TI-99/4A power supply replacement with modern DC version

[PhilC]

Hi All,

I got this idea primarily whilst modifying my MTX512 to use a Cisco DC power supply, so thought I’d do something similar for my TI-99 (the one I’m keeping, not the one I’m selling).

The TI-99 uses +12VDC, +5VDC, GND and -5VDC by converting two AC voltages provided by the external power supply which then gets converted to the required DC voltages on the in built Power supply board.

I want to keep the internal board in place as it contains a power switch for turning the computer on and off as well.

The new power supply I’ll be using is a Cisco ADP-30RB which will give us a pretty good regulated +12, +5 & -12VDC supplies. It also has a sense line which is used to enable the output from the power supply.

I’ve ordered a second power supply now for the experiment and will post the next steps as I take them.

[PhilC]

On hold for a mo whilst I fix my TI-99 :roll: