How do you determine what's burned out?

[Video]

I've seen lots of people come in and discuss a problem with their 2600's, and someone comes in and says "you need a bloorellooo" and it just happens to be the right part. But How do you tell what's broken?

 

I have several systems that don't work, and as far as I can tell, looking internally, nothing's burned or blown out. And since the screen shows nothing, or static, how do I determine what the problem piece is?

[Inky]

"How do you determine what's burned out?"

 

Either give the subject a breathalizer test, or look for 'roach clips'

[Ian Primus]

Determining what is wrong with an Atari takes intuition and a good familiarity of how the machine works, and what common symptoms are. Also, opening up the Atari and measuring voltages is a good start. Sometimes the voltage regulator dies, and can fail in different ways. Controller port problems like an Atari that always thinks the joystick is pointing some direction, or that a fire button is being held down, even when there is no joystick connected is usually the RIOT, video problems like flakey or garbled graphics is generally a TIA failure, etc. Ataris don't normally break often, but I am seeing more and more problems as time goes on. Diagnosing and repairing Ataris takes a good knowlede of basic electronics, some basic tools (a good multimeter is your friend), the ability to solder, as well as just general familiarity of all the innerworkings of the beast. I have actually sat down and traced out most of the circuits on a 2600 before, most are pretty simple, and the fact that the Atari only really uses three chips helps also. But, most importantly, I love fixing things, and I love electronics, so Atari repair is something I really enjoy. It's hard to get good at something if you don't like doing it.

 

Ian Primus

ian_primus@yahoo.com

[CPUWIZ]

Having one of these also helps a lot.

[bjk7382]

Determining what is wrong with an Atari takes intuition and a good familiarity of how the machine works, and what common symptoms are. Also, opening up the Atari and measuring voltages is a good start. Sometimes the voltage regulator dies, and can fail in different ways. Controller port problems like an Atari that always thinks the joystick is pointing  some direction, or that a fire button is being held down, even when there is no joystick connected is usually the RIOT, video problems like flakey or garbled graphics is generally a TIA failure,  etc. Ataris don't normally break often, but I am seeing more and more problems as time goes on. Diagnosing and repairing Ataris takes a good knowlede of basic electronics, some basic tools (a good multimeter is your friend), the ability to solder, as well as just general familiarity of all the innerworkings of the beast. I have actually sat down and traced out most of the circuits on a 2600 before, most are pretty simple, and the fact that the Atari only really uses three chips helps also. But, most importantly, I love fixing things, and I love electronics, so Atari repair is something I really enjoy. It's hard to get good at something if you don't like doing it.

 

Ian Primus

ian_primus@yahoo.com

 

Or you can just post a question on atariage and let other people do the work

[Video]

Yeah, if the screen came on, it'd be easy to track down the problem. I got a voltage regulator around here I useually use for testing batteries, will just any one work, or is it a particular one?

 

That manuel is cool. But if it calls for the same things my Vectrix manuel calls for, I'm afraid it wouldn't be much use.

 

Some of the things it lists that I supposedly need.

Screwdrives,

Resistors (of varying capacity)

Oscyliscope (? Huh? You mean like a radar scope? WTH do I get that?)

 

Of course, Atari has less parts, and no tube, so it should be a lot easier.

 

Most simply show a blank screen, so I need to track down what's wrong, probably power, I hope, it'd be the easiest to fix. But I'd hope for a blown resistor somewhere, their easy to spot.

 

Yeah, I guess I could just post what they are doing on Atari Age, but I want to get into fixing the things myself, and I got a few and don't want to harass the local members daily lol

[Ian Primus]

Yeah, if the screen came on, it'd be easy to track down the problem.  I got a voltage regulator around here I useually use for testing batteries, will just any one work, or is it a particular one?  

 

That manuel is cool.  But if it calls for the same things my Vectrix manuel calls for, I'm afraid it wouldn't be much use.    

 

Some of the things it lists that I supposedly need.  

Screwdrives,  

Resistors (of varying capacity)  

Oscyliscope (? Huh?  You mean like a radar scope? WTH do I get that?)  

 

Of course, Atari has less parts, and no tube, so it should be a lot easier.  

 

Most simply show a blank screen, so I need to track down what's wrong, probably power, I hope, it'd be the easiest to fix.  But I'd hope for a blown resistor somewhere, their easy to spot.

