SEGA NEPTUNE REPLICA FINISHED

Hi Everyone,

Thanks for coming back and checking on my blog. Some of you guys might have been following / found my blog because of my EPIC Neptune project I set myself a few years ago after seeing the awesome Longhorn Engineer's tutorial on creating a Neptune using a 32x and a Genesis / MD2.

My idea was to learn soldering by making one of my spare Megadrive 2's into a working Neptune. But rather than leave it there I was going to use the skills I'd picked up making designer toys to make a replica outer shell for the mod and create an actual Neptune.

Well my project started with the hunting out on ebay of a 32x and then getting as many Neptune Prototype shell photos as I could and comparing them with my MD2. I'm pretty much 100% convinced that the Neptune prototype shell is a modified Genesis 2 shell. The bottom certainly makes me thing this as the lower square pan is exactly the same as a Gen 2 shell.

I documented the process of making my Neptune replica shell at most stages of sculpting. I thought I would make a slideshow so you guys can see what the steps are to make a Megadrive/Genesis 2 shell into a Neptune shell.

To finish it off I back painted the perspex LED 'window', glossed the buttons and applied the waterslip decals for the logos so that it looks like the prototype photo's I've seen on the web.

I've placed a few photos on the page as well as making a gallery for you guys to look through.

As you can see from the above photo I've finished the internal modular setup of the Neptune for when I eventually get a 32x. I really wanted to make sure that I would not need to destroy the 32x to make the Neptune. I will simply just have to take the 32x apart, fold it under itself and plug it in. Well I'll actually have to desolder the choke and resolder it on its side to lower the profile of the edge of the 32x so it will fit in the Replica case.

Again I made a slideshow of the progress I made with the mod and if you've followed my blog you will have seen all or most of them.



And to finish this post off which is a little shorter than I thought it would be. Its more photo heavy as I've basically posted most of my progress as I've gone along. I also made a Youtube video showing the shell and the internal mod.



Hopefully you guys like my replica Neptune shell. I'm so happy that its all finished off, and when I get a 32x I'll make it even more finished off. :-)

Catch you guys later on.

Porl''

NEW YEAR AND SOME NEW PROJECTS

Hi All,

A bit of a late Happy New Year! but there you go. :-)

I've been quiet again on the old blog front, the time keeps flying by which is a little worrying when you think about it. Over christmas I don't get much time to do many geeky projects as we're out busking with the kids Brass band that me and my wife volunteer for. Always good fun getting out there and playing the classic christmas tunes!

Well its a new year and I want to get cracking with a couple of Sega based projects and 1 arcade game project.

Currently the 2 Sega projects are on the go which I will no doubt make a post about when they are all done and finished. I'm just waiting on an ebay purchase to finish the larger of the two projects wiring then I will be onto the final touches for it. I'm really pleased with it so far, mysterious huh? :-P

I also have an arcade game project which I made a quick video intro for which is at the bottom of this post.

While I was working on one of the Sega projects I was watching some of the arcade and retro console repair videos that I subscribe to on YouTube and I started getting the urge to have another go at repairing an arcade game.

So off I trotted to one of the arcade forums I go on and snagged myself a board with some issues. Mainly this games problems are in the sound department. The game is WF SuperStars :-D I used to play this loads at Mr Man's video shop on Rosliston Road when I was a teen so its got a great nostalgic feeling for me.

Its going to be fun to tackle issues in the sound area of a Jamma board as I've not poked around those areas yet.



BUT, I need to get some of these other projects finished first before tackling WF. :-P

So catch you guys on the next post which will hopefully be a nice completed projects post.

Porl''

ARCADE MACHINE REFURBISHMENT - RESURRECTION PART 5. MARQUEE AND JAMMADRIVE 2

Hi All,

Well, the weekend has passed and I managed to get a little bit of work done on the arcade machine while my fiance was planting trees with her mom in one of the fields. Shirking a little bit of manual labour I slinked off to my arcade machine to continue work.

