Compiled a shorter version of the worklog to date here, keeping it relevant and compressed; followed by a video of the work to date, taking footages from the three WIP videos into one updated one.
* D-pad (from a different controller)
* Joystick - N64 SuperPad 64 controller (more accurate and easier to use than stock one)
* VMU unit built in with its screen showing through case. Only 1 VMU is needed anyway, holds a few game saves!
* 4 button pad
* Variable left and right shoulder buttons
* Pop-up CD tray
* Swappable slanted D-pad / screen controls (Q*Bert game)
* PSone screen and lightly trimmed board
* Stereo speakers
* Original hardware
* Low battery indicator
* Internal batteries - not sure of space available at moment but will be between 4.4 amps and 8.8 amps. System needs about 2.7 amps to run.
I found that the Dreamcast doesn't need 12v to run, it runs fine on 7.4v, and cooler too. Using 7.4v instead of 12v in a portable is far better as the PSone screen uses 7.4v so saves using a 7808 to reduce the voltage down (and make extra heat in the process) and extra batteries to make the voltage up to 12v in the first place.
Instead of using a PicoPSU to take in 12v and output 12v, 5v and 3.3v(and 7808 as above); I can just use my 7.4v to power the screen directly, and the 12v line, just need a TI card step-down regulator for 3.3v (approx) and either a second one for 5v, or a 7805 with a large heatsink. The TI card is better in reality, as it is more energy efficient than a 7805 and the system is not going to trip out if the 7805 gets too hot.
The DreamCast opened:
The part on the left is the board that normally takes in AC power and converts to 12v, 5v an 3.3v DC. This board is not needed in a portable.
The older DC boards (like mine, 1999 model) have a separate daughterboard for the drive unit, newer models had the electronics built into the motherboard - the relevance of this is not just the obvious factor of a later board being easier to mod, but the negative aspect if you need to trim the board at all, that the ones without the daughterboard are multi-layer motherboards, not dual layer like the DC with the separate board. Double layer boards are fine to reduce, but multi-layer - no!
See - two layers:
Here is the drive unit and board:
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.
Here BTW is the pinout for the video and audio:
According to daftmike, the DC uses, if using 12v instead of 7.4v, when he tried my set-up:
3.3V ~ 2200-2400mA
5V ~ 450mA
12V ~ 180-200mA
He carried on by saying "loading didn't seem to be affected and current draw overall was only 1900mA at 7.5V. This is about 20% less power than when running at 12v with a gc power board."
Thus, 1.9 amps for the system and another 0.7 amps for the PSone screen = about 2.6 amps, add a bit on for extra fan and VMU, call it 2.7 amps. That is a lot - put it this way, the battery connectors originally in my video get very hot after a minute or less; meaning thicker wires needed!
Removed the metal shielding and the stick-on heat transfer pads from the chips, gave them a good wipe to clean them, applied a little of the thermal paste and spread it with the plastic card, thinly on the two chips. The heatsinks are quite slim ones.
Pic of one of them ready for heatsink.
Done, as there was some surplus metal on the heatsink, hot glued these edges to the motherboard.
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 - 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! The Blu-tac will not get hot as the fan will keep it cool with the heatsink air, so not an issue.
I got the idea from two things - one from a laptop fan, where two chips are thermal pasted onto a metal plate and a fan at the other end helps to cool the metal plate, and provide exhaust; and the PC blower fan. My concept is virtually free in cost, same idea, and also slim - the heatsinks are about 4mm tall, the card is about 2mm thick mounted.
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).
Blu-Tac pressed into place, to provide an airtight seal:
Removed the male and female connector of the drive board to the main board, re-wired it.
25 pins within 24mm space. 4x (two per side, two boards). 100 really tiny solder joints. One mistake could mean disaster. Literally hours to do this!
As damaged some of the pins removing the connector on the drive board, wired straight to the component joints in many cases:
To get the VMU in the case, it needs to lose height, so there is space for the 4 button pad board.
Put 4 x AA's in replacement for the two 3v watch batteries (6v); although, as tested before, works on 8.3v ok.
This is my new VMU, dated 2000, circuit is nearly the same as the 1999 one I used first - the LCD detached and therefore didn't work anymore on the board, so wrong to say it fried, but it is dead.
On this one, hot glued the sides to the board to stop it happening again!
Front and back:
Cut the board up (along blue line in first pic)
The VMU doesn't need batteries for game saves, uses batteries either to play crappy games as a stand alone unit (apparently chews through watch batteries), or for saving the time/date settings. If the batteries are flat or missing, then the DreamCast system asks you to enter the details. Pain. As the VMU seems to work fine on 8.3v, and seems to demand close to 6v to work, the VMU can be permanently connected to the Li-ion cells, irrespective of if the console is on or not. That will preserve the time/date.
These are the 6 capacitors I was referring to before - need relocating.
Done and working:
Wired up the audio and RGB. Keeping composite there too at the moment as using that as an easy way to know the system works at the moment. Audio is not connected to the screen yet, just to the plug.
Mad soldering skillz again!!
This controller is better than the original one as the contacts are normal, not via magnets:
Look - shoulder buttons use one of the variable thingies you have on jotsticks!
And here - joystick uses stock 3rd party joystick! YAY!