battery for 2600

[mark]

could someone explain how to power a 2600 with a battery. what battery should be used and how to hook it up? could a 9mm camcorder battery work?

im tring to finish my portable but i need some expert help with this.

[Super-Genius!]

The 2600 uses 9 volts DC and then reduces it to 5 volts DC with a regulator.

So, any voltages between 6-12 volts will work fine. If you go up to

12 volts, I would suggest adding a larger heat sink to the 5 volt regulator.

Or, another solution is to put a small, high watt resistor in series with the

12 volts. Also, make sure your battery is good for at least 500mA.

 

You can cut the wire from any Atari adapter and hook that directly to

your battery. Make sure you have positive going to positive and

negative going to negative!!

[+Mitch]

Actually, you don't really want to go below 7V or the 2600 will start acting flaky.

 

Mitch

http://atari7800.atari.org

[King Atari]

You people are more handy than I am, I could never build a portable.

[badbrad]

If you go up to 12 volts, I would suggest adding a larger heat sink to the 5 volt regulator.

 

What for? I have 3 atari power supplies, and they all put out over 14v DC.

Heck, I have a cigarette lighter adapter I made that I use in my buddy's van on roadtrips.

 

Brad

[mark]

Brad,

 

Could you tell us how you made your adapter for a cigerette lighter in detail? id really like to know.

[Super-Genius!]

What for? I have 3 atari power supplies, and they all put out over 14v DC.

Heck, I have a cigarette lighter adapter I made that I use in my buddy's van on roadtrips.  

Brad

 

Let me explain how those power supplies work. The output voltage with no

load hooked to it does not mean anything! If you checked the voltage

of the adapter when it is hooked up to an Atari AND the Atari is

on, the voltage will be around 9 volts. Atari adapters will output the

stated voltage AT the stated load. With no load, the voltage output is

a lot higher!!

 

So, if you hook up 12 volts to an Atari, you will fry the 7805 regulator.

It may not happen immediately, but it will get hot and "blow". Adding

a heat sink will help dissapate the heat.

[mark]

markdil,

 

what would you recommend doing so my 2600 will not be fried? is there a couple of things i could do?

[Super-Genius!]

Try to find a battery about 9 volts. Then you don't have to make any

modifications. Attach a cable that you cut from an adapter to the

battery. Make sure you have positive and negative correct. Then, you

are good to go!!

[Thomas Jentzsch]

Just a question from somebody who doesn't know anything about hardware at all.

 

Wouldn't it be better to avoid that regulator and directly feed the VCS with 5V? I can see no sense at all in just producing heat especially when using a battery. Maybe somebody can explain me why.

[mark]

markdil,

 

when you say adapter you mean the power supply right? i just don't want to screw anything up. what 9 volt rechargable battery do you recommend? could you please explain how it goes from the battery to adapter in detail cause im really stupid when it comes to this stuff.

[+Mitch]

Just a question from somebody who doesn't know anything about hardware at all.

 

Wouldn't it be better to avoid that regulator and directly feed the VCS with 5V? I can see no sense at all in just producing heat especially when using a battery. Maybe somebody can explain me why.

 

As long as you use a regulated 5V power supply that would work. Most power supplies are unregulated. Hence the need for a regulator in the Atari.

 

Mitch

http://atari7800.atari.org

[Super-Genius!]

You do not use the adapter at all. You CUT the adapter end off, and

use the wire. You then hook the two leads from the wire to the positive

and negative of the battery. Make sure you have them hooked up

correctly! If I remember correctly, the center pin of the plug is positive.

Jameco has a lot of batteries. Here is a 12 volt battery:

 

http://www.jameco.com/cgi-bin/ncommerce3/E...W&search=159661

 

This battery will power your Atari for two hours without having to recharge

it.

[mark]

markdil,

 

thanks you've been a big help.

could i use an atari 800 power adapter to do this? the adapter end is where it goes into the 2600,right?

[mark]

after thinking about your post, i realize how to cut the adapter, battery, to the console. and i figured i can't use an 800 adapter. i had a brain freeze for a little while.

[Thomas Jentzsch]

As long as you use a regulated 5V power supply that would work. Most power supplies are unregulated. Hence the need for a regulator in the Atari.

