unebonnevie Posted November 1, 2015 Share Posted November 1, 2015 Hi, I just got an Atari 7800 from eBay, and, as usual, it does not come with the power adapter, which has an insane strange connector. So, I am going to do a power mod. I have a 9V DC and 1A output adapter, as stated on the power adapter's label. When I measure the voltage output, it's always 12.47V. Pretty strange. So, I was looking at the Atari 7800's schematic but can't find if it has some sort of voltage regulator (like the 7805 voltage regulator) to ensure 5V is what all the chips on the motherboard get, even with 9-12V input. So, is 12V to high, even the adapter says it has a 9V output. By the way, why does the power adapter has higher output than it claims? Thanks! Quote Link to comment Share on other sites More sharing options...
CPUWIZ Posted November 1, 2015 Share Posted November 1, 2015 It does have a 7805, it is behind the cart slot, mounted to a huge heat sink. Quote Link to comment Share on other sites More sharing options...
Shawn Posted November 1, 2015 Share Posted November 1, 2015 You can use up to a 15v power supply no problem. Watch the amperage though, too high on that and it's gonna pop. Quote Link to comment Share on other sites More sharing options...
desiv Posted November 2, 2015 Share Posted November 2, 2015 Not very familiar with electronics, but I didn't think you could have "too much" amperage per se. I thought that the device pulls what it needs. So as long as you have "enough", having too much available shouldn't be a problem. The PSU doesn't push all those AMPs to the device???? desiv Quote Link to comment Share on other sites More sharing options...
BigO Posted November 2, 2015 Share Posted November 2, 2015 On a typical non-regulated supply, the unloaded voltage will be significantly higher than the rated voltage output. 12-13 is nothing to be scared of for a 9V rated supply. It'll drop right down when it sees a load. The board itself actually operates off of 5 volts. The aforementioned regulator in the console takes care of that. As I recall, those regulators will typically handle input voltages over 25 volts with no problem. 1 Quote Link to comment Share on other sites More sharing options...
Osgeld Posted November 26, 2015 Share Posted November 26, 2015 25 volts yes with little to no load cause its dropping 20 volts as pure heat 12 volts is fine you cant have too much current from the system side of things it will only take what it wants, from the power supply side of things if its unregulated and your not using 60-70% of its current capacity, the loaded voltage wont fall into line, which goes back to point 1, more voltage in, the more the regulator has to burn off as heat Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.