My main aim for the weekends work was to try and figure out the marquee light and try to get that hooked up and working. I must admit though I hadn't got a clue how the thing hooked up to the power supply as it was just 2 wires and they weren't standard colourings to the wires. Hmm, surely one has to be ground and one live? There's a sticker on what looks like the ignitor? power block for the light that says 240v so I thought 'brilliant! I'll hook it up to a mains plug and see what happens'. Well, what happened was the bulb got really bright then a burning spot appeared at a part of the bulb and it switched off. Doh!! Burnt it out and my confidence with getting that thing working dropped through the floor.

I could try to get another bulb to fit but I might struggle and then it could just burn out like this one did because its not wired correctly, so I decided to head down to my local B&Q diy store and pick up some tree ties for Roz and her mom and picked up a small strip light while I was at it. While I was there I checked over all the lights and checked that the one I got was mains powered so I could just hook it up and I'd be away.

I had a good long piece of mains cabling and scrounged a plug and hooked up the light to check that it fired up and worked okay. And, bingo! It worked! Next step is to get it mounted to the marquee board and check again. Here you can see it mounted to the board before I routed the wiring down the back trunking of the machine and down to the power strip thats sitting in the base.

After I got it all cable tied to place and hidden in the trunking I go it switched on in its new home. :D

Check that glow! haha. Another tick on my list of things to do there. Marquee light, done!

Here's how the machine looks at the minute with the glass and marquee sign all back in place.

Looking pretty snazzy I think. I don't know what it is but when the light turned on it just clicked to me. This is finally an arcade machine, it just feels more right.

During the week I'd received some new Neo Geo MVS games so I thought I'd bring one of the cartridges with me to 'test' out in the cabinet. Metal Slug 2! :D

Its crazy how different the game looks compared to my little LCD TV I've got at home. Standing up close to the CRT monitor with the scan lines etc makes it feel a lot more proper.

I got a nice little stash of games and I'm really itching to complete them all but the one thing I'm making sure I don't do is credit my way through them. I.e. just pressing the credit button continuously to force my way through the games. One thing I've been doing with Metal Slug 2 is giving myself 3 credits and 3 credits only. Trying to recreate only having so much change in my pocket like when I was a kid. Man, is Metal Slug 2 a hard game though!! I can only get to the end of level 3 so far with my 3 credits. Its crazy tough even on level 4 difficulty settings. I'll get there though.

The Games I got (as I got side-tracked there) are : Metal Slug 2 (loose cart), Metal Slug 4 (full kit), King of Fighters 2001 (loose cart), Puzzle Bobble (loose cart) and Tecmo Soccer '96 (loose cart). I'll probably be selling on Tecmo Soccer as Im not that into football games but the others are definate keepers.

So that was Saturday's work and I thought I would be all done for the weekend but we headed back on the Sunday so Roz could help her mom out with some more tree's so I had an idea of what I could leave in the machine semi-perminantly as I don't want to be leaving my 'real' arcade boards in the machine when it's not at my house yet.

So I used the time in the morning at home to source out an old Megadrive / Mega CD base plate from my wardrobe to see if I could modify it into a PCB stand for my Sega Jammadrive 2 :-)

I found the base plate out but quickly found out that its not going to fit the Jammadrive 2 unless I take the rubber feet off the bottom of the casing (not gonna happen as I want it to look stock :P ) or modify the plate. So I got my metal saw out and started hacking away at the base. I got a little way but needed some proper equipment so I took it to the farm and used the saws there.

Here you can see the Jammadrive 2 next to where I was working so I could keep offering up the plate to it to see how it was fitting.

Right, a little disclaimer...I'm not going to show the finished off plate because its VERY embarrassing and looks like a torture device from Vlad the Impaler (and it actually did impale me at one point and cut my hand doh!) but it does fit nicely and work very well. I drilled out some holes and mounted PCB feet that I had spare so that I could then screw that into the internal wooden wall of the arcade machine.

