FM Towns 20F Repair Notes
The FM Towns PC was one of the very first 32-bit gaming platforms. Its visual design is a striking portrait of everything that was cool about Japanese technology of the late 80's and early 90's.
Ever since getting a first glance of the futuristic gray PC in Electronic Gaming Monthly #4, I have wanted one.
I must have read this page out of the magazine fifty times:
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| The article that inspired my obsession with the FM Towns when I was a kid. |
About 11 years ago someone offered a broken one for sale on Ebay. IIRC, it was just the PC itself, without a keyboard or monitor. When I reached out to him to ask about the potential of repairing it, the seller did not want to let me buy the broken one. He was an Australian living or visiting Japan, and he was evidently trying to make a little money on the side by selling what were common items in Japan but rarities in the rest of the world. He told me he'd get back with me when he had sourced a complete and functional FM Towns 20F PC. About a week after our first conversation he posted a video of the PC, Monitor, Keyboard, Mouse and Control Pad all connected and playing a game. He quoted me a price, I paid it without hesitation, he boxed it up and then I waited the interminable 2 weeks for it to arrive.
As is the case with almost every large item I buy from Japan, the shipping box was just demolished. The monitor had a tiny bit of cosmetic damage that might have been from the shipping. Otherwise everything arrived intact and seemed to work normally when I finished setting it up. The monitor was crisp and clear, the PC booted CDs without any fuss, the mouse, keyboard and joypad were all working normally. After my initial relief that it was all good, I noticed that unlike the video the seller posted, the CD access light and volume LEDs weren't lighting up when the system was working.
I posted about the problem on Assembler Games and possibly one other place hoping this was some common problem, but that never really went anywhere. At the time I tried to disassemble the PC to see if there was any obvious physical damage, but I couldn't get very far before I was stymied by an incredibly intricate system of interlocking panels.
Every couple of years my thoughts wander back to my FM Towns PC and how it's *almost* perfect, and I think about trying to fix those lights. And occasionally I would sit down with the PC and see if I could figure out how to get it apart without breaking it.
Thanks to a helpful reply on the FM Towns Facebook group, I was finally able to get over that hurdle and get the silly thing apart. The outer case is comprised of about 7 sections, each of which needs to be taken apart in a certain order. Some of the sections are held on with tension clips alone, others are a combination of tension clips and one or two cleverly hidden screws.
After wiggling, checking, finessing, popping, checking wiggling, unscrewing, checking wiggling etc... the FM Towns finally gave up its secrets.
The two most annoying parts were 1) getting the floppy drive cover off - there's a screw hidden under a panel on top which is somewhat obvious, but the piece's tension clips have a death grip and it doesn't want to come loose without considerable force - it just has to be pulled straight outward from the front and 2) the front CD and control panel is fastened by a screw hidden under the floppy drives. The floppy drives are only secured by the two tension clips which have to be pushed down while the drive is pulled out and forward, but the connector usually has such a good grip it almost feels like there's a screw back there. There are two tension clips over the CD door that you might be tempted to try pulling loose, but the front panel is actually screwed into the CD/control panel assembly so you have to get that whole module off before being able to remove front panel.
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| There are six screws on the back of the CD/control panel assembly, but only these two need to be removed. Then the front panel can be taken off by releasing the tension clips on the top. |
Once the CD/control panel module is safely detached, there are only two screws that need to be removed to get the front panel cover off. The rest of the screws on the yellow plastic piece are used to hold the CD drive assembly together.
The LED's not lighting were the source of much speculation and brainstorming. The two most likely causes were physical damage which occurred in shipping, or component failure.
What I found, 11 years later was this:
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| A ripped ribbon cable preventing the front panel LEDs from lighting. |
The next step in breaking things down was to remove that strip of black fabric tape. It's very old and sticks very well. Trying to just rip it off could result in further damage to one or both ribbon cables. The tape was heated with a hair drier to soften the adhesive and was very slowly and gently peeled off.
