Dangers of Naki multi-head retro game power supply?

[sparf]

Hi again guys,

I want to say this forum has been immensely helpful to me in recent days and I really appreciate all the help. This one baffles me because I can't help but think I'm somehow being stupid with my multimeter. And if so, I deserve the mocking I'll no doubt receive. I have 2 identical AC Adapters designed with 3 output heads (one Genesis, one NES, and one SNES barrel connector). After having a realization that the psu I was given with my X'Eye when I bought it was a Genesis 2 and likely could cause harm, I decided to check these adapters out to make sure what they were outputting.

The label says 9v, 1A. My little baby multimeter can't go above 200mA but it can test voltages up to 500VDC. I set the dial to 20V (the first setting above the expected amount, as I was taught to do).

These bastards are outputting a steady 13.3 volts to all 3 connectors! I don't know what the amperage is because I no real way to test that in-series with this little baby multimeter but that can't be right can it? If it was one of them I'd say, oh, there's a failed adapter, but 2 outputting exactly the same and completely consistent is troubling.

I bought these both at Gamestop during my tenure there from 2000-2003. They have a label on the back that says they are made by a company called Naki. I bought them very late in my tenure, so a decade old, I guess they could have gone bad, but two of them?

[Tokimemofan]

Hi again guys,

I want to say this forum has been immensely helpful to me in recent days and I really appreciate all the help. This one baffles me because I can't help but think I'm somehow being stupid with my multimeter. And if so, I deserve the mocking I'll no doubt receive. I have 2 identical AC Adapters designed with 3 output heads (one Genesis, one NES, and one SNES barrel connector). After having a realization that the psu I was given with my X'Eye when I bought it was a Genesis 2 and likely could cause harm, I decided to check these adapters out to make sure what they were outputting.

The label says 9v, 1A. My little baby multimeter can't go above 200mA but it can test voltages up to 500VDC. I set the dial to 20V (the first setting above the expected amount, as I was taught to do).

These bastards are outputting a steady 13.3 volts to all 3 connectors! I don't know what the amperage is because I no real way to test that in-series with this little baby multimeter but that can't be right can it? If it was one of them I'd say, oh, there's a failed adapter, but 2 outputting exactly the same and completely consistent is troubling.

I bought these both at Gamestop during my tenure there from 2000-2003. They have a label on the back that says they are made by a company called Naki. I bought them very late in my tenure, so a decade old, I guess they could have gone bad, but two of them?

You aren't testing it right, these power supplies do not have voltage regulators in them, because of that fact these will output the proper (and much lower) voltage only when connected under load (ie the system). Using the same test on my gameboy color ac adapter shows about 5 volts (those run on 3V).
read this: http://en.wikipedia.org/wiki/Voltage_drop

[sparf]

THanks! That makes so much sense now!

My other question then is does it drop to the needs of the system it's connected to, or does it drop to within 10% of the rated voltage regardless? For example, technically the Genesis used 10v. Is it just giving it a a roundabout voltage or is it closer to the 10?

Until I found out the amperage was too low I had used this to power my X'Eye for a play. In retrospect at least it had higher amperage than the Genesis 2 adapter that shipped with the system.


I have another question regarding this type of adapter. I have a 9v, 1500mA adapter from RAdio Shack. It tests out without load at around 9v. Would it be subject to this kind of voltage drop or does it likely have a regulator? I ask because other people on Youtube have used this exact adapter to power an X'Eye successfully but for me it does not power on.