TI-99/4A PSU plug

I recently repaired a TI-99/4A computer and needed to connect power to it, but unfortunately I didn’t have the original power supply. Nowadays, it’s no longer possible to buy a dedicated plug for this computer, so I decided to model one myself.

The housing of the power plug consists of three parts, and you can print them without using supports because the model has been specially prepared. Below is the optimal arrangement of the components on the print plate.

Additionally, you will need 4 female MOLEX contacts, catalog number 2081201, and one flat-head self-tapping screw (3x6mm) or (3x8mm).

You can obtain the MOLEX contacts from an old ATX power supply for a PC or purchase them at an electronics parts store. Make sure they have two tabs, just like in the picture below.

Assembly:

1. The MOLEX contacts are slightly too small in diameter, so you need to gently widen them. The best way is to fit them onto the pins in the computer’s power socket. That’s how I did it.
2. Prepare the wires and crimp the contacts onto them. Spread the tabs of the contacts if necessary. Insert the contacts into the housing from the groove side. Due to your printer’s tolerances, it may turn out that you’ll need to enlarge the inner hole with a 3 mm drill bit. You can find the wiring diagram at the link.
3. Place the contact housing in the lower part of the casing. Tighten a cable tie around the wires to secure them against being pulled out. The diameter of the cable sleeve is 6 mm.
4. Place the upper part of the housing on and fasten it with the screw.

I hope you’ll enjoy the model and that it will help solve the problem of the plug’s unavailability.