The LCD panel, just like the rest of the FM Towns was a bit of a puzzle to get detached. Fujitsu must have saved a TON of money not putting screws into things.
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| Another view of the torn ribbon cable |
Fortunately only the two conductors on the edge were damaged. I tested the third for continuity to make sure.
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| The insulation is scraped away from the damaged traces |
To repair this, I started by scraping away sections of insulation from the damaged traces.
Then a strip of Kapton tape was used across the back to hold it together and re-enforce the integrity of the rest of the ribbon.
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| A strip of Kapton tape is used to give the ribbon a little extra support and resist future tearing. It's not a miracle solution, but every little bit helps. |
Then a strip of Kapton tape was used across the back to hold it together and re-enforce the integrity of the rest of the ribbon.
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| 30AWG wires are soldered to the exposed ribbon, reconnecting the traces |
Two short lengths of 30AWG wire were soldered to the exposed conductors to repair the torn traces. The ribbon was gently flexed a couple of times to ensure the wire would bend without separating. Another strip of Kapton tape was placed over the other side to protect the patch. After testing conductivity, the LED and front control panel was re-attached.
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| The panel is reattached. |
After reinstalling the panel, one last continuity test was performed to ensure that the patch was still holding.
And what a beautiful sight to behold!
Even with the lights working now, I still suck at Rayxanber...
Hi. I just wanted to ask a question if you might be willing to reply to. I have an fm towns 20f in pristine condition but I have been looking for a compatible CRT monitor. I try to connect it to a regular desk top Dell monitor but it does not appear on the screen. When I connect the VGA plug to the Dell lcd it just gives me the message of no VGA connected. I can put a game and the cd drive works with no problems as I can here it playing based on the sound of internal speaker. My question is if you know if the fujitsu fm towns 20f is only compatible with the fujitsu monitor CRT from its time? Any inputs will be appreciated. I don't have any old CRT monitor to test it. I thought it was the cable plug but I bought a VGA cable to connected and the Dell monitor keeps giving me that prompt of no cable detected.
ReplyDeleteWell, to start with I'm not really an expert in FMT video, but I may know enough to help set you on the right path. There are two problems you need to solve. The FMT outputs RGB from a DB15 connector and AFAIK Dell did not make monitors with such an input so I assume you have some kind of DB15->DE15 adapter like this one: https://www.ebay.com/itm/352868121427 . Whatever adapter you're using, you'll want to make sure it's wired specifically for the FMT (There's a simple cheat sheet here: https://nfggames.com/forum2/index.php?topic=6657.0). It's dangerous to use adapters made for other PCs of the era (MSX/X68000) - I can't recall which but one of the manufacturers made the video output different enough that there were anecdotes on the now defunct Assemblergames forum of users claiming that they fried the video out on their Towns trying to use a VGA adapter made for the other computer platform. It is very important that you check the adapter is wired correctly - you should be able to do this with a multi-meter and that cheat sheet I linked above.
DeleteIf you're sure you have the right physical adapter and that all of the right pins are getting connected from the FMT to your monitor, it's possible the monitor you're using just isn't compatible with the video modes the FM Towns outputs. IIRC a lot of standard PC CRTs didn't support 24khz or some of the other odd video modes the FMT outputs. You might want to see if you can try a different monitor - like an NEC or something labeled "multi-sync". You might also want to consider getting an OSSC (https://videogameperfection.com/products/open-source-scan-converter/). It's a bit of an investment, but it's known to be compatible with the FM Towns video output modes (again, provided you have the right physical adapter) and will give you a lot of good options for using your FMT with monitors or TVs.
If you're still stuck I'm happy to have a discussion in the comments here. Alternatively you could reach out to the guy who runs townsworld.com, or join the "FM Towns Club" on Facebook (https://www.facebook.com/groups/298509760178487) and ask your questions there.