And here is the Jammadrive 2 sitting in place on the wooden wall. The way I positioned it is so the weight of the console pushes downwards onto the mounts of the base plate so it will keep in place and it also has the Jamma edge at a nice easy to access position. I've also mounted it quite high on the board so that I can still fit other arcade games in there past it so I don't have to take it out all the time to put other game boards in.

Im really pleased with how it sits in the cabinet I must admit and really happy that the baseplate worked after all my hacking of it (and my hand).

And here you can see the machine running Streets of Rage from the Sega Mega Games 6 cartridge. A neat little fact about this cart is that it has the full version of Streets of Rage on it so much that if you flick it over to Japanese language you get the game Bare Knuckle instead of Streets of Rage :D A good cart to test your language switch mods on ;-)

I thought I could leave this cart in the machine and there are a few games to have a blast on when there aren't any arcade boards plugged in.

Also its inspired me to dig some of my megadrive arcade converstions out of my shelves such as golden axe and I know its not technically an arcade game but its pretty close to the original, Splatterhouse 2.

Oh, I also painted up the old coin door that I mentioned in one or two of the video progress reports. Well it turns out after I painted it up that it didn't fit and wasn't the correct door!! Double dang it!

But I scratted around and found the proper one which is chrome and only needed a quick brush down to look half decent again. I mounted it into place and quickly tie-wrapped my Test Button to it but I'm going to extend the wiring on that so that its neater when you open the door.

And that's the progress so far. I'll leave you until the next post.

Catch you later

Porl''

SEGA DREAMCAST INTERNAL VGA MOD

Howdy!!!

Man I must be back into the blog posting big time haha! So many posts in one week!

Anyway, this morning I made a very quick video showing the Dreamcast I modded the other month. I'd been meaning to post about how I did it but thought this morning that I would make a quick video instead and show it working etc.

Its a bit of a rambling video as I did it as soon as I woke up this morning so excuse the stupid throat clearing. I was still drinking my morning cup of tea so I wasn't fully up and running yet haha.



I recommend trying this mod out if your thinking of running it on a monitor and don't want to splash out the cash for the VGA cables. The components really are so much cheaper. And use the Kynar wire that Mmmoneky uses as you will get the tight case to fit back together a lot easier. :-)

Catch you later

Porl''

PC ENGINE RGB MOD

Yes!! After looking longingly and lovingly at pictures of the awesome and mysterious little white PC Engine in Computer & Video Games, Mean Machines and Game Master magazine as a kid I finally own one! And I tell you what, its a thing of beauty! Sounds stupid to say but it really is! It's well known for being the smallest games console in the world (well, it was) and it really is tiny, and pretty much perfectly formed. Its footprint is the same as a CD case. If you have one to hand check it out then imagine that case being about an inch thick and you have the size of it. TINY!!

I've always wanted to have an original white PC Engine. To be honest I'd love to have a grey Core but the white has always been embedded in my memory as the one to have from being a kid. When I check ebay I more often than not check out PC Engines but have always been put off with the prices but one day I spotted this little fella on there listed as faulty and feeling confident I could fix it I bid and got it at a steal! £12!!! TWELVE POUNDS!

It was listed as faulty and I was really really hoping that it was just down to the owner not knowing that Japanese RF doesn't work properly on UK tv's. If it shows a signal it'll be really crap and wibbly etc. And I was planning on doing the RGB mod on it to get it to run through scart anyway so that wasn't going to be a problem.

The day came and the little fella turned up and jeez was I impressed with it! Its pretty much perfectly formed and covered in little details. I love the indented call-outs for whats-what on the case. Detail you don't see at all really on other consoles, if things are named they are printed on not moulded.

The case hasn't yellowed at all and is in great condition. The only problem....I have no game to check that it works! I was really hoping that the machine would at least tune a single coloured screen onto the tv but that wasn't to be. I'd need a game and a pad anyway as I got it as just the console so I got back on the 'bay and routed out a game that should be good fun to test it out.

