DreamBox - bacteria's DreamCast project

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bacteria
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DreamBox - bacteria's DreamCast project

Post by bacteria » Mon Jul 27, 2009 3:23 pm

Ran a vote on ModRetro for the next system they wanted me to portablize - 2nd place was GameCube with 23 votes, but DreamCast got 24 votes.

Here therefore is my work log so far:


Spent 1 hour to get everything disassembled. Join me on this WIP journey...

Initially, I thought, "crikey, this looks more complex", but by the end of it thought "meh, it's fine".

Ok:

DreamCast

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Cover off, only 4 screws to remove, and the "expansion module"

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Removed the power regulator and unplugged the controller plug board to remove it.

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Unplug the CD drive by lifting off.

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This then allows access to the remaining screws to remove the motherboard.

The thick CD drive, can be easily half thickness. It's just a board and the usual motors. Cut off the clear plastic strip off the back so you can lift off the CD mechanism and board from the metal plates (after removing screws).

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There, that's better!!

Here are the boards then, disconnected:

Left to right: power regulator, CD mechanism and board, main board, (above it) the board to the game controllers.

The two chips on the board need heatsinks, as they had some gunk connecting them to the metal shielding plates.

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There are a few plugs that I need to rewire to, then test the system works ok, then check the voltages and see what I can rig up.

Get this - the motherboard, with a little grounding removed, FITS IN MY CASE! :D

This project should fit ok in my case, the only issue is powering it. Cross that bridge when I get to it. Probably need Li-Po's this time!!

Not bad for an hour's work (I work quickly).
Last edited by bacteria on Fri Sep 11, 2009 7:32 am, edited 1 time in total.
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Re: IntoDream - bacteria's DreamCast project

Post by dragonhead » Mon Jul 27, 2009 3:52 pm

lipo and a picopsu

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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Tue Jul 28, 2009 9:53 am

Nah - Li-ion and no PicoPSU:

Here's a turn-up guys - my tinkering worked....

I got the Dreamcast to work properly and run through the intro of Quake 3 off one cell - 7.8v!

I gingerly checked on the DreamCast with the AC circuit, one pin gave 3.4v, one 5.08v and the other about 13.2v.

Removed the circuit entirely, wired up a Li-ion I had, not on full charge, ran about 7.8v; wired that to the 12v line, used a 7805 to the 5v line and a TI card at 3.25v (thought that might be good enough!).

What do you know - it worked fine!!

So much for needing 12v and so much for needing a PicoPSU!

Also, before, I just had a metal strip over the two hot chips; didn't conduct properly but figured I would put in a couple of heatsinks anyway; with the AC circuit converter, half way through loading the Quake 3 disk to get to the demo the system reset - with 7.8v it carried on to the intro video where Serge fires his guns! That means the chips are also generating less heat too!

Pic isn't great, reflection from the screen, but you can make out Serge's face on the screen.

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I only connected the screen to composite to test all was fine, will do RGB of course.
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Re: IntoDream - bacteria's DreamCast project

Post by underclocked » Tue Jul 28, 2009 8:01 pm

Your portables keep getting better! Can't wait to see this completed!

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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Wed Jul 29, 2009 2:13 am

Thanks! This DC project will be quite a mile-stone if I can pull it off. 3 months or so ago I would not have had the skills to stand much of a chance on this project.

One of the issues with having WIP threads on two sites is that you get different comments between sites - daftmike and others have put in some great input on this project, on the ModRetro site IntoDream link which you might be interested in seeing (page 3).
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Re: IntoDream - bacteria's DreamCast project

Post by underclocked » Thu Jul 30, 2009 8:08 am

Seems like you guys have(or will have) all this stuff figured out! Now that I have income I may use your WIP to complete a DCp someday. :wink:

Keep up the great work Bacteria!

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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Thu Jul 30, 2009 10:50 am

Thanks!

Assuming I don't fry both DC consoles I have, yes, expect a full WIP guide on this project. Check this thread and the ModRetro one as different posters add different useful information.
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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Sun Aug 02, 2009 5:11 am

Previous update - forgot to up it here too:

Cut off the side plate off the metal on the DC drive base, steel, so was quite tough.

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Using a fan on the heatsinks to keep everything cool. This is one designed as a PCI fan for a computer - salvaged from my first N64 system!

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The fan is a good one, better than is needed for this project, but keeps it all nice and cool!

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Here is problem number one - the overall thickness. 65mm at the moment, which means the final system would be 85mm thick (enclosed CD). Have to get this down, even if only down to 75mm!

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Anyway, ran the system for about 10-15 mins as in gameplay not logo screens; air from fan slightly warm but barely so, everything works fine. Admittingly, the screen isn't connected to the battery as well yet, will be.

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Composite looks nice, RGB will be better still!

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Problem number two - I am used to playing Quake 3 with the cursor keys on a keyboard to move and mouse for elevation and firing. On the Dreamcast, it uses the rather sensitive joystick for all direction movement, two of the buttons for strafe, one for moving forward, shoulder button for fire. Really wierd, had trouble trying to control it!

I think playing this game on the proper DC controller sucks compared to the precision from a computer keyboard and mouse combo, i'm either going to have to get used to it or make the portable purely designed for this one game; eg replace the joystick with buttons instead, etc.

I'm a bit concerned about the thickness of the system; and the weight too - the DC is far from light, and that's before you even add batteries!

