A Mysterious Japanese Mega Drive 

Thanks for watching. I picked up this poorly Japanese Mega Drive recently. Are these common mods? It will be going to a nice new home where it can be rehabilitated! :)

That Megadrive looks to be in great condition, a very nice little pickup. It's a great feeling when something that you've called as "don't work" makes a last minute turn around. Nice looking new place you've got there too, well done man ;)

I bought a Japanese Mega Drive at a flea market here in Italy a few years ago. Same model number as yours and it came with a strange RF cable sticking out from the machine as well. I presumed it must have been some grey market unit, imported before the official PAL machines were available in Europe.

Good to see that you got it working in the end. :) I can confirm that it was commonplace for shoddy grey importers in the UK to modify Japanese Mega Drive's by attaching a fixed RF lead. I remember one particular grey importer in 1989 warning potential customers that this is what their rivals were doing.

Oh my goodness, putting the cartridge in, switching on and seeing that Sega logo. Seems like yestday

Glad this show is back! Really like the laid back atmosphere. Place looks nice. Looking forward to see the cleaned up and restored Mega Drive

European scart cable with it's box is incompatible with the Japanese Megadrive, it's a matter of sync signal, you need to mod the cable too

This is a Japanese console that was modified to a Pal for the Chinese Hong Kong market done in massive batches and totally rushed apart from the cosmetics it is to intents and purposes A Pal machine

Wet common to do theRF mode on grey imports. I would of done hundreds myself in 1989

You are absolutely right about SE Asia. Last year my brother went to Thailand and came back with a PAL-modded JP MD for 700 Thai Baht (~$20 USD). It was the same “VA6” revision as yours but the PAL RF mod was done differently. I was able to reverse the mod while adding my own. :) There was a ceramic capacitor and crystal connected to the bottom of the Sony CXA1145P video encoder chip with their radial leads twisted together. They also connected the common terminal of a two-way switch to a VDP pin where they also severed a trace to disable the factory setting. The other terminals went to 5v (wire) or ground (jumper to RF modulator) for alternately pulling that VDP pin high or low. The switch itself was soldered to the side of the RF modulator with a tiny jumper to ground on the RF modulator. The RF modulator was solder-mounted to the ground plane extending off the left side of the board where there is empty space. This allowed an external cable to connect through a hole in the side instead of having a semi-permanent RF lead attached. There was also a notch cut for the switch. I removed the extra components, restored the traces, and gutted the RF modulator to restore 60hz NTSC. I restored another trace and repurposed the switch as a language select switch then cleaned up the notch. The hole from the RF modulator’s RCA jack is about to have a 9P mini-DIN installed for Sega Triple Bypass v2 (3BP), that way there are no pointless holes in the case. The last 3BP I installed replaced the original RF modulator on a late-VA6 Genesis but the JP MD wasn’t supposed to have one. Whoever put one in there for me gave me the perfect place to mount the mini-DIN. ;)

Grey importers sold lots of Japanese Mega Drives converted this way for PAL use - no idea who carried out the work for them bitd, pretty sure the official Asian PAL variant was a different mobo with a fixed RF replacing the EXT port?

The three big wires are there on any VA5/VA6 model 1 mega drive, regardless of region I believe. I'm not sure why they were needed but they even have silkscreen markings for where to put them so it's clear they were not an afterthought or temporary. I think but am not sure that the mods near the CPU are also original and not part of the PAL mod. I've seen a lot of examples of this PAL mod. I believe there was probably one company in Hong Kong or Taiwan making these and selling them all over the world. The Mega Drive undersold terribly in Japan, so it was probably pretty cheap to get Japanese mega drives and mod them. One thing that's kind of quirky with these PAL-modded JP mega drives is that they for whatever reason added a second crystal to supply the PAL chroma subcarrier to the encoder chip. This seems like something that they'd only do out of ignorance because you can also just change the main oscillator to the value used in the PAL version. However, it's possible those oscillators were not easy to come by. A consequence of this is that the frame rate is not quite the same as what a real PAL mega drive would be--it's off by a fraction or so.