A quick bid and win on a nice looking white pad and a game and we're away! I don't think you could go very wrong with getting a Capcom game to test a console out with, especially when its a Street Fighter 2 game and its got all the bits and bobs that go with it, check out all the cool stuff that comes with the PC Engine version of Street Fighter 2' Champion Edition. :-D

If you don't know much about the PC Engine's then you may be wondering where the game is in that photo, well its a card based system, much like the original Sega master system (although the MS uses cartridges as well). It's quite weird when your used to cartridge games but it adds to the charm of the machine and makes it all that little bit different to a megadrive or snes.

So, now I have everything to test the console out I excitedly plugged it all in with an rf cable borrowed from my Snes and finally managed to tune in an image. It works! No repairing needed! :-D The image is crap! But it shows the console works and is going to be a viable candiate for a nice rgb mod.

I'll again be following the brilliant guide on Mmmonkey's website so you can follow his guide there on how to do the mod, I'll just post up the photos of my progress and note down anything I encountered when doing my mod.

The guide to follow can be found here : MMMONKEY PC ENGINE RGB MOD

First things first I opened up the case and had a good nose around the insides and located the offending RF unit that's to be removed.

There he is, the mottled aged looking unit. He needs to be desoldered and a little area next to the hole for the connector needs scratching back to bare metal for soldering too.

 Mmmonkey has a really nice and clean way of doing his mods and I tried to follow the way he mounted the Din socket as close as I could. Once soldered on the unit is solid and I don't think It will get wiggled loose from a lot of use as it might do if glue gunned on there. I highly recommend getting your hands on a fibreglass pencil from ebay (other online vendors are available haha) as it takes a little while but you will get a really nice and clean metal area to work on from using one. I would have hated to just scratch the green areas away with the scalpel.

So once your little socket is in place you start soldering and routing the wiring from the card reader area (underside of PCB) to your socket. Again following the guide from mmmonkey you shouldn't go wrong. I would recommend writing / doodling it down on a piece of paper though so it gets in to your head, well this is how I do it otherwise I make daft mistakes and loose the orientation of the socket / pins.

You want to keep the wiring as flat to the bottom of the board as you can so that it will sit level again in the case.

In the above photos you can see that I've used electrical tape to help support the wiring along the length of the pcb. This should help to keep the wiring nice and tight against the board as well as hopefully stop and tugging on the wires which could pull them away from the solder points. I used some green electrical tape in an attempt to make it blend in a little :-P also, I would normally recommend using a glue gun to keep the wires in place but I think the spacing under the board is a little tight so tape is a lot lower profile.

Mmmmonkey recommend using a small din socket that is similar in size to the controller port on the pc engine, I couldn't find one that was the same pin configuration but I found one that matches the Sega Megadrive 2 A/V port so went with that instead. So if you struggle to find one that matches the controller port go for the Megadrive 2 Din socket instead. :-)

And it fits in the case nicely without having to make the hole in the case any bigger.

I don't have any photos of the cable being made but again, I just followed the mmmonkey guide. As long as you keep the orientation of the pins the right way round you wont go wrong. Unlike me who while being tired didn't notice I'd turned the plug slightly and couldn't see where I'd gone wrong. So make sure you have the notch on the pin holder the right way round and you'll be sorted.

Here is the finished PC Engine with the scart lead. A fully working Japanese PC Engine...finally I own one!!! :D

And it looks 'proper' not like the ones I've seen where they just have the scart lead perminantly coming out the side of the case.

Here is how it looks now on my TV, perfect :D some scan lines would be nice but for being on a modern telly I think it looks great!

So I guess in closing. If your after an original white japanese PC Engine but are unsure if it will work over here I'd say get one and do this rgb mod to it. But thats if your confident with a soldering iron and aren't to worried about getting in the case and wiring to the pcb. If your not that confident I would say go for one of the grey Core grafx pc engines which look awesome as well but also have the rgb output (I think).

They are awesome little machines with some amazing games on them as well as looking the bee's knee's in the casing department!

