The FM Towns Power Supply Problem has been solved

Towns are known to have dodgy power supplies. For example simply changing capacitors doesn’t always magically fix them. Unless you’re a very VERY well trained technician for Switched mode power supplies you’re not gonna fix it. Sorry. Unless you like chasing down 25-30 year old chips and switches you’re probably not gonna fix that original power supply. Don’t believe me? Go to NFG forums and read those ancient posts about their bad power supplies.

Well luckily for you I have found a way to fix it all. I have learned what works and doesn’t work…trial and error….pain and sweat…basically I made a way to revive these old computers with a 100% success rate.

Above is the desktop model. It will work on all desktop variants provided you cut the wiring harness from your dead power supply and follow the instructions specifically from the BEEP manuals. Mr. Hota was very kind and scanned the manuals for me. Well we can use them to revive these dead computers. It seems that there are three different desktop power supplies. This works with two out of three families of desktops. FMV Towns I don’t know it since I don’t own it.

The Towers functionally work the exact same as the desktop minus the crazy wiring harness.

Both designs actually have regulated power which is something the original power supplies don’t have. Don’t believe me? Go ahead and measure your 12V rail if you’re plugged into the wall in USA. It’s going to say 15V. Now granted the motherboard has regulating components onboard to handle this overvoltage…but the stock PSU will be further strained which is why random ICs will die. Even your 110V stepdown you use in Europe will still strain this.

So by using Arduino micro pro you can retain the use of the original power button and still have TownsOS power off feature. Nasty ATX wiring mods are now a thing of the past. Check these two links with prototype.

The ACDC Converter of choice is the EPP-120S-12 which is the cheapest AC/DC converter I could find that can safely output enough power and 12V. Then it goes into a pico PSU and then into the computer. So the ACDC converter can accept between 80 VAC to 264 VAC meaning…

You won’t require a stepdown in Europe. You can plug directly into the wall! The only drawback with these two power supply cards is that it is very expensive to hand assemble but it is the silver bullet to solve the problems.

I will follow this up with an installation guide and hand-assembly guide later this week when the boards arrive from fabrication. I will probably want to sell a few before releasing design into the wild.

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