If the portable is made double length, then the system can be half as thick roughly, however, double size would be too big, also had two plastic containers totalling 90mm thick, holdable but not overly comfortable; 70mm or so is fine, so the sides can be sloped/stepped. Mulling over ideas at the moment. Might also reduce the height more if I can so something about the fan (ie smaller one). Lots to work out...


Update:

Heatsinks get warm quickly, tried just having a fan blowing in the general direction of the heatsinks instead of using the PC blower unit, after about 7 minutes the screen started to get flash lines over it, chips must have been getting just a bit too hot.

So compromise - less height and same principle of a PC blower (as I used before) - home made version, made from cardboard and Blu-tac. The Blu-tac is easy to remove, not going to harm anything if removed, yet forms an airtight seal (reason to use it) as it is just weak putty. Fan is hot glued to the card. The fan will not be in the way of anything and away from the DC's drive unit. The card sits right on top of the two chips and heatsinks, the fan blows air in, out past both chips and out the other side (exhaust). This saves me about 10mm from the system height already. Tested it, a very good airflow indeed!

Before (BTW, the hole in the left heatsink was from a while back, however as the original gunk used on the DC to connect to the metal plate was only about 50% coverage, should be no issue with a hole in the heatsink).

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Blu-tac pressed into place

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Done.

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Ran it for nearly 10 minutes, fine, no issues; although the 7805 was rather hot! I might well put a TI card there instead of a 7805 as it will be cool and also (as I was reading recently) will help to prolong the life of the batteries because of the way it works.
Last edited by bacteria on Sun Aug 02, 2009 7:31 am, edited 1 time in total.
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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Sun Aug 02, 2009 7:30 am

Here's something interesting, people have said the DC motherboard is multi-layer. I just gingerly, with a fine sandpaper drum, sanded down a corner (grounding area), its a 2 layer board from what I see. I will know more as the project progresses, but this is rather interesting.

There were various revisions of the board, mine is a 1999 model, and has a daughter board for the DC drive about 80% the size of the DC drive - perhaps some revisions of the DC had multi-layer, I don't know, only can comment on what is in front of me - which appears two layer only.

Will confirm once board is trimmed to fit into my case, if this is right or wrong.

UPDATE:

Appears I was right!

Cut off this corner to check, after looking on the board for evidence of pin holes not going through the board

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As you see, two layers!

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So, not only have I shown you can run a DreamCast off 7.4v but also the board is only two layer (making it easier to trim a bit)! :D (it was thought before the board was multi-layered)
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Re: IntoDream - bacteria's DreamCast project

Post by dragonhead » Sun Aug 02, 2009 10:25 am

dont make it only one-game special. kind of defeats the point.

as for cooling, what are you using for thermal compound on the heat sinks? the junk they come with (the little grey pads) is terrible. try switching to something nice like arctic silver or something. also, find some little heat sinks with biscuit fans on them, like what is used for northbridge coolers on motherboards. like this:
http://www.newegg.com/Product/Product.a ... 6835425007" onclick="window.open(this.href);return false;

total height with fan is 24mm. copper is also beneficial to the aluminum heat sinks you are using because it conducts more heat away from the chips.

you can also trim some thickness out of the unit if you get rid of the plastic shell around the rubber mounted disc unit. just fyi.

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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Sun Aug 02, 2009 12:00 pm

Sure, going to make portable for other games too, however I like Quake 3.

Thermal compound - using Asksa 450

Had an update on that, looks like it's on the other forum and not this one (not easy to keep two WIP forums going).

Total height of processor, heatsink and the cooling area I made is about 8mm thick, with the ones you mention, including processor, about 25-26mm. Thanks for the tip though!

Yes, looking into how to make the DC drive smaller, as it is a pain being that thick. Can't easily just position the motor on the board area either, as the main chip is in the way.
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Re: IntoDream - bacteria's DreamCast project

Post by collinE » Sun Aug 02, 2009 1:01 pm

plus those fans and heatsinks are pretty pricey. you're usually pretty good about recycling old pc parts, so yeah... not really necessary.
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Re: IntoDream - bacteria's DreamCast project

Post by tom61 » Sun Aug 02, 2009 3:25 pm

bacteria wrote:As you see, two layers!

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So, not only have I shown you can run a DreamCast off 7.4v but also the board is only two layer (making it easier to trim a bit)! :D (it was thought before the board was multi-layered)
Looks like multiple layers of PCB to me still (it would be one solid color on the sides if it was only one PCB, not green/white alternation), just the grounding area has nothing of value in the separate layers. Still a neat find, but I doubt you could do a chop-apart like on the 2600.

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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Sun Aug 02, 2009 5:54 pm

Someone posted on the other site something that made good sense - his board didn't have a separate board for the drive unit, and he said his board is multi-layer. My boards have a drive board (the size of the drive itself), which might account for being a two layer board instead. I will continue to carefully grind away at the board just in case.
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Re: IntoDream - bacteria's DreamCast project

Post by bacteria » Wed Aug 05, 2009 10:34 am

Got my DreamCast mouse today, and new unused VMU.

The mouse works great, makes a massive difference to games like Quake 3.

My old VMU's screen isn't great, so got a new one.

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Cut off the plug for the CD unit, means each contact will need to be wired directly to the connector on the CD board. The expansion plug was cut off (removed the pins, the plug dropped off) as not needed.

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For the sake of saving about 6-8mm, keeping the CD drive unit intact, from the board downwards, looks like this at the moment, this is my other console's drive unit, as decided probably didn't need to relocate the drive's ribbon cable.

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