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Original PSU resistor?

Posted: Wed Apr 08, 2020 6:38 am
by Stu1872
As i have a GDEMU in my Dreamcast i have read that the power supply runs hot due to not using all of the voltage from the GD ROM drive.

I have read that using 3 1Kohm resistors (in parallel) will help reduce the power output and thus produce less heat.

Has anyone done the resistor trick on the PSU rails?

Re: Original PSU resistor?

Posted: Wed Apr 08, 2020 7:09 am
by NightBreeze
I did it before I got a picoPSU for my Dramcast. To be honest I'm not sure if and how much that resistor helped. Maybe a little but it's probably more effective to remove the 12V line entirely.

Re: Original PSU resistor?

Posted: Wed Apr 08, 2020 10:52 pm
by TruREALigion
Its not a resistor, but I believe its a regulator. Facing the dreamcast, its the heatsink closest to the pin connector in front, and the right one. First you unscrew from the heat sink, then desolder it off. I did it for my USB-GDROM. NTSC Dreamcast

Re: Original PSU resistor?

Posted: Thu Apr 09, 2020 12:10 pm
by NightBreeze
TruREALigion wrote:Its not a resistor, but I believe its a regulator. Facing the dreamcast, its the heatsink closest to the pin connector in front, and the right one. First you unscrew from the heat sink, then desolder it off. I did it for my USB-GDROM. NTSC Dreamcast


There are two methods of reducing heat from the DC PSU. One is removing the regulator like you're talking about. This disables the 12V line entirely. The other method is simply adding resistors between 12V and ground. That, in turn, puts load on the 12V line and reduces heat (feels a bit backwards, but works to an extent) :D

Re: Original PSU resistor?

Posted: Thu Apr 09, 2020 2:38 pm
by Stu1872
I am not very handy with a soldering iron tbh. I have tried before with not very good results. Probably due to me not using any flux.

I have ordered some liquid flux and a de-soldering pump a couple of days ago when i ordered a new rechargeable battery and holder for my Dreamcast so if i don't mess up the battery replacement i will give the regulator removal a go.

I was eyeing up the ReDreamPSU and PicoPSU to replace my PSU but the money spent on this project is starting to pile up with me already buying a VGA to HDMI cable, battery holder, rechargeable battery, 2 new 4mb memory cards, 2 extension cables for the gamepads and fan mod with a Noctua fan.

Re: Original PSU resistor?

Posted: Wed Apr 15, 2020 8:18 pm
by areyareadyherewego
the benefit of a resistor is if you need the gDROM, its easy to swap back. not so if you remove the 12v rail

Re: Original PSU resistor?

Posted: Thu Apr 16, 2020 2:45 pm
by megavolt85
the resistor has no advantages
This is a stupid mod from a person who does not think in electronics

Re: Original PSU resistor?

Posted: Fri Apr 17, 2020 5:20 am
by Stu1872
megavolt85 wrote:the resistor has no advantages
This is a stupid mod from a person who does not think in electronics


If you are referring to me then yes i don't have much knowledge in electronics but i am just going by what i have read online. I installed the 3 1Kohm resistors in-parallel across the 12v/ground after reading this page online. https://retrogamesultra.com/2019/02/17/ ... and-setup/

If there is a better alternative then i am all ears as to what it is. I plan on playing this console for many years would like it to run as stable as possible.

Should i just remove the part that is continuing to provide the 12v that is unused since i have removed the GD-ROM for a GDEMU?

Is this the part in these pictures?
Image
Image

Re: Original PSU resistor?

Posted: Fri Apr 17, 2020 11:22 am
by megavolt85
Stu1872 wrote:If you are referring to me then yes i don't have much knowledge in electronics


I did not mean you, but the person who proposed this method

Stu1872 wrote:If there is a better alternative then i am all ears as to what it is. I plan on playing this console for many years would like it to run as stable as possible.


look at the photo in my previous post
you need to cut one track and solder the jumper