Fixing some broken 2600s

[Chainclaw]

I've got a pile of broken 2600s. I want to fix them.

 

Lets start with a Junior.

 

I'm getting power, the little red LED light is turning on, which I'm so glad is there, it saves me from chasing down that path.

 

I am getting no signal on the TV at all. I don't even get the usual static-changing when I turn the system on, that my other broken systems give.

 

Any ideas? Anyone have any good notes on fixing up Juniors? I've gone over most of the board with electronics cleaner, and no good.

 

I'll add pictures tomorrow if we get nowhere from here.

[bah]

Good morning.

 

First find the atari 2600 service manual and download it. It was written for the 6 and 4 switch models but the logic in the flow chart still applies. Second, be sure your cable to the tv is working and its ends are making good contact, sounds obvious but i have had wires break inside the cable so it works sometimes but not others. Third try turning the power switch on and off several times with the power cord unplugged. I had one junior that would not fire up and cycling the switch must have cleaned the contacts enough to get it going. After this, I would open the system up and try swapping chips (TIA) but with the junior, the chip is not socketed so you can't easily try this. Good luck

 

BAH

[Spirantho]

First place to check is the +5V rail. If that's good, then usually you need to start swapping chips out (hope you know how to use a desoldering tool!).

 

In order of likeliness in my experience:

1) One of the 3 main chips (probably TIA most likely, CPU least)

2) One of the electrolytic caps (these are drying out in all old hardware)

3) the 7805 regulator (if everything has +5V though this is likely fine)

 

 

HOWEVER you say there's no picture at all, so the chips may be good. Even if one of the chips is bad it'll give a black screen at least.

Obviously make sure you're tuned in correctly - check the entire frequency range. If it's a UK Atari it'll be channel 36 UHF, anything else it'll be VHF.

 

Try connecting the TV aerial lead directly to the plug on the board too, rather than the plug in the case.

[Chainclaw]

Didn't get any work done on this today, ended up picking this stuff up instead :

http://www.digitpress.com/forum/showpost.p...mp;postcount=86

 

To keep this from being a meaningless bump, here are some pictures from inside of the JR

 

I took more, my dad taught me to take pictures of every step of disassembling something, so I can actually put it back together when I'm done.

[bones]

You'll probably need to take that metal shield off as well, that's where most of the good stuff is. 2600 jrs. tend to have their main chips soldered directly on the board and not socketed in like the 4 and 6 switch versions. Can make things a bit trickier to replace if one of the chips is dead.

[tremoloman2006]

While you are all on the subject, I have a jr. that comes in fine but the picture "jumps" - it randomly will jitter up a few scanlines just like a TV that doesn't have its vertical hold set properly.

 

This is on a modern TV that my other 2600s and other systems work fine on so I know it's not the TV.

 

Any suggestions on what to check?

[Chainclaw]

Thanks for the info so far guys, I haven't done much more work on figuring this out yet, I attempted to get the shield off but I can't figure it out. Does it have something to do with that orange plastic in the hole in the shield?

 

In better news, I've taken this 3 day weekend (we decided to take Monday off instead of Tuesday) to get some work done on my homebrew project.

[Spirantho]

In better news, I've taken this 3 day weekend (we decided to take Monday off instead of Tuesday) to get some work done on my homebrew project.

 

Good luck! Might take a little longer than a weekend to finish unfortunately. And then you have that Neo Geo homebrew you want to make.

[Chainclaw]

My list of started, but unfinished projects this year alone is through the roof. I've got at least 4 or 5 XNA games, 3 or 4 Atari 2600 homebrews in straight assembly, 2 Batari Basic homebrews sitting unfinished, and untouched in months on my laptop.

And then there are the unstarted projects, like the NEO-GEO, some flash games, and homebrew for every system you can imagine.

 

Even this 2600 Junior repair job is going that direction. I've been poking at it a bit, but have not gotten anywhere. It's clearly not the super-easy problems that I am used to fixing, the kind that just go away with a good cleaning. I was hoping this would be a quick fix, because I have a second Junior I want to fix, a pile of 6-switches, a coleco, and maybe some other stuff.

[Spirantho]

Even this 2600 Junior repair job is going that direction. I've been poking at it a bit, but have not gotten anywhere. It's clearly not the super-easy problems that I am used to fixing, the kind that just go away with a good cleaning. I was hoping this would be a quick fix, because I have a second Junior I want to fix, a pile of 6-switches, a coleco, and maybe some other stuff.

 

Fixing a 2600 is usually a pretty simple job.

First check the +5V line on the chips - if it's not there, check the regulator and the large electrolytic (caps like these usually last about 20-30 years and then weird things happen like voltages disappearing - just fixed my 1050 FDD by changing a cap). That should at least get you onto a black screen on the telly.

[Chainclaw]

I can't figure out how to get the big metal shield off covering most of the board. Any clues?

[shadow460]

If it's similar to that of the 7800, twist the metal tabs until they are straight, then gently lift it off. You might have to pry at it a very little bit. If so, please be careful not to scratch or damage the board.

 

Where's this service manual? I about got owned by a Heavy Sixer today, and a Vader gave me some trouble a while back. Having the manual would have certainly made fixing them both MUCH easier.