This would have looked better in my bag of tat. its amazing how some peoples fixes are shockingly bad now. looking forward to more

This is an original Japan mega drive that was modded by sega in Japan to work in Hong Kong for their pal players. Japan mega drives don’t have an RF port or RF shielding.

OK, you just helped me prove sources incorrect about which JP Mega Drive consoles have the Trademark Security System (TMSS) boot screen. I’ve seen multiple places online saying that no Japanese consoles with “AV Intelligent Terminal / High Grade Multipurpose Use” printed on top are VA6 TMSS, but yours is. I was always doubtful of that claim because the board is the exact same as VA5 but with a different chip installed at IC4 with that chip (315-5433) adding TMSS and designating it VA6. There was no reason to tie that chip change to an external cosmetic change if they weren’t even going to change the silk screen on the main board. That’s right: VA6 was ready to go before VA5 shipped and every one has both designations silk screen printed right next to IC4’s footprint telling you that it is VA5 with one chip there (315-5402 ) and VA6 with another (315-5433). Clearly, the need for TMSS came up and it was developed alongside VA5. They probably had too many of the old non-TMSS 315-5402 VA5 chips produced or in production to throw them away and knew that they would be switching to the new TMSS 315-5433 VA6 chip with TMSS when they ran out of the old VA5 ones. Heck, they might’ve even started shipping both simultaneously since even a percentage of new consoles having TMSS would throw a wrench into unlicensed 3rd party game sales (the thing TMSS was intended to counteract). Before someone claims that it was board swapped by the modder: It would be one heck of a coincidence if that happened to both of us. Yes, my PAL-modded JP MD from Thailand is also VA6 TMSS and also has “AV Intelligent Terminal / High Grade Multipurpose Use” printed on top. Mine was found in Thailand with the Thai importer’s tamper seal intact so it definitely wasn’t swapped since it was modded for sale there. Turns out the “AV Intelligent Terminal / High Grade Multipurpose Use” text really is equivalent to the “High Definition Graphics” text on a Genesis console. Early VA6 Genesis consoles have “High Definition Graphics” printed on top and late VA6 Genesis consoles do not. If anything, finding out that the top markings are equivalent simplifies things.

I have this same model with the RF cable. It was brought from a retail store brand new many years ago. It wasn't until recently that I conclude that the RF cable was actually not part of the mega drive as it stopped working, so out of curiousity I opened the mega drive and saw this RF device that was not attached but loose in the console. I used a different method to connect to the TV using the S Video socket and the mega drive works fine but with better picture. The mega drive can run English games but the language is Japanese because it's Japanese of course but my point is I did not modify it. For example I have a English Streets of Rage game but it comes up as Bare Knuckle. I am thinking modifying with a switch to change language but need to look into it more before attempting.

I actually put a bid in for this last month but forgot about it. I see you got it for 12.50 so a nice bargain! The Japanese models obviously had no RF modulator as standard. Seems unusual that someone would go to the trouble of adding one instead of just using a Scart cable. Still, a lovely machine that just needs a good a clean and some TLC.

Its possible the mod required a trace cut somewhere? Never mind. Saw the end. Perhaps drown the power switch in contact cleaner?

Thank you. We got one in Ireland from the UK as kids and I just opened mine. It has an RF modulator loose inside and it's rusted. The wires are barely hanging on. Is it safe to cut them loose?

Dan, did you ever get this fixed or is it still on the shelf?

Hey man, do you ever restore the console? I think I bought one in the same kinda shape, only mine has a 50hz 60hz mod switch but it basically runs as a 50hz. No language mod but it plays in english. Has all the indicators that it is a japanese version though, not a pal asia model.

There is no metal shielding inside Japanese mega drives?

Hello 👋🏽 I have a question. Will a PAL mega drive 1 motherboard work on a Japanese model 1? If so, can it play Japanese games?

Great video. But this isn't a Japanese Mega Drive. It's the Asian version which was modded by Sega for Pal countries like Thailand or India.

Love seeing these weird grey market MDs. They're a really interesting bit of janky history.