Replacing the DC PSU

^ did you test with the original gd-rom when it is working?
also no need to get a smaller picoPSU, the 160W is just fine and "working lightly", that's a good thing

IMHO you should really pay attention to your external PSU , IIRC you are using a 1.5A one? For reference , if you want to use that 160W pico with a pc build or something, you need an external PSU that offers 12.5A/12v to feed to the pico so it can deliver the amperage on it's datasheet. Obviously the DC does not need such a beefy 12v input to the pico, but for peace of mind try to find a 3~4A psu...

 

I think it's used for the gd-rom motor, I know the gdrom daughterboard requires it.

 

That's great it works without 12v. I'm hoping the gdemu is the same (I think it should be). I just ordered the same power supply that's in the OP instead of risking it with a cheap $2 supply. This should really cut down on the heat generated.

i also ordered this to try:
http://www.ebay.com/itm/281107235257

 

This won't be powerful enough, sorry.

According to Rocky5 measurements, you need 2.5A @ 3.3v and 2A @ 5v to be safe.
The board you posted yields 1A @ 5v and 700mA @ 3.3.v

 

It will hopefully be enough if I power it with 6.5v. He said it was lower when he used 9v (I know it wasn't much though). I don't really see how it could be needing that much current withou the Gdrom drive. I'm not sure if he is running his usb hard drive off that or not also. I have a gdemu and it may not have as much current draw was the Usb-controller also.
i also have some 1.5a 7805s that I can replace the 1a on the board with if needed.

 

Sorry, but the board you posted can only outputs around 7W, which will never be enough.
The one I posted might also not work in the end, I suspect it can outputs 3A at 5V, but then re-regulate that 5V to 3.3V. In which case it wouldn't be enough.

 

You are probably right, but I will probably try t anyways. These are numbers bacteria posted in his portable thread:
3.3V ~ 2200-2400mA
5V ~ 450mA
12V ~ 180-200mA
and that is with the Gdrom drive I think. Rockys 5v measurement is quite a bit different so I'm not sure. That could be the addition of the usb controller.

ill measure the current draw on mine when I get a chance to see if there is a difference between the usb-controller and the gdemu. I guess then I'll know if it will work or not (most likely not).

 

Yeah it seems logic that USB would require quite a lot more power on the 5V line, especially with a disk attached.
At worst, one could use two LM2596-based buck converters (around 3.5$ for both) for each line. Each of those yield 3A at either 3.3v or 5v (potentiometer adjustable).

Numbers with a gdemu would be nice.

 

Yeah. No reason for me to keep speculating. I'll hopefully have time to measure it with the stock supply and gdemu tmorrow morning.

 

The 5v amps are with a USB bus powered HDD connected, though the drive requires less than 1amp. (But that probably what lifted it above 1)

wait, I also have a Hanzo connected, that outputs 5v on pin9.

i also also just purchased a better external DC plug, 6A 72W, so more than enough amps & watts for the DC.


Update:

5v current.

[Hanzo, UGC & USB Bus Powered HDD]
1.70A

[Hanzo & UGC (no HDD)]
1.45A

[Hanzo only]
1.32A

[UGC only]
1.28A

[Nothing bar a control pad on port 1]
1.15A

It would seem with nothing bar a pad connected, my DC uses 1.15A on the 5v rail. (Only load would be the MB)

Note this is a PAL system.

so all in all with everything connected we need a power supply (DC external plug/wall wart) with 5amps minimum. (Thought the 1.5amp plug I have been using works fine?)

 

That makes sense. I'm betting that the 3.3v draw will be similar with the gdemu. Possibly even higher since the sd card uses 3.3v. So most likely I'll end up using the pico supply. Would have been nice to have one that was just 5 and 3.3v though.

 

good call on the 12v psu Rocky5 , 6A is great for this...
Although the 1.5A one was working it was not safe IMHO for long term usage - since the DC needs more juice - it would kick the bucket sooner or later...

 

I guess if you want more current you could replace the voltage regulators with beefier ones
if I was making a portable id skip using a Psu and just wire up some beefy low drop out regulators for each line straight up too the source (battery) then just cut power from the source, iirc that's how the stock set up works (cutting source to turn off or on))

 

This is a great thread - I will get one of these for sure when its clear which is best. This will help bring temps down inside the DC with my GDemu and will be a big space saver inside the DC.

Good stuff.

 

I hooked up mine and got about 250mA on the 5v line and 2.2A on the 3.3v line. I dont think the 3.3v measurement is accurate though as the Dreamcast would not boot with my meter in the 3.3v circuit. The consoles LED did not even light up. Not sure why it would not work. I tried changing out the battery in my meter, and both current settings on the meter and it did not help. Good news is the the GDEMU appears to work fine too without 12v.




This was measured using composite video as my Hanzo cable would not reach far enough to get on the floor so 5V current will be a little higher with a VGA box. FamilyGuy, you were correct that the little 5v and 3.3v ps will not work.

 

You could use this for saturn

 

I was thinking, is there a modification that can be done on the stock psu and disable 12v output completely? Anyone has the knowledge to find this?

 

Cut the trace leading to the pin, thought that wouldn't stop the PSU getting hot.

 

^ yeah, that's not a great solution, I am thinking something along the lines of removing a regulator or a component and disable the 12v creation completely.
The picopsu idea is great , what stops me is the external brick... I don't really like having one on the DC.
I also experimented with replacing the stock fan that is noisy like hell, it's so hard to get a 30x30mm one that has decent airflow....

 

Didn't the thread starter used a wall AC/DC adapter? 12V 1.5A IIRC. This isn't that big and at 18W, it's just over the power the DC uses with an ODE. You can also find 2A (24W) or 3A (36W) adapters fairly cheap if you wanna be safe, but the former is hard to come by in a small "wall" form factor (check on amazon). It'd also be possible to fit such converters in the console with the room removing the original PSU gives!