47 replies to this topic

[A-T-A-R-I]

Hi all,
    I came upon this forum and hope someone can help. I was lucky to acquire 3 Ataris the past weekend at a flea market. They all power up and have pictures, but each has an issue.

Unit 1
Atari 2600 4 switch
This works correctly, but has no color whatsover. I checked the color switch, also have read about the color wheel on other posts and tried that turning both ways, and no change.

Unit 2
Atari 2600 4 switch
Unit works, but has no audio output, but a bunch of white noise. The color or screen is not too bright either.

Unit 3
Atari 2600 4 switch
Unit works, but when it is on and sitting in "standby", the screen starts to get a lot of interference or something. Almost like thumbprint swirls all over the screen. If you turn it off and back on, it is normal until you let it sit for awhile in standby. I tried resoldering everything, but still does it.

Any help is needed. Thanks.

Edited by A-T-A-R-I, Tue Dec 8, 2009 2:41 PM.

[A-T-A-R-I]

Anybody have ideas?

[A-T-A-R-I]

So I guess everyone on here just buys but doesn't fix?

[Kurisu]

Odds are no one even begins to have solid answers, and instead of waste your time with non-helpful posts, they just move on, as I did originally.

I have tried to use my limited knowledge to address your situations, but I have no ideas that you have not already tried. :/ sorry.

[atari_envy]

A-T-A-R-I, on Wed Dec 9, 2009 11:17 PM, said:

So I guess everyone on here just buys but doesn't fix?

Sorry, but yes, that is what I do.  There are still so many inexpensive units out there still that I just buy another one.  I have sent several non-working units to the great ET Landfill in the sky.

[potatohead]

I will fix, but I don't have a good handle on the problems you have.  

The audio makes me think a capacitor has gone bad.

The one with no color makes me think of a broken circuit trace, or bad cap as well.

Need to take a scope, or something and follow the color signal from it's source to the output and see where it goes away.  If there is no color at the chip source, then it's a bad chip.  Replace it.  Follow along the circuit traces until you don't see it anymore, replacing things as you find gaps.

That's my usual approach, but it doesn't work well over the net.

[A-T-A-R-I]

Thanks for the replies. Wanted to show some pics of what is happening.
First pic is the normal screen while in "standby" mode, which is perfect.


Now, after you let it sit for awhile (no playing) while in standby, it starts to do this;



You can see where it starts to have interference, almost like a thumbprint pattern, swirly/rf pattern, not snowy.
I switched all three chips with new ones, resodered all the areas on the back of the board, and still does it. Now if you turn it off and back on, all is good for another 4 mins or so.

Doesn't seem to do it while in play mode, just standby. Any ideas? Someone emailed me and said something about replacing the 35v electrolytic capacitator near the modulator, but I have no idea what that is.

Edited by A-T-A-R-I, Thu Dec 10, 2009 3:40 AM.

[A-T-A-R-I]

potatohead, on Thu Dec 10, 2009 12:21 AM, said:

I will fix, but I don't have a good handle on the problems you have.

The audio makes me think a capacitor has gone bad.

I REPLACED THE TWO CLEAR CAPACITORS THAT ARE SUPPOSEDLY FOR THE AUDIO, BUT STILL NO GOOD

The one with no color makes me think of a broken circuit trace, or bad cap as well.

Need to take a scope, or something and follow the color signal from it's source to the output and see where it goes away. If there is no color at the chip source, then it's a bad chip. Replace it. Follow along the circuit traces until you don't see it anymore, replacing things as you find gaps.

I REPLACED ALL THREE CHIPS WITH NEW ONES, STILL NO COLOR. I DON'T HAVE A SCOPE, IS THERE ANY OTHER WAY TO TRACE THE COLOR SOURCE?

That's my usual approach, but it doesn't work well over the net.

THANKS FOR YOUR HELP

[potatohead]

It looks like a little can.  See big ass link below, or put "electrolytic capacitor" into google images.


http://images.google...:en-US:official

It will say "35v" on it.

Replacing this is pretty easy actually.  First, you need to locate the thing.  Then you need to note how it's mounted on the board.  It has polarity, so the new one has to go in the same way, or there will be trouble.  There is a bold marking on the can, denoting the positive lead.

The "modulator" is a metal can, shiny.  This capacitor will be near that can.  I don't have a 4 switcher, so that's gonna limit things.  Maybe somebody has a picture...

You then gotta go get another one.  Maybe Radio Shack, one of the other Ataris, your surplus store, or....  

To remove it, either heat both solder joints, while pulling on the component to remove, or use a desoldering tool to suck away solder from a warm joint, then use light heat to remove.

Don't keep the iron on the board for any real length of time, and don't use a really hot iron.  The circuit traces are fragile and peel away really easy.

If it were me, I would practice on some other electronics thing that you don't care about first to get the hang of this.  Somebody has a radio, or something they don't need right?  That's your baby.