Thanks to Mmmonkey for his awesome website and guides and I can't recommend his website enough! :D

Catch you later

Porl''

JAMMA SEGA MEGADRIVE 2 : PART FOUR

Howdy y'all,

It's been a little while since I posted last about a geeky project. Basically I've been caught up over the last few months with house / garden improvements as well as doing an RGB mod to the PC Engine I purchased from ebay a while ago. I was having a really hard time for some reason with getting the mod to work and finally got it figured out. Basically the best tip I can give is draw down the wiring locations your going to use and you do use on a piece of paper as you go. I didn't and kept mixing my wiring up like a dope.

Anyway, I've been of on whats commonly called a "Stay-cation" this last week and chose to use some of my holiday at home to finish up some retro projects I had on the go as well as play some games etc. The main project I wanted to finish was the Jamma-drive 2, which is what I did.

With the controls being finished in Part Three all I needed to do was possibly overclock the processor to a switchable 10mhz and finish off the casing. Tidy it up and paint it, then using printable water-slip decal paper make a decal for the casing.

After having a good play on the Jamma-drive2 I decided I was going to have a go at overclocking the processor, shouldn't take too long seen's I've done it before. I set about making my crystal circuit and then started the process of heating pin 15 and with the pick tool, slowly pull the leg out from underneath the processor. The legs on the processors for the megadrive 2 are curled underneath it to slightly raise it from the pcb, I guess for giving it some cooling. Anyway, I dont think I had the soldering iron hot enough and pulled the solder pad up with the leg of the processor!!! The scariest possibility happened!! Man I was cross with myself. This is the reason that not main people overclock the model 2's, its way easier to just cut the leg of the model 1 and work on that rather than threading the needle of the model 2. So, with the solder pad now pulled from the board and stuck to the leg what do I do? I try to take clean the leg up and get the solder pad off it and the leg has taken too much wiggling and snapped off! PERFECT!! >:-( Screwed processor city!

I put everything away and took the pup out for a walk to try to get away from the ruin I'd just created, I'd spent all this time making a Jamma-drive and then balls-ed it up overclocking it! Gah!

After an hour we got home and I started trying to see if I could fix it. Out came the pick tool again and I scratched away some of the plastic around the broken leg to expose some of the broken leg and got a little wire soldered onto it. From a video that has been taken off youtube I remembered something about a guy soldering to a point on the board next to a printed 10. So with a "what the hell!" mentality I soldered the wire into the "10" location and went to see if it would work. And what do you know? I blumin' fixed it! :-D

So lesson learned, don't get cocky when trying to lift leg 15 when overclocking and if you do end up snapping the leg off or pulling the solder pad from the board, you can wire to location 10 that is just below the processor. This has fixed the megadrive and its clocked as standard 7mhz. I think I'll probably attempt to overclock it now I know its working but I think It's going to stay at 7mhz so I can play it for a while :-)

Here you can see location 10 that I wired too. I don't have a photo of the wire from the processor to it but you can see it in the video below. You wire from the processor leg into 10 to make the link work.

Now that the thing actually works again (Phew!!) I set about finishing the rest of the project.

I stripped the Jamma-drive 2 out of the case and started finishing up the new expansion port. Sanding it and trying to get it as flat and blended as I could.

Here you can see the milliput holding the expansion port to the case and hopefully see it smoothed into the original case so that once painted it should look pretty stock.

Next step is to masking tape the little spongey feet of the case so that they don't get caked in paint as well as the sticker telling you what serial number etc your megadrive is. Then it's off to the painting stage.

I gave the case a quick coating of grey primer over the new expansion port area and then painted the whole of it with Halfords Matt Black car paint. I've found that it gives a finish that is very close to the way the plastic looks on the original Megadrive's. So once its dried it will get a coating of a Matt Varnish so that it keeps its plasticy look rather than being all glossy. In the photos it looks glossy but that is because its still drying. You might also have spotted the Neptune case having another coating of paint. I did a bit more work on it on my holiday but that is for another post ;-)

So, The case has been painted and now is dry. So, what does it look like?!

