Different colours when using a different power suppy?

[the_wizard_666]

Hi everyone! I've been a long time lurker here, but when doing some repair work on a console I found something weird that I just can't figure out, so I signed up to ask the pros!

 

So here's the story - I have a Vader that needed a new video cable, so I replaced it. Big whoop. I tested the system out with the power supply from the system I have set up, and it worked great. However, when going through my box of power supplies to find one to put with it, I found one that, when used, boots the game with a different colour palette than the one I've already got hooked up. I was testing the system with a copy of Blueprint (I just grabbed a random cart, and that was the one I grabbed). The only thing I can think of is that the power supply has a lower output than the standard one, but I'm not sure why it would change the colours in that case, rather than not booting the game. From what I can tell the game works properly, but the colors are different.

 

Now, a reason for the above situation would be cool to know, but the big thing I need to confirm is whether or not I should use this adapter with the system or not. I appreciate any insights and tips that you guys can provide.

[+Stephen Moss]

You should use an power unit with an identical voltage and current specification to the original (9V DC @ 500mA), just one of those matching could cause problems due to low input voltage or possibly high ripple voltage.

Do you know what the output specification of the both power units are and how they compare to the above spec?

Have you measured the outputs of the power units to see if they as expected (around 12-14V with 2600 off & 9V with it on)

 

I am only guessing here but a low voltage (or ripple voltage) out of the internal regulator can result in a slight change in frequencies and chroma/luma signal voltage and it may be one or both of those that is throwing the colour off.

[the_wizard_666]

Well, the one I have hooked to my main unit is an official 2600 adapter, so without confirming I would assume the specs line up properly. The second one is marked as a 9V DC 100mA output. I guess that is causing it then?

[+poobah]

Well, the one I have hooked to my main unit is an official 2600 adapter, so without confirming I would assume the specs line up properly. The second one is marked as a 9V DC 100mA output. I guess that is causing it then?

 

Yup, nowhere near enough current.

[+Stephen Moss]

Well, the one I have hooked to my main unit is an official 2600 adapter, so without confirming I would assume the specs line up properly. The second one is marked as a 9V DC 100mA output. I guess that is causing it then?

 

Yes, that is probably the issue.

As the 2600 tries to pull 500mA out of it the supply voltage it will cause the output voltage to drop to far to correctly power the unit. With unregulated power units (as most of that type are) it is critical to use a replacement with a matching output voltage and current rating to that of the original unit otherwise you can have either under voltage or power dissipation problems.

Edited March 27, 2017 by Stephen Moss