jr-IDE is an open-source kit designed by Alan Hightower from retrotronics.org for the IBM model 4860 PCjr. The original Release, the Rev.A has been discontinued by TexElec and we created an updated version of the board. It is functionally identical, and only lacks the POST display from the original design.
Other differences include:
- Replaced DS12887 with DS12885 Real-Time Clock, added a user-changeable battery
- Redesigned to use more surface-mount parts, for lower profile
- Expansion Header added for Lower Cost addon boards
- IDE pins reoriented to use a standard IDE right-angle IDC keyed box header
- Capacitor added for power on pin 20 IDE jumper to help with CF card stability
All other original features of the Rev A card are also included on a sidecar board:
- 40-pin Parallel ATA IDE interface
- 1MB of static RAM
- 128KB of flash ROM
- A real-time clock
- Bus activity indicator LED
The expansion port will allow you to add our newest sound card, the Resound jr OPL3 / Adlib clone. For more information, please see the product description here: https://texelec.com/product/resound-jr-opl3-adlib-pcjr/
The jr-IDE includes pass-through mounting holes allowing it to fit into a standard IBM side-car enclosure. The IBM PCjr side-car bus connectors (AMP 532773-2 & 532771-2) are very hard to find parts, but already installed on our pre-built board. You may supply a donor shell from another sidecar, or alternately, use it stand-alone. The process is completely reversible if you decide to remove the jr-IDE from your system and return the shell to its donor card.
Alan developed this board and sold them in kits and assembled them for many years now, but the time has come for him to hang up his soldering iron on this project. We decided it would be a perfect product to add to our existing PCjr lineup. A special device is required to program the Atmel CPLDs and the side-car connectors can be very difficult, if not impossible, to purchase in single quantities. It seems the vast majority of units Alan sold were preassembled, so we decided to only sell them fully assembled and tested and ready to go.
The PCjr is a fun little computer, and the jr-IDE makes it much more fun to use without sourcing increasingly expensive original parts. You may use a 40 pin IDE to compact flash card adapter to use a standard CF card as a hard drive. Many older IDE hard drives may function as well. Your experience may vary, and experimentation could be required to find an optimal device to use as a hard drive. As always, we recommend the SanDisk Ultra II cards.
Main site for the jr-IDE – https://www.retrotronics.org/home-page/jride/
Clock set / reset utility – https://www.retrotronics.org/download/jr-ide-clock-utility/?wpdmdl=1545
The project genesis happened on Mike’s terrific PCjr forums in this thread – http://www.brutman.com/forums/viewtopic.php?f=1&t=180
Information on how to use later DOS versions on PCjr – https://www.brutman.com/forums/viewtopic.php?f=3&t=224
3D Printed Sidecar Case from Chuck over at IBM PC JR – https://www.pcjribm.com/phpBB3/viewtopic.php?f=45&t=11