Pretty good to me, I know it could be a little smoother but to be honest this project has been taking too long, so it gets a tick from me. And in certain lights, as you'll see in the video, you can't really see the join. :-) Overall Im really please with the look of the expansion port. Especially with how sturdy it is, It has no wobble or flimsy-ness to it.

And here is how the hot glue and milliput is covered inside the case. you can see the kind of "welding" I did with it to fix the new expansion port in place. And its solid, doesn't feel at all like it will crack or break.

Time to put it all back together again and get the switches set into place.

And here's how the case and new side expansion looks with everything all built back inside the casing.

 
Looks pretty sweet I think !!! :-D Im very happy with how it's fitted together, and when its sitting on the table you wouldn't even think there was anything going on underneath the case. A real Street-Sleeper :-D

So, for the finishing touch to this little project. I want it to look stock but I also want it to still show a little hint as to what it is. To achieve this I bought some water-slip decal paper from the internet so that I can make my own "Jamma-drive 2" logo to replace the megadrive 2 logo thats already on the case. To start I measured up the height of the existing logo and got onto illustrator, and with a Sega typeface I layed up my logo. Logo all made to size and its onto the printer to get the water-slip decal printed out. Once its printed you have to spray some Matt Varnish onto the decal to make it waterproof and then onto dunking it in warm water.

And with a little bit of wiggling here is what the finished decal looks like on the case with a megadrive 2 underneath for comparison. :-)

Im super happy with how the whole project turned out. I don't think the case could have come out any better, the waterslip decal really puts the cherry on the cake as it would make you look over the jamma-drive and think its standard but make you do a double take and go "what!?!"

And here are 2 videos I made of the Jamma-drive 2. The first video showing you the insides of the Jamma-drive2, including the overclock repair.



Here is the second part which show's the Jamma-drive 2 playing some games. :-D



Man I'm happy this project is finished now as it was meant to be a nice quick and easy one, but with the RGB problem and then having to figure out the controller pads it dragged on a bit. But the finished 'drive has come out great I think.

Catch you all later guys

Porl''

JAMMA SEGA MEGADRIVE 2 : PART THREE

Hi everyone and Happy New Year! :D

I hope you've all had a great chistmas and new year holiday.

Rightio I've just about finished my Jamma-megadrive 2 and thought I'd post up the next part of my build. This post is about the trickiest part of the build, hacking up the pad and getting it all wired up to work with the Jamma fingerboard and through that, your arcade stick.

I found that when I tried doing google searches about the pad-hacks all I could find were guides / pin-outs for the Megadrive 1 joypad. I wanted to use some Megadrive 2 pads as I had a few of those and with them being newer pads they should last longer. Should be easy enough to match up the guides with the MD2 pads, they can't be that different right?....wrong!!! They seem to have changed the PCB layouts and possibly manufacturers through the years. With the wiring switched around and not very well marked out.

Undetered I opened up one of the spare MD2 pads and got desoldering the cable from it so that I was left with just the pcb. Then comparing up the pinouts hopefully got the solder points matched and started soldering wire after wire to the megadrive pad, the fingerboard and to the joypad solder points on the Megadrive 2 pcb.

Rush off to test and hey, the controls work in a fashion! ... up is left, left is down, start works and only B does anything. Bugger! That didn't work then.

I decided to dig out my MD1 pads and check out the pcb's inside them and see if they match up with the pin-outs from google. Well, only 1 of them did. I guess that during the MD1's life they changed the pads manufacturer and/or design.

With the pad that matched up I desoldered and re-wired the pad to the Megadrives joypad solder pads and to the fingerboard points marked out on my Supergun wiring guide.

