Replacement for the neo geo cd power supply? *solved*

maki

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you should measure the voltages, especially the 5V rail
 

maki

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Posts
231
To be more clear:
those PSU should deliver +10V and at least +5.5V, the voltages will be regulated in the NeoGeoCD again.

Using a +12V and +5V is simple not fitting that well IMO, +12V are too high (causes extra heat in the console) and 5V aren't really enough.
It can work, but it can also cause extra stress on the components.

Repairing/swapping caps on original PSUs and using a AC converter 230V -> 115V for EU is a viable alternative.

None of the solutions are cheap, thats the thing about NeoGeo home consoles.

Edit:
what makes these hard to find replacement for is not the dual output, that can be replaced very cheap:
LM2596 cost 1-2 bucks, add a good 12V PSU, few wires and you're good..

the "unobtainium" is the power plug on the NG CD, one would have to print them and then fit plugs

if you have the power plug, then there is IMO better ways to replace the PSU if you don't mind a bit of soldering
 
Last edited:

thearthur

Timid Neo Newbie
Joined
Nov 17, 2022
Posts
6
To be more clear:
those PSU should deliver +10V and at least +5.5V, the voltages will be regulated in the NeoGeoCD again.

Using a +12V and +5V is simple not fitting that well IMO, +12V are too high (causes extra heat in the console) and 5V aren't really enough.
It can work, but it can also cause extra stress on the components.

Repairing/swapping caps on original PSUs and using a AC converter 230V -> 115V for EU is a viable alternative.

None of the solutions are cheap, thats the thing about NeoGeo home consoles.

Edit:
what makes these hard to find replacement for is not the dual output, that can be replaced very cheap:
LM2596 cost 1-2 bucks, add a good 12V PSU, few wires and you're good..

the "unobtainium" is the power plug on the NG CD, one would have to print them and then fit plugs

if you have the power plug, then there is IMO better ways to replace the PSU if you don't mind a bit of soldering
Hi, I already try with a stepdown converter I use the xl4015, but was the same result, just black screen.. I went ahead and take some measurements in both consoles with the generic and orignal AC adapter..
I Measure the voltage regulators too, the NEC 24M08 and the 7805 input and output.

And this are the results:
--------------------------------------------------
+++++++++++++++++++++++++++++
--------------------------------------------------
FRONT LOADER POW CD-J

AC ADAPTER Output ------ Console Measures

10v ------------------------------10.02v
5v -------------------------------- 5.24v

Voltage Regulators Inside Console.
---------------------In ---------Out

NEC 24M08 ------ 9.54v ------ 7.99v
7805 --------------9.52v------- 4.99v

RESULT WORKS GREAT!
-----------------------------------------------

FRONT LOADER GENERIC AC ADAPTER

AC ADAPTER Output ------ Console Measures

12v--------------------------------12.77v
5v----------------------------------5.07v

Voltage Regulators Inside Console.
---------------------In ---------Out

NEC 24M08------12.22v------8.00v
7805--------------12.23v------4.99v

RESULT BLACK SCREEN
--------------------------------------------------
+++++++++++++++++++++++++++++
--------------------------------------------------
TOP LOADER POW CD-J

AC ADAPTER Output ------ Console Measures

10v--------------------------------9.54v
5v---------------------------------5.57v

Voltage Regulators Inside Console.
---------------------In ---------Out

NEC 24M08-------9.23v--------7.96v
7805---------------9.23v--------4.99v

RESULT WORKS GREAT!
-----------------------------------------------

TOP LOADER GENERIC AC ADAPTER

AC ADAPTER Output ------ Console Measures

12v-------------------------------12.52v
5v---------------------------------5.21v

Voltage Regulators Inside Console.
---------------------In ---------Out

NEC 24M08------12.23v--------7.96v
7805--------------12.22v--------4.99v

RESULT WORKS GREAT!
--------------------------------------------------

Sorry if this is a little confusing, but as you can see, the output from the voltage regulators delivers the correct voltage using either the original and generic adaptors. Im just a noob thats why Im not sure why is working that way.. I only found this thread and follow instructions of OP as a viable solution to my problem..

About the plug , that wasnt a problem, I made mine, I made a mold, put some wires inside and then cast some hot glue, the connector never gets too hot to melt the hot glue, I even cant detect any heat at all in the plug, so it works great.. Im sure there are other better ways and materials but thats what I had at hand..

"if you have the power plug, then there is IMO better ways to replace the PSU if you don't mind a bit of soldering". I dont mind to solder, if you can share how to make a better PSU, that would be great!...

Thanks...IMG_20221204_113208.jpgIMG_20221204_113356.jpgIMG_20221204_122416.jpgIMG_20221204_132640.jpgIMG_20221204_193355.jpg
 
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maki

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Posts
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@thearthur great work, really awesome to measure it all and post the results here :)

The pattern I see (and I could be wrong) is if the 5V is really too close to 5V, it won't work.

5v -------------------------------- 5.24v -> works
5v----------------------------------5.07v -> black screen
5v---------------------------------5.57v -> works
5v---------------------------------5.21v -> works

It's what I would expect, the "5V" form the AC adapter should be closer to 6V than 5V, because there is more regulation inside the console, needs more than 5V to work properly.

My POWCD-J has 5.8V without load after a recap, the documentation I found also saus it should be 5.5V instead of 5V.
Those extra 0.5V are necessary to enable the regulation circuit in the NG CD to work stable.
Thats wats causing your problems IMO.