Good luck!

Edit: In my quoted post above, I wrote "I will fix, but don't have a good handle..."  What I meant by that is I will generally fix my Atari stuff because I don't mind doing it, or the time doing it, not that I will fix your Atari!

Just wanted to be clear on that.  Not that I mind giving some info that might help.  I just can't own fixing your machine, that's all.

Edited by potatohead, Thu Dec 10, 2009 11:17 AM.

[A-T-A-R-I]

Thanks for the reply Potato. I changed the electrolytic "tin can" cap and no change, still the same problem

[A-T-A-R-I]

Anyone have any more ideas I can try?

[brojamfootball]

For the 2600 with screen issues:

Looks like an issue with corrosion/oxidation on a connector somewhere to me.  I've seen this stuff many times.  The signal can make it through at first, but fades after a while.  Try cleaning all the RCA-shaped connectors(and the RF jack on the TV), all the way from inside the Atari to the TV.  Sandpaper, wirebrush, emery board, q-tip and alcohol, whatever you have.  

Quick pre-test may be to jiggle and twist all connectors in the signal path while you're having the issue.  Even try putting a little gentle pressure on the jack on the back of the TV.

You want a nice clean, shiny surface on everything:  the jack inside the Atari, jacks on your cords, even the jack on the TV.  Have you tried this on another television?  The TV's connector may have bad solder joints as well.  

Is the unit going direct to the TV's RF jack?  Switchboxes are notorious for all kinds of issues like that, if you're using one.  I made a direct connector by chopping the female end off an RCA extension cord I had and twisting the wires together with an old 75ohm cable I had lying around, but you can buy one as well.

That's what it really looks like is your issue to me.  Try changing out every wire in the signal path also.

Edited by brojamfootball, Fri Dec 11, 2009 7:15 PM.

[tz101]

Unit 1: Replace the color/bw toggle switch on the board. I have had these switches go out on more than one 2600 console. If new switches are not available at Radio Shack or an electronics dealer near you, then you will need a donor system, maybe unit 2?

Unit 2: Noise is due to a problematic sound processor. Is this a separate chip that can be replaced? I am not in the know on that, as I mainly have heavy sixer consoles at present.

Unit 3: This is a problem with the RF modulator. Begin by resetting all the solder points on this unit. If that doesn't do it, may need to replace the RF output jack itself. Again, Radio Shack or a donor system.

Hope this is somewhat helpful.

[A-T-A-R-I]

brojamfootball, on Fri Dec 11, 2009 7:12 PM, said:

For the 2600 with screen issues:

Looks like an issue with corrosion/oxidation on a connector somewhere to me;

Thanks for the help. I cleaned the RCA connection, although it looks like new and is shiny. I am using the regular cord from the unt to the tv with a RCA/f Type connector. I changed cords, tvs, etc, and same issue. It seems when the unit heats up for awhile is when the issue starts. I also resodered everything, so there can't be any bad connections.

[A-T-A-R-I]

tz101, on Fri Dec 11, 2009 7:15 PM, said:

Unit 1: Replace the color/bw toggle switch on the board. I have had these switches go out on more than one 2600 console. If new switches are not available at Radio Shack or an electronics dealer near you, then you will need a donor system, maybe unit 2?

Unit 2: Noise is due to a problematic sound processor. Is this a separate chip that can be replaced? I am not in the know on that, as I mainly have heavy sixer consoles at present.

Unit 3: This is a problem with the RF modulator. Begin by resetting all the solder points on this unit. If that doesn't do it, may need to replace the RF output jack itself. Again, Radio Shack or a donor system.

Hope this is somewhat helpful.

*Thanks for the help. My friend had an old unit that he gave me to use for parts, so I took a switch out of that and put it in unit . No change whatsoever.

*Your guess is as good as mine. There are 3 chips on this board, but I changed them all, and no difference.

*I did resoder everything on the board, but now switched the rf output jack, but still having the same problem.

I am about ready to beat my head on the table. It is just frustrating being they all work, but have a flaw in each, and they are all in nice shape.

[shadow460]

A few ideas from a redneck hillbilly:

Are you running any kind of switchbox on unit 3?  I didn't see one mentioned.  Usually when I have the grainy picture it's the switchbox wanting to act up.  You might also open that RF box again.  It may have gotten something in there or the board might be touching the shield and grounding.  If you didn't solder the shield back to the mainboard, go ahead and do that.

On unit 1, you might try a game that doesn't have a B/W mode, like Starmaster.  If there's something up with the circuit on the TV Type switch, it may get stuck one one screen or the other, or just freak out.  If Starmaster turns black and white, though, it's definitely not the TV type switch or anything hooked to it.

Some of the first units made had faulty cartridge ports.  Mine does, but the port has not failed yet.  You might have to change the port.

Sounds like it's going to require some component level troubleshooting, though.  They're fixable, even though it might be difficult.

