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386DX-16 Industrial Single Board Computer - Keyboard Issues, etc.
- Thread starter IBM
- Start date
Chuck(G)
25k Member
Chuck(G)
25k Member
Yup, your battery in the "keeper" chip is showing its age. If you get the keyboard hooked up you should be able to bypass that.
You can save me a bit of time--what's the part number on the "Keeper" chip?
You can save me a bit of time--what's the part number on the "Keeper" chip?
Chuck(G)
25k Member
You've lucked out--sort of. The Keeper II is just a lithium battery. Datasheet here
They're not what I'd call "cheap" however.
You could probably replace it with a battery holder or an external battery. Just about any non-rechargeable 3.6V lithium should work.
They're not what I'd call "cheap" however.
You could probably replace it with a battery holder or an external battery. Just about any non-rechargeable 3.6V lithium should work.
The 8-pin header at the bottom of the board is the keyboard/speaker header (as diagrammed in an earlier post). Above the the 'Keeper II' board, should be a 4-pin header with two-pins shorted together (and possibly missing pin #3). If you remove the jumper You can install an AT-compatible CMOS battery [good luck finding one of those ... + = Far pin where jumper was installed, - = far pin on other end of header; the two inner pins will not be connected with an external battery].
The 40-pin connectors were for a memory expansion board [not many were sold so you are not likely going to find one].
The CPU board did not have any on-board serial/parallel/floppy/video hard drive connections.
On the DIP switch, switch 1 indicated whether the CPU expected a CGA (down) of monochrome (up) external video card. Switch 3 should force the board to clear CMOS at power up (down). I do not remember what the other two switches were used for.
The 1/8" jack on the rear of the CPU board was for an external speaker.
The "industrial" meant that it was built for extended temperature and shock/vibration environments (when compared to desktop computers). Being designed for use with a passive backplane meant that should the CPU board ever fail, you could 'quickly' replace it by removing the I/O bracket screw and the mechanical hold down bar inside the Texas Micro chassis (on some but not all). You than just remove the CPU board and disconnected the keyboard cable. You reversed the process to install the replacement CPU board. [I say 'quickly' since it was a lot faster than having to replace a motherboard out an existing PC.]
I do not remember off hand if this board had a watchdog timer. If it did, the jumpers to the left of the 'Keeper II' probably controlled whether it was enabled and how long before it waited before doing a hardware reset on the CPU.
Jeff Brielmaier
formally of Texas Microsystems/Texas Micro Inc./RadiSys
<< These comments do not reflect on any past and/or present employer >>
The 40-pin connectors were for a memory expansion board [not many were sold so you are not likely going to find one].
The CPU board did not have any on-board serial/parallel/floppy/video hard drive connections.
On the DIP switch, switch 1 indicated whether the CPU expected a CGA (down) of monochrome (up) external video card. Switch 3 should force the board to clear CMOS at power up (down). I do not remember what the other two switches were used for.
The 1/8" jack on the rear of the CPU board was for an external speaker.
The "industrial" meant that it was built for extended temperature and shock/vibration environments (when compared to desktop computers). Being designed for use with a passive backplane meant that should the CPU board ever fail, you could 'quickly' replace it by removing the I/O bracket screw and the mechanical hold down bar inside the Texas Micro chassis (on some but not all). You than just remove the CPU board and disconnected the keyboard cable. You reversed the process to install the replacement CPU board. [I say 'quickly' since it was a lot faster than having to replace a motherboard out an existing PC.]
I do not remember off hand if this board had a watchdog timer. If it did, the jumpers to the left of the 'Keeper II' probably controlled whether it was enabled and how long before it waited before doing a hardware reset on the CPU.
Jeff Brielmaier
formally of Texas Microsystems/Texas Micro Inc./RadiSys
<< These comments do not reflect on any past and/or present employer >>