DreamBox - bacteria's DreamCast project

[IRisH360]

do you think not having a newer version of the dreamcast is gunna hurt you in the end when you try to fit it all in the case since you have that extra board for the drive? just curious?

[bacteria]

Wiring the daughter board to the pins directly and relocate a few capacitors - result will only be about 3mm thicker than not having the board - also, I need to trim a little of the motherboard, which I can do on this board as it is dual layer - the later boards with no daughter board are multi-layer, apparently; which would be very hard to trim.

[Steamdnt]

Just an info bit, While i was making mine, i discovered that two TI cards will make the atteries last longer than the 7808, with a 7808 mine ran for 2 hours, with a Ti it ran for about 2hours 30 mins. Just to let you know

[snowpenguin]

That would be because 78xx and 79xx regulators draw a few hundred milliamps right?

[ctaor]

Hey im trying to do this myself did you use two TI pth08080waz? also how did you set up from the battery to screen and dreamcast im having a bit of trouble understanding?

[bacteria]

I don't need a 7808, as you may have noticed, i'm running the system off 7.4v Li-ions. There is no need to use 12v; a waste of power.

7.4v
>screen directly
>DC motherboard
>extra fan
>7805 (with large heatsink) for 5v (or use another TI card, better)
>TI card for 3.3v

[bacteria]

Relocating the connector ports from the motherboard to the CD drive unit. Each side has 25 wires, all within a 24mm length - that's hard soldering!


There are two things that stop having a slimmer drive system - 1) the motor, 2) the laser - which is about the same thickness as the motor.

So, can we do anything to make the laser mechnism far slimmer? (ie anything compatable that is thin, like a laptop drive unit?

Is there a faster motor for spinning the CD that is slimmer and compatable? (read disks quicker) - eg I have some old CD and DVD drives for the computer, anything I can salage that way?

[tom61]

So, can we do anything to make the laser mechnism far slimmer? (ie anything compatable that is thin, like a laptop drive unit?

Is there a faster motor for spinning the CD that is slimmer and compatable? (read disks quicker) - eg I have some old CD and DVD drives for the computer, anything I can salage that way?

Most drives are incompatible with each other in controlling circuitry. You'd likely have to go through a lot of drives to find a compatible laser or motor assembly, and even then it seems a long shot. Also, a more powerful motor won't help with loading, it goes the speed dictated in firmware.

[sonic4freedom]

i've had 3 dreamcasts 2 with the CD expansion card and 1 without it...so iam taking notes on how to deal with the expanded one...cause it was hard for me to work around them XD

[64M320N3]

That would be because 78xx and 79xx regulators draw a few hundred milliamps right?

No, it is actually because it is a linear regulator, so instead of directly changing the voltage it simply dissipates the difference as heat. Meaning that the volts converted into heat are lost power, and are thus terribly inefficient. Switching regulators are much better.
Bacteria however with his new discovery doesn't need a regulator because he found out that the Dreamcast runs fine off of 7.4 Volts.

[bacteria]

Indeed, no need for a 7808 as only using 7.4v.

The DC also needs 3.3v (TI card), and 5v - used a thick double sided heatsink and 7805 - it gets rather warm (without a large heatsink the 7805 gets extremely hot), so will use another TI card when get around to it for the 5v instead. From what I read, it will also help make the system last longer from batteries too.

[bacteria]

Cool update lads!

Finished the wiring to the connector. Boy, that was very time consuming!! Each wire tested for shorts.



Thought "here it goes, frying tonight!", however it works fine! Past the boot screen, the Sega game screen, loaded the first screen on Quake (where it asks if you want 50 or 60 Mhz).

(removed the corner of the exhaust - the blue tape is to stop debris going into the heatsink/chips area).



Next job will be to relocate some of the surface mounted capacitors on the daughter board and hope it works still (reason is to get the board slimmer). Then secure it in place, then experiment with reducing the drive unit further; then reduce the motherboard a bit. So much to put into the case, including a DreamCast mouse (currently in port 2).

As I haven't been remembering (innocently) to update this thread as well as the ModRetro thread, I need to explain - made a home-made airflow throughfare for a fan assembly with exhaust, to remove the heat from the two chips, which get very hot indeed. The airflow gets rid of the hot air from the heatsinks. The assembly keeps everything as flat as possible. The fan is elevated or it won't fit against the side of the case, and the drive assembly.

[64M320N3]

Wow, that looks like it took forever and a half.
At first glance it looks like it might have been smaller just to leave the connector in, but now you can relocate the board wherever you want, which is nice.
Good update, "my lad".

[bacteria]

Several hours to basically have the height about half the height of the original connector. Between the various modifications (this one, reduce drive assembly, etc), looking to reduce by about 25mm total (as I recall). I need to move the daughter board a few millimeters across anyway, this allows that too.

[64M320N3]

Very nice, very nice.
I should look into portablizing the Dreamcast, as now it simply runs off 7 Volts!
YAY!