voltage for alternate 7800 power adapter

[Mr Egg]

i modified my 7800 hundred to accept standadrd ac adapters . the adapter i am using is rated 8.7 volts 1 amp . its from a bootleg nes all in one system . it seems to work fine but i would like to know from someone who is more electronically inclined if this wont hurt my system in the long run ?

[+Mitch]

The standard 7800 power supply is 9V DC 1A, so it sounds like your alternate power supply should be fine.

 

Mitch

[Mr Egg]

thanks, that gives me peace of mind . i also read about using a sega genesis adapter . but that is 9 vdc 1.2 amps. i know that excess amperages will definetly pop some capacitors so i have stayed away from that option for now

[Bruce Tomlin]

thanks, that gives me peace of mind . i also read about using a sega genesis adapter . but that is 9 vdc 1.2 amps. i know that excess amperages will definetly pop some capacitors so i have stayed away from that option for now

Nope, that's just the CAPACITY of the power supply. If the console wants to use less, it uses less. It's going over the rating of the transformer that's the problem, because the transformer could overheat and start a fire, or the diodes in the wall wart could burn out.

 

The voltage does matter somewhat, since the 7805 reglulator chip works best in the 8-10 volt range. Any higher and it's going to run hot. Any lower, and it won't filter out ripple very well. But whatever you do, don't hook up an AC power supply or a DC power supply with reversed polarity.

[Mr Egg]

that makes sense. but i also read in this forum that some people use 2600 adapters rated 9v 500ma . i understand now that the adapter migth get damaged. would'nt that be risky for the console as well?

[Bruce Tomlin]

2600 adapters are rated for lower amps because they use less power. Lots more chips on the 7800. At the very least you've got Maria, two RAM chips, and a ROM sucking up power. Extra headroom was probably added for the possiblity of hooking up external devices (and carts with more chips, RAM, Pokey, bigger ROMs), which is why the beefier power supply spec.

[+-^CrossBow^-]

here is the deal with using a 2600 power supply. Simply stated, the 7800 needs that 1amp of juice. Actually it only needs about 700 - 800ma. But if you use a 2600 adapter it will work great if all you play are 2600 games. But if you start playing 7800 games for too long, your gonna toast that 2600 adapter. I was testing mine with one, and the adapter began to buzz really loudly after about 10 - 15 min of some 7800 Crossbow.

 

For a quick easy to learn lesson on this, the voltage is just the measure of power if you will. But the amperage is the measurement of how strong that voltage current can be sustained. Or rather amperage is a measure of how strong the voltage stream or current actually is.

 

So, the amps are needed to keep that 9 - 10 volts supplied to the 7800 when needed. Anything less is likely to get burned out since the adpater will have to work that much harder to keep the voltage up.

 

Personally I use a Model 1 genesis power supply that is rated at 10volts and 1amp. Been working great for about 4 years now last I heard.

 

[Mr Egg]

thanks for the detailed explanation . i did want to use the genesis adapter because itst is of better quality . i will keep on using the 8.7volt adapter and keep the genesis adapter as a backup