I was really hoping that I would do the wiring a lot neater than it is in the photo. The wiring is like a rats nest because of me having problems with the original pad. As you can see I wrote wiring numbers 
onto the pad so that I could easily match up the points to the solder pads on the joypad connector. You can see that I've wired from the non-ground side of the button area to the jamma edge connector. This sends the signal from your arcade joystick through the game pad which then gets transmitted to the Megadrive which then tells the games what the hecks going on :-P. To get the ground from the pad to the Jamma fingerboard you scrap away some of the green colouring to get the bare copper and solder a wire from there to a ground on the finger board. 9 wires from the fingerboard to the pad and 9 wires from the pad to the Megadrive 2.

Bingo! This pad worked straight away! Up, down, left, right all work! A,B,C, Start all work too! :-D

Onto the next pad...

I couldn't find another pad in my collection that matched the working MD1 pad so I checked my non-sega 6-button pads and found this one which had auto fire and slow-mo. I wouldn't be needed those as I wouldn't really be able to set them up easily enough on my arcade joystick. So I just soldered it as a normal sega 3-button pad. Thankfully the top left wiring points were numbered which made it easy to match up again.

And this time I routed the wiring a lot neater :-P I wish I'd done it this way with the first pad but as it works and its for me I will keep it as is for now. Again you can see the wires soldered to the input side of the button area rather than the common ground side. These are soldered to the fingerboard.

And here is the underside of the Megadrive 2 joypad socket area.

Again you can see that its routed a lot neater. Also, I found that if you soldered directly to the pins for the connector then the arcade stick completely took over the controls and you couldn't plug a standard MD pad in the port anymore and get it to work. So, to keep it so the Megadrive2 could still be used with pads you have to solder to the little solder points along the traces rather than the pins.

Bingo bango 2 working pads, and with a little wiggling the Megadrive 2 still sits in the case. Player 1's pad is underneath the main board sitting inbetween the mounting points and Player 2's pad sits on top of the Megadrive2.

Unfortunetly I didn't get a photo of the final joypad layout. I'll update the post when I get onto overclocking the Jamma-drive 2.

Which is the next step. Overclocking and finishing off the case mod. It needs a little bit more milliput to smooth the joins and then giving it a blast with some matt black spray paint.

Catch you later

Porl''

JAMMA SEGA MEGADRIVE 2 : PART TWO

Howdy pardnurs,

Well now that the Jamma fingerboard is securely attached to the Megadrive 2's PCB and it fits into the case with its new expansion port we'll move onto the wiring. Through the whole process I will keep dibbing away at finishing up the expansion port as I'm using milliput and it takes over night to cure really. So I add little bits here and there and allow them to cure without the chance of me poking them...cus I'll be asleep :-P

To start with I found a few guides on how to make Sega Megadrives into Jamma-drives and all had a similar starting process:
1) Tap the RGB, sync and ground from either the RGB encoder chip or the additional solder pads on the A/V connector under the PCB.
2) Tap the audio from the solder pad under the A/V connector.
3) Plug the Megadrive into the arcade machine / or Supergun's jamma harness with the normal Megadrive PSU and check that video and audio are working okay.

This allows you to problem solve any issues as you haven't made that many connections so far.

Seem's easy enough right. A few wires and your away. Well, thats kind of right.

I decided to solder directly to the RGB encoder chip as some people said that this may provide a stronger RGB signal. I googled the chip in my V01 megadrive 2 and found the pin-out and started trimming and tinning wires and soldering the sucker up.

Well what do you know?! I get picture!! But, the image seems to move, kind of clicks from one point to another and back again. Like its switching between either PAL / NTSC or aspect ratio. Also the biggest problem, there is horizontal bluring through the colours. Really distracting and causing weird colour clashes. Bugger!

The wiring is so simple where could the problem be?! I assumed that my soldering wasn't neat enough and i'd either bridged two of the suface mount points of the chip so I checked them out and they seemed fine. Hmmm. I unsoldered the wires and then looked up the A/V pinout for the port and wired to the solder pads underneath it. Maybe you can't wire to the chip?

I go upstairs and test and darn it! The same problem! This is frustrating!