Thanks.

 

Sorry to ask again (tell me when to stop ), but what means "regulated"? Why is that neccessary? And do batteries need that regulation?

[mark]

i think regulated means it is designed to put out a certian amount of power but i could be wrong

[Cupcakus]

As long as you use a regulated 5V power supply that would work. Most power supplies are unregulated. Hence the need for a regulator in the Atari.

Thanks.

 

Sorry to ask again (tell me when to stop ), but what means "regulated"? Why is that neccessary? And do batteries need that regulation?

 

Basically if we were to use the raw current from the adapter or battery.... Consider we are powering 15 IC's...

 

If all of the IC's are in their low state... the load on power supply is minimal.. so we may see a higher voltage from the supply. If all of the IC's outputs are in HI state... you will see a big load on the supply and the voltage will drop.

 

Think of how many HI's and LOW's an IC will have in the 2600... The TIA is running at 3Mhz... If the voltage in the 2600 was fluctuating up and down based on the load presented by the current state of the CPU and TIA and everything else bad things will start to happen.

 

A radio wave is generated by placing a current on an antenna and fluctuating it low/high very rapidly. The faster the fluctuations... the higher the frequency. So if we are fluctuating the power in a circuit at 3Mhz we are producing a 3Mhz of radio noise that will not only get the FCC knocking on your door (If they found out that is), but will cause chips in the system that are looking for signals to read false signals... and thus your circuit is useless.... :-)

 

Noise is a serious factor in all High Speed circuitry... I am having a hell of a time keeping it down in my Flash Cart.

 

The regulator "smooths" out those fluctuations... If the load is fluctuating in the circuit then the regulator compensates and keeps the voltage at a steady... 5v.

 

This is why you need at least 9v of power on the regulator... So the regulator has room to give for larger loads... If you use a 5v power supply and the load on the circuit increases the regulator has nothing else to borrow from and the voltage will drop below 5v causing problems for sure.

 

It's 3AM but I think this should be a good enough explaination :-)

[Thomas Jentzsch]

This is why you need at least 9v of power on the regulator... So the regulator has room to give for larger loads...  If you use a 5v power supply and the load on the circuit increases the regulator has nothing else to borrow from and the voltage will drop below 5v causing problems for sure.

 

It's 3AM but I think this should be a good enough explaination :-)

Yes, I understood now.

 

Aren't there any more advanced (though expensive) solutions to the problem?

 

E.g. AFAIK my stereo amplifier has some big power buffers (don't know the technical name) that he uses to "borrow" from.

 

Especially when using a battery, wasting any power should be avoided.

[jsoper]

I researched this stuff for my portable 2600. It seems that the current draw of a 2600 changes depending on the cartridge. I measured readings of 220ma (adventure on a cmos multicart), to 280ma (regular adventure cart), to 330ma (Pitfall2 cart). Changing the 6507 to a 65C02 could get it lower if someone wants to try.

 

Next step was to remove the regulator and supply 5v directly. The 2600 still worked and the current readings were the same. Then I varied the supply, the system was functioning from 4.4v to at least 6v (didn't want to take it any higher). However there were two problems, the audio was off at both ends and there was a really bad color shift. Turns out the TIA color ref pin needs to be at a constant voltage (4.2v on most TIA's) to keep the colors correct. This voltage is what the color pot adjusts on a 2600.

 

I then changed the pot to a voltage reference using three diodes with a pullup resistor. One diode was a 3v blue LED which got me to 4.2v when the other two were added in. This kept the colors nice within about a .8v power supply range. The next step was to add a three position switch so the input power to the 2600 could be dropped by 2 diodes(1.5v), 1 diode(0.75v), or 0 diodes. This gives me good color on my portable as the battery voltage slowly drops from almost 7v to below 5v.

The final batteries I used were two Radio Shack 6v RC NiMh rechargable batteries, 1500 ma-hours each.

You can see the voltage dropping switch and the blue LED (looks white because of flash) here:

http://dreamwater.net/tech/abbibi/2600.html

John

[somePUNK]

couls you hook up 6 1.5 volt D cells and run it off that i know nothing just a question?