger card but only FDISK the partition to a small size. I have used up to 5gb flash cards/micro drives on my OB-430 with the MSDOS partition being 512MB.
Enjoy it and have fun.
Bill
Smithville, NJ
Hey, Bill! We discussed this topic on the HP Museum forum. As I said over there, it has the V1.0 ABA ROM card, but at least works with the 32MB Sandisk flash card I use with my HP 200LX (are those as fussy about flash drives as the ABA-ROM OB300 is?). A rather odd limitation, but hopefully I'll be able to work within it.
I figured the OB300 didn't have a built-in BIOS battery, but the mention of leakage had me worrying after what I've heard of happening with Apple Lisas and whatnot. The main battery pack in my OB300 has yet to leak, but I'm trying to take as few chances with applying charging current to it as I can. As I've asked before, is it OK to run one of these with the power adapter connected, but the battery pack removed?
What i really recommend is to use a larger flash card and the "OBMAX" utility which makes it easy to get rid of doublespace and other annoyances that just eat up RAM.
The ROM cards of the OB300 and OB425 are a bit...hmmm restricting. Which means if you install a different DOS they will just format the card and throw DOS 5.0 on it again. The OB430 does not have that "feature".
On the left side there's an expansion slot, but the only accessory ever released was a modem. Base RAM is 2MB, expansion RAM boards were available as 2MB and 4MB modules, so a maximum of whooping 6MB.
These units have a mind of their own, so if you ever find one not responding to turning on/reset then just leave it powered for an hour and try again, sometimes they just do that if you leave them alone for too long.
Yeah, I've heard of OBMAX, and will consider it if I successfully manage to change out the HDD for a flash card. The OB300 is rather restricting, but I'm not looking to bring this thing too far into the future, and I have somewhat of a fondness for Windows 3.1, so I'll probably keep it equipped as thus (unless I come across the ROM card from the OB430 for a good price or something, and even then, who knows).
I'm hoping to upgrade the base RAM to at least 4MB, but these F1041A modules seem to be rare outside of harvesting from a junker. What would happen if you put two 4MB cards in one of these? I wouldn't mind getting some of the more complex DOS games (like Wolfenstein 3D or the original DOOM) running on this thing for the heck of it.
Thanks for the pointer. I haven't seen mine randomly go unresponsive as of yet, but I'll definitely keep your tip in mind if it does. The only thing I've seen thus far which caused my OB300 to go wonky was when I tried running some 200LX-specific DOS programs on it. The screen went blank, and nothing happened. Pressing the reset switch brought it back around. Haven't had any issues thus far running more-conventional DOS programs on it.
-Adam