Pimp my byte – replacing the power supply of an MSX Hotbit 1.1.

Now we are about to reboot an old MSX Hotbit v1.1 (also known as white Hoitbit). Here is an image of the actual computer (what once was white now is kind of yellow), but lets face one problem at a time.

This week my goal is to replace the original factory linear power supply (known to get hot really fast and consumed a lot of energy, much more than it delivered), for a switched one (because I have a PC one lying arround). Another advantage of doing this is as this component belongs to 1.1 model, it stoped being produced in 1986, so this font is in the best scenario 31 years. The one I intend to use was made in 2010, a little yunger.

The next image we have the opened computer with the power supply to the right and the digital board plus the RF converter to the left.

The next image is the actual power supply that will be assembled in the computer.

In order to compare between power supplies, the next image features both power supplies, above is the old original and bellow is the new one (ATX).

Converting between each other is quite simple because Hotbit uses only +12v, -12v, 5v and GND, that are very easily find and common voltages in most power supplies.

The INB cable, also known as INIB, is used only to shut down the power supply in case the slot cover is flipped down with the power on. Honestly, I don’t mind to not have this feature.

What I did is remove this flat cable solder off the power supply and join them in the corresponding ATX cables: yellow +12v, red 5v, blue -12v and black for GND. It was also necessary to short circuit between the green wire and any ATX ground wire, to keep the power supply turned on.

Here we have the final result, the case is washed and the cooler is in place ( not the original, but one a little smaller that was lying around ). Everything in place using hot glue.

With everything assembled, here we have an image featuring everything working ( please ignore the terrible image quality because there are several problems to be solved, this was one of them ).