shmups.system11.org

Howdy!

For my fm towns Marty I am trying to work on its power supply (Tamura version!!!).

Since I have to wait for my replacement ELCO's for quite some time I decided to try and unravel the schematics for it (I think they don't exist on the web)

Here they are... I was wondering if some PSU gurus could take a look at them since I am not sure they are entirely correct


Furthermore... I decided to get crazy, remove all components and scan the empty PSU pcb. This way I can use it's dimensions to create a pcb in Eagle that uses the original on/off switch, AC mains input and metal bracket but has modern power Modules installed on it. In theory we could have a "drop in" PSU without the need to cut into the case.

Solder side


Component side


Curious to see what you guys think. I'll make the Eagle file public as soon as they're done

Cheerz!

Neat, I am a fan of clean drop in PSU replacements like this for vintage Japanese computer systems. Someone did a similar thing for the X68000 as well. While both my machines work well after I replaced their caps, it is nice to know there are neat alternatives to resort to in the future if need be.

Always makes me sad to see a laptop adapter hanging out of a system that originally came with an internal PSU. Especially if getting the whole wonky thing to work the owner had to hack things apart, leaving a general mess.

Here is what I have so far.

The power switch, AC input and metal bracket will need to be stripped from the original PSU, unless I can source them. Even though the power modules have their own build in protection I decided to go with a fuse anyway. Wouldn't feel good without it. Also added some caps on the output lines to filter a bit more ripple away.

Top


Bottom

I suppose that since the Marty is just a FM Towns386SX PC in a smaller box this replacement PSU design should be relatively easily translated to work in regular FM Towns computers as well. They have really dodgy PSU’s, let me tell you.

The form factor would be different but I imagine the output voltages and general functionality should be the same.

I don't think the output voltages are thesame. I have no experience with the FM towns PC's, but from the little info I read they require +5V, +12V and -12V. The marty is on +5V, +9V and -9V. Not that it is harder to create those voltages since it is a matter of putting on the appropriate power modules. Creating the dimensions of the board is easy enough. My main motivation was the fact that this machine was designed for Japanese voltages. I'm on 230V here, so with the re-use of some of the original components the idea is that the outside of the console is unchanged while I will still be able to directly connect it to the mains without a stepdown transformer

I made some progress on the Marty uni psu. As you can see, this is what it became. Unfortunately it did not revive my Marty and I will have to resort to reflowing as my next step to get my unit workin again. As soon as I can verify that this psu works I can upload files and part numbers. As you can see it is a non invasive, fully reversable mod.

That is very sleek. I am tempted to do this mod on my own Marty, even though the PSU in it is fully functional. It would make sense since it is multi voltage and I live in the 240V part of the world.

Can you tell me more about the replacement parts? Where do you buy them, what is their cost?

At the moment I am struggling to get my Marty to work (gives me NMI interrupts during boot) but I'd like to test run this first a bit to ensure there is no funny business going on. The components are rather simple. Just a 2A fuse, a 5V power module, 2x 9V power modules en 3x 470 uF caps on the output lines. Designed the pcb in Eagle and presto... one drop in Marty psu.

As soon as everything checks out theway I want it to I will upload the board files (or I might even do a small run of them) and the exact component list.

Okidok, following this project with great interest. If you need help with testing let me know.

I had the Marty running for a full day on this powersupply. No problems. Discdrive was playing a cd and constantly active. Shoot me a pm if you are still interested in testing. I have a board left and a quick guide with BOM to assemble it

I am interested in this

As a soon-to-be owner of FM Towns Marty (in Europe), some kind of Universal PSU would be very interesting. Could this be available to purchase somehow some day?

Extremely interested in this PSU. Any chance of buying a board or getting the design files?

This is some amazing work!

Thank you very much

Board files will be released of all the projects I've done. So far this is:

- NEC PC-fx uni PSU (universal power supply)
- fm towns Marty uni PSU (universal power supply)
- Intellivision uni PSU (universal power supply, work in progress)
- Atari Lynx LIPO qsb (10000mAH LiPo battery board)
- Videopac G7000 rgb mod (very small rgb board. Solders directly to the motherboard)
- Intellivision PAL rgb mod (based around an adv7125. PAL only. Work in progress)
- Casio Loopy rgb mod
- Bandai Playdia rgb mod

I will release all these files in one go on a new website I'm building that covers all my endeavours in hobby electronics and retro gaming. It will include BOM's and installation tips and tricks. I hope people will be able to use them and improve upon them

Wow... just wow!

I can use all but a couple of those mods on my collection. Looking forward to the website release.

Cheers!