 

OK, for basic Atari repair, you need the following:

 

Phillips head screwdriver

needle nose pliers (to get the RF sheild off easily)

small flat blade screwdriver or butter knife (to lever chips out)

soldering iron

multimeter

time

 

Start by taking the cover off, and removing the RF sheild. If you get a totally blank screen, the first thing to check is the power regulator. It is located on the lower left side of the board. The Atari uses a 7805 voltage regulator to step the 9 volts from the AC adapter down to 5 volts for the logic. Without it, the Atari can't do anything. The first test would be to measure the voltages at that regulator. Plug in and turn on the Atari, and set the multimeter for DC volts. The voltage regulator has three pins. Touch the negative lead of the multimeter to the RF sheild, or to the metal square where the RF shield was. This is all ground. Touch the positive lead of the multimeter to the pin on the voltage regulator closest to you (looking at the board from the front) If you get anything other than five volts, the regulator is the culprit. Replace it. If it is putting out five volts, the start looking elsewhere, it's probably a blown chip.

 

Further problems are more complicated, you can try testing the voltage at the cart slot, pin 23 is +5v (second pin from the upper left, looking down into the slot from the front), but test it from the solder pad on the back, it's a lot easier to get to. If that pin reads five volts, then the power part of the system is good. Try swapping chips with another working Atari, one chip at a time, and see if you can find the culprit. (Hint: start with the TIA, then the CPU)

 

To remove chips:

Before removing the chip, note the orientation of the notch, which indicates pin 1. To remove the chip, insert a thin, flat object such as a butter knife or a small flathead screwdriver between the chip and the socket at one end. Lever the chip up a tiny bit, and then repeat on the other side. Do this until the chip is free. To insert a chip, line the pins up with the holes in the socket, and gently press it until it starts to slide in, making sure that all the pins are going into the holes, and not bending out or in. Press firmly until the chip is seated.

 

A couple of tips:

 

Don't force the chips out of or into the sockets. You don't want to bend or break off pins.

 

Don't use one of those "IC Extractor" tools that Rat Shack sells. It's not going to help, and often makes the problem worse, since the chip will suddenly pop loose at one end and not the other, almost always resulting in bent pins.

 

Always remember the orientation of the chips. There will be a notch in the chip in the form of an indentation on the top, an indentation on one short side, or a large cutout on the top of the chip. You'll know it when you see it. If you're paranoid, mark the tops of the chips with a pencil.

 

Careful of static electricity. You don't want to zap your any of the chips. Ground yourself by touching the screw on a lightswitch cover, or the metal case of your computer.

 

 

 

There is a lot more to fixing Ataris than just swapping chips around, but that will generally narrow down where the problem is, and in many cases, help solve it.

 

Ian Primus

ian_primus@yahoo.com

[Video]

That sounds easy enough. What about JR atari's? Same thing? I was just wondering because they're soldered in rather than plug in chips, at least on the one I took apart. I don't have to worry to much about that though, as I only have one of those.

 

Thanks for the help. I actually have everything I need for the 2600. But I'm not supposed to use a chip extracter huh? Well, I figure a knife or screwdriver would be easier anyways.

[povlok1]

Determining what is wrong with an Atari takes intuition and a good familiarity of how the machine works, and what common symptoms are

 

Ian Primus

ian_primus@yahoo.com

 

 

I just set it up against the wall and throw a dart at it.. im pretty lucky that way

 

Ian like me has done a few of em:) would of said just the same myself;)

[Ian Primus]

What about JR atari's?  Same thing?  I was just wondering because they're soldered in rather than plug in chips, at least on the one I took apart.

 

Yeah.... It's the same principle, but on an Atari 2600 Jr, you'll have to desolder every single pin, one at a time, to remove the chip. It's a pain. But, once you've gotten the chip out, put a socket in to save your sanity in the future. Desoldering large IC's is not something for the faint of heart, or at least not for those who have done a lot of this sort of thing. The problem is, that to remove the chip, every pin must be free, and that generally requires sitting down for an hour with a soldering iron, solder sucker, and a steady hand. Now, if you're _positive_ that the chip is bad, you can take a small pair of dikes and clip all the pins off as close to the chip body as possible. Then, you can heat up all the pins, one at a time, and pull them out. This is definitely easier, but you want to be sure the chip you are removing is bad.

 

There was one revision of the Atari 2600 Jr. that used one single chip as opposed to three. I haven't had to work on one before though. Something tells me that tracking down _that_ chip would be nearly impossible.

 

Ian Primus

ian_primus@yahoo.com