I bought a Sega Genesis
model 1 from a local thrift store recently for $10. It was sold as "broken, for parts only". It didn't come with any cables.
I've repaired several vintage gaming systems in the past so I took a chance on seeing if I could repair it.
When I got home I realized that I didn't have a proper power supply for it. I have several Genesis model 1's and 2's but the only power supplies I had for them were for the model 2's. Which takes a smaller barrel plug.
Anyway, first thing I do is Google the power requirements for a model 1 (couldn't find it listed on the actual unit) and after some investigation, it appears the model 1 needs 1.2A/9V DC. I'm going from memory but that should be pretty close.
So I dig in my parts bin and I cannot find anything that fits and has those specs (several 1A but no 1.2A).
Next I get on eBay and find a vendor that claims to have sold thousands of power supplies for Sega and claims he has exactly the one I need. His ratings were good but when I asked him the specs, he said it was 350mA and 10V. Well, I figured the 10V would probably be OK but the 350mA seemed too weak. He assured me it would work (and it was cheap) so I bought it.
It arrives and when I plug it in, it worked like a champ. Total investment $19.95 for a working Sega Genesis.
My question is, how is this possible? Are the 1.2A specs online just simply too conservative? I have tons of 500mW supplies so they would probably work too. How can I "properly" tell what kind of power a unit like that REALLY needs?
EDIT
Sorry, I meant 350mA
NOT 350mW
.