On a side note the 2408 is a LDO unlike the 7805, which are just normal voltage regulators, they are not interchangable, even if the opposite is claimed sometimes on the net.
About the plug , that wasnt a problem, I made mine, I made a mold, put some wires inside and then cast some hot glue, the connector never gets too hot to melt the hot glue, I even cant detect any heat at all in the plug, so it works great.. Im sure there are other better ways and materials but thats what I had at hand..

"if you have the power plug, then there is IMO better ways to replace the PSU if you don't mind a bit of soldering". I dont mind to solder, if you can share how to make a better PSU, that would be great!...
Well Sir if you can make the plug, I'm in awe :)

There is plenty of cheap (1-2 Bucks) DC/DC aka Buck converters sold on the net, based on the LM2596.
Two of them, one configured for 10V, one for 5.5V to 6V, both fed from a 12V PSU.
At least that sounds very simple in my head and won't break the bank.

edit:
example for the the DC/DC converters I mentioned, 15 bucks fo 10 of them, output voltage can be adjusted:
 
Last edited:

thearthur

Timid Neo Newbie
Joined
Nov 17, 2022
Posts
6
@thearthur great work, really awesome to measure it all and post the results here :)

The pattern I see (and I could be wrong) is if the 5V is really too close to 5V, it won't work.

5v -------------------------------- 5.24v -> works
5v----------------------------------5.07v -> black screen
5v---------------------------------5.57v -> works
5v---------------------------------5.21v -> works

It's what I would expect, the "5V" form the AC adapter should be closer to 6V than 5V, because there is more regulation inside the console, needs more than 5V to work properly.

My POWCD-J has 5.8V without load after a recap, the documentation I found also saus it should be 5.5V instead of 5V.
Those extra 0.5V are necessary to enable the regulation circuit in the NG CD to work stable.
Thats wats causing your problems IMO.

On a side note the 2408 is a LDO unlike the 7805, which are just normal voltage regulators, they are not interchangable, even if the opposite is claimed sometimes on the net.

Well Sir if you can make the plug, I'm in awe :)

There is plenty of cheap (1-2 Bucks) DC/DC aka Buck converters sold on the net, based on the LM2596.
Two of them, one configured for 10V, one for 5.5V to 6V, both fed from a 12V PSU.
At least that sounds very simple in my head and won't break the bank.

edit:
example for the the DC/DC converters I mentioned, 15 bucks fo 10 of them, output voltage can be adjusted:
I see, so the problem is that 5V line isnt delivering the correct voltage, Im going to try with a step up converter that I have for that 5V line, and let you know if worked..

I wonder what is that 5V line use for? Because it seems that with only the 10V line they get the 8V and 5V they need to work..
 

maki

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I see, so the problem is that 5V line isnt delivering the correct voltage, Im going to try with a step up converter that I have for that 5V line, and let you know if worked..
yeah that would be my guess

I wonder what is that 5V line use for? Because it seems that with only the 10V line they get the 8V and 5V they need to work..
funny you mention that, I never checked but just assumed is driving the 5V rail
but as it turns out, its only purpose seems to be driving the power circuit which controls the main power rail which feeds from the 10V input.. thats weird


Neo-cda3-1.png
this could mean that a single input voltage could be enough if the power circuit is changed

it says that the 5V power the mainboard..
 
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thearthur

Timid Neo Newbie
Joined
Nov 17, 2022
Posts
6
yeah that would be my guess


funny you mention that, I never checked but just assumed is driving the 5V rail
but as it turns out, its only purpose seems to be driving the power circuit which controls the main power rail which feeds from the 10V input.. thats weird


View attachment 61178
this could mean that a single input voltage could be enough if the power circuit is changed

yeah that would be my guess


funny you mention that, I never checked but just assumed is driving the 5V rail
but as it turns out, its only purpose seems to be driving the power circuit which controls the main power rail which feeds from the 10V input.. thats weird


View attachment 61178
this could mean that a single input voltage could be enough if the power circuit is changed

it says that the 5V power the mainboard..
Its interesting, so its only purpose is to power the board and the 10V delivers power to the rest..

I was thinking that maybe I have some caps in that 5V line that need to be replaced, that could make sense as to why its delivering lower voltage than the top loader..

Well anyway, I try to use a Step up converter, its a mt3608 but I didnt make it to work, its weird, because I calibrate the module for 5.5V or more and I checked with my mulitmeter and all seems right, but in the moment I turn on the console, it inmediatley drops down the voltage to 3.4v or something like that, Instead of step up its steps down, I dont know why, maybe am doing something wrong or the module is broken..

Any Ideas ?
 

maki

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Posts
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Its interesting, so its only purpose is to power the board and the 10V delivers power to the rest..
Actually the 5.5V from the AC DC adapter powers the power circuit, but also the mainboard, if thats too low nothing will start

Well anyway, I try to use a Step up converter, its a mt3608 but I didnt make it to work, its weird, because I calibrate the module for 5.5V or more and I checked with my mulitmeter and all seems right, but in the moment I turn on the console, it inmediatley drops down the voltage to 3.4v or something like that, Instead of step up its steps down, I dont know why, maybe am doing something wrong or the module is broken..
The MT3608 might be too weak for that, it has 2A max output, thats what the old PSU had as nominal value.

Maybe the drop out voltage of 0.5V is too low for it, IOW: from 5V -> 5.5V might be too close for it

sorry I have no real experience with the MT3608
 

maki

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Joined
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Posts
231
I was thinking that maybe I have some caps in that 5V line that need to be replaced, that could make sense as to why its delivering lower voltage than the top loader..
yeah I agree, my guess is the caps in the PSU, also in the NG CD, after 30 years they ought to be dry AF

I replaced all the caps in my POWCD-J the other day, its not many, Nichicon (U)PW series will do, make sure that they'll fit, not much space in that thing
 
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