Retro Review: HP Omnibook 600C - Part 4

5th November 2025

 

Introduction

In Part 3, the OmniBook 600C got cleaned up nicely. Now to put it all back together and have a fully working and battery-leak free laptop!

 

The Rebuild

I replaced the plastic insulation over the top of the mouse daughterboard and made sure the spring and lever were attached. Then the motherboard went back into the case. At this time, knowing I lost many hours trying to get the keyboard ribbon cables reinstalled for testing, I put two small pieces to sticky tape across the gaps in front of the keyboard connectors - this was after losing the little white tabs numerous times in those holes and under the motherboard with failed connection attempts. This way, if they don't connect right and get pushed away by the cable, I can still grab them and retry without removing the motherboard from the case again!

The motherboard reinstalled, along with the mouse spring and button, PCMCIA eject lever, PCMCIA spring door, and the display and mouse cables reconnected

(Left): The top case and LCD screen reinstalled, and (Right): Notice I pre-positioned the left connector tab, but left the right one out for now

The pesky keyboard ribbon cables reconnected successfully

Reconstruction is complete!

The hard disk is still very unhappy - nothing I copied to it will run - it just hangs the machine and eventually returns with this red message - hitting A returns you to the DOS prompt, but I need to replace the hard disk

Here are a few pictures of the cleaned-up machine. Sadly the left hinge fix didn't last as I put the machine back together, and if anything it's now worse - it holds the LCD display section up at any angle, but creaks and bends whenever the machine is opened or closed - this of course is common with such old machines where the plastic has become brittle over time - I'll need to be very careful in future when opening and closing the unit.

I forgot to put the hinged cover on the back

 

OmniBook 600 Downloads

If you've read this far through, you'll recall I copied all files that were OmniBook-specific off the Integral hard disk. You can download these here, plus a few more things. Special thanks to David Collins over at the HP Computer Museum for his kind permission to host the PDF documents below. The HP Computer Museum is a wealth of historical information, pictures and downloads on a huge number of Hewlett-Packard products - I recommend you check it out!

Quick Start Guide for OmniBook 600 Series Courtesy of the HP Computer Museum	Operating Guide for OmniBook 600 Series Courtesy of the HP Computer Museum	Familiarization Guide for OmniBook 600 Series Courtesy of the HP Computer Museum
Technical Data for OmniBook 600 Series Courtesy of the HP Computer Museum	Introduction to OmniBook 600CT Courtesy of the HP Computer Museum	MS-DOS 6.20 System Disk for OmniBook 600 Series A bootable 3.5" 1.44 MB floppy disk image (.IMA format) that boots into MS-DOS 6.20 with all the device drivers
All OmniBook Files for OmniBook 600 Series A ZIP file containing all the OmniBook 600-specific files I could find on the machine. Includes device drivers for PCMCIA and mouse, Laplink Remote Access, HP PIM software, OBTEST diagnostic program, and more.	PCMCIA Windows 3.x Driver for OmniBook 600 Series A ZIP file containing all the OmniBook 600-specific files I could find on this machine	BIOS v4.01 Update Disk for OmniBook 600 Series A ZIP file containing the HP Windows 95 and BIOS 4.01 update disk **Only for those with BIOS v3.22 already and Windows 95** **WARNING: I will not be held responsible if you attempt to update your BIOS and it doesn't function as before - if it's working now, leave it alone**
ROM BIOS v3.1a for OmniBook 600C A 64 KB dump of the BIOS ROM area from F000:0000 - FFFF:FFFF. Created using Michael Brutman's DUMPPCJR utility with the -noheaders argument. **WARNING: I will not be held responsible if you attempt to update your BIOS and it doesn't function as before - if it's working now, leave it alone**	ROM BIOS v4.1 for OmniBook 600C A 64 KB dump of the BIOS ROM area from F000:0000 - FFFF:FFFF. Created using Michael Brutman's DUMPPCJR utility with the -noheaders argument. **WARNING: I will not be held responsible if you attempt to update your BIOS and it doesn't function as before - if it's working now, leave it alone**	VGA BIOS v1.1.4 for OmniBook 600C A 40 KB (40,960 bytes) dump of the BIOS ROM area from E000. Odd size, but it is correct. Created using Michael Brutman's DUMPPCJR utility with the -noheaders argument. **WARNING: I will not be held responsible if you attempt to update your BIOS and it doesn't function as before - if it's working now, leave it alone**
VGA BIOS v2.5.2 for OmniBook 600C A 40 KB (40,960 bytes) dump of the BIOS ROM area from E000. Odd size, but it is correct. Created using Michael Brutman's DUMPPCJR utility with the -noheaders argument. **WARNING: I will not be held responsible if you attempt to update your BIOS and it doesn't function as before - if it's working now, leave it alone**

The PCMCIA to CF card adapter that's been used in an Amiga 1200 appears to have gone missing. I have another one on order, and will try booting from a CF card when it arrives and update this page with my findings. From my research, It should work just fine in the PCMCIA slots but the primary hard disk slot is the one I want to confirm.

I hope you enjoyed this tour of the Hewlett-Packard OmniBook 600C! Let me know if you have or had one of these, and your memories of using it.