I got a few more pinouts and did some google searches and couldn't find anything on the problem. Then it occured to me that its essentially the same as doing an RGB cable so maybe I need to add the 75ohm resistors and the 220uf capacitors?

I made up a little Vero board with the resistors and capacitors and wired it up to check. Same problem only this time its a little darker now as the resistors are lowering some of the signal strength. Stupid horizontal RGB blur!! Its a little harder to see in the Zombies photo but that mottling on the circles is caused by the blur and shouldn't be there.

Thinking that maybe the RGB encoder chip might be at fault I decided to make up an RGB Cable for the Megadrive 2. I'd been planning on doing one anyway and had the parts so I got soldering. Using the great guide from mmmonkey.co.uk.

Another test but with the Megadrive 2 hooked up as normal (no jamma) and the new RGB cable and BING, picture is perfect. Nice and sharp with bright colours. Awesome for the cable as that will be used on my other Megadrive 2 and Neptune but bugger because it shows that something is still up with the Jamma wiring.

Looking over the wiring guide for the RGB cable I noticed that its got Composite Video hooked up via the scart but no Sync. Comparing that with the Supergun wiring guide I noticed that the sync pin on the jamma board is hooked up via the Composite Video pin on the Superguns Scart port. Could it be that?!

I found the composite video solder pad on the A/V port area of the Megadrive 2 and moved my sync wire over to there. A quick test and WOOP! The video is perfect!! No horizontal blurring and everything looking like its using the RGB scart cable!

I know, it seems like such a simple and stupid problem to have with the A/V but when everyone says follow the Encoder pin-out and hook up the RGB Sync and Video ground as is rather than using Composite Video out for sync then your going to run into problems. This took me a week and a half of headscratching and fruitless searching to figure out haha. Yes Im that tentative with hooking wires up incase I blow something.

Now that the Video is sorted I hooked up the Mono Audio out from the A/V port area to the Jamma finger board and hooked the Audio ground up to the Jamma fingerboards ground. Thankfully this worked straight away and is super loud through my arcade speaker, so loud i might have to put a volume switch on haha.

Here you can see my testing setup with Zombies (ate my neighbours) running on the Jamma-drive 2 with the audio hooked up. Thank goodness that stage one is figured out!

The next step is to hook up two switches, one for the 50/60mhz PAL/NTSC mod and the other for the English / Japanese language mod. I followed the guide from mmmonkey.co.uk again as I've used this mod on my other Megadrive 2 and it worked a treat!

My aim for doing this project was to try and keep my wiring as neat as I could. This is a problem though when your trouble shooting and having to hack up wires for testing. Its still fairly neat and easy to follow though.

Here you can see the points I soldered the wires too for the language and PAL/NTSC mods.

Pretty neat wire routing for me I think :-) and with this mod the hot glue is definetly needed as the points your soldering too are very small and you don't get much solder on there and its very easy to pull and break traces if the wires get snagged or pulled.

And here is my wiring up for the A/V parts of this project. I used some ribbon cable from an old DVD player to try and keep them more neat but the problem solving caused me to seperate the wires out doh. Still, its not too un-tidy I don't think.

Here is the view of the top of the Jamma fingerboard with the Red, Blue, Video ground and Mono Audio wired up. Actually looking again it looks pretty neat still. Once I've completed it the wires will be hot glued into place on the PCB and hopefully routed away from the voltage regulators heatsink as I think that might start to melt the wire casings if used for a long time.

And here you can see the underside of the Jamma-drive 2 with the wiring going to the solder points of the A/V port. Still not too messy and once I'm properly happy they will be hot glued into place to make sure they don't come pulled or anything. :-)

The orange wires are the power lines to the underside of the voltage regulator which are supplying the Megadrive 2 with +5v from the Supergun's arcade power supply so I no longer need to hook it up using the Sega power supply. The Jamma-drive 2 is now A/V and PSU cable free! :-D

Next up is hooking up the first joypad so that I can use my arcade sticks via the Supergun rather than a pad out of the front of the Megadrive.

Catch you later

Porl''