What type of solder did you use?  That's one common denominator in anything you have reflowed.

[potatohead]

If it's heat related, maybe applying some heat can isolate the problem.

So toss the one in the deep freeze, as a control, then bring it out and fire it up.  Note the time to failure.

Get a hair dryer, and fabricate a plenum to direct the air in a small region.

Repeat in different areas, applying the heat to get to the failure more quickly.

?!?

[A-T-A-R-I]

shadow460, on Fri Dec 11, 2009 10:43 PM, said:

A few ideas from a redneck hillbilly:

Are you running any kind of switchbox on unit 3? I didn't see one mentioned. Usually when I have the grainy picture it's the switchbox wanting to act up. You might also open that RF box again. It may have gotten something in there or the board might be touching the shield and grounding. If you didn't solder the shield back to the mainboard, go ahead and do that.

On unit 1, you might try a game that doesn't have a B/W mode, like Starmaster. If there's something up with the circuit on the TV Type switch, it may get stuck one one screen or the other, or just freak out. If Starmaster turns black and white, though, it's definitely not the TV type switch or anything hooked to it.

Some of the first units made had faulty cartridge ports. Mine does, but the port has not failed yet. You might have to change the port.

Sounds like it's going to require some component level troubleshooting, though. They're fixable, even though it might be difficult.

What type of solder did you use? That's one common denominator in anything you have reflowed.

No switchbox, wire direct to rca/f type connector

I tried Starmaster, it stayed b/w either way on the color/b/w switch, BUT if I turned it on in the B/w mode and switch to color, the screen did go nuts, same if I turned it on in color and switched to B/W it also went nuts. The top of the screen froze and instead of two rows of numbers at the bottom, there were 4 rows.

I have been using rosin core solder.

[A-T-A-R-I]

Any other ideas? I really hate throwing these away since I have waited so long to find some at a good price.

[seanhq]

A-T-A-R-I, on Mon Dec 14, 2009 1:01 AM, said:

Any other ideas? I really hate throwing these away since I have waited so long to find some at a good price.

My suggestion is based on the amount of time you've already put into trying to fix these units, you might want to just pick up a working unit from someone here via the AtariAge marketplace. If all you're concerned with is a working Atari 2600, you should be able to pick up a working unit with controllers, games, etc for around $40.00 USD or maybe even less.

By doing that you will have a nice working unit, then in your spare time you can continue to beat on the other non working/partially working machines or use them for parts if/when the unit you get from an AA member starts to have issues.

[RevEng]

I agree he could buy new ones and save time, but why not try to bring a few back from the brink? One or two more Atari's in the world is a good thing.

potatohead, on Fri Dec 11, 2009 11:12 PM, said:

If it's heat related, maybe applying some heat can isolate the problem.

So toss the one in the deep freeze, as a control, then bring it out and fire it up.  Note the time to failure.

This is a very good suggestion. Did you try it out A-T-A-R-I?

Change in behaviour after warm-up usually means mechanical break... Bad solder, hairline crack in board, cracked resistor, cap seperated from lead, etc. Many of these can hard to spot, but the freezer thing will confirm if you really need to start hunting.

Regarding the B&W one, in order of difficulty...
1. Make sure its not a PAL 2600. These will show up without colour on many NTSC TVs.
2. Swap out the colorburst crystal.
3. Swap out the TIA

Good hunting!

Edited by RevEng, Mon Dec 14, 2009 5:39 AM.

[A-T-A-R-I]

RevEng, on Mon Dec 14, 2009 5:32 AM, said:

I agree he could buy new ones and save time, but why not try to bring a few back from the brink? One or two more Atari's in the world is a good thing.

This is a very good suggestion. Did you try it out A-T-A-R-I?

Change in behaviour after warm-up usually means mechanical break... Bad solder, hairline crack in board, cracked resistor, cap seperated from lead, etc. Many of these can hard to spot, but the freezer thing will confirm if you really need to start hunting.

Regarding the B&W one, in order of difficulty...
1. Make sure its not a PAL 2600. These will show up without colour on many NTSC TVs.
2. Swap out the colorburst crystal.
3. Swap out the TIA

Good hunting!

Not a PAL
I swapped out the colorburst crystal, no change.
Changed TIA to known working chip, no change.

I resoldered the entire board, but no change, still does it. I threw it in the freezer for about a half hour, powered it up, and it started the interference about the same time as usual.

Any other ideas? Thanks

[RevEng]

Wow, these are some tough nuts to crack!

The B&W Unit...
Looking to the 2600A schematic, it's either a problem from the colorburst circuits leading to TIA's pin 11, or the circuits that take the chrominance out from TIA's pin 9.

You don't have access to a scope, but multimeters with frequency counters are pretty cheap, and you can see if the actual colorburst input is being generated. In any case, break out a multimeter and check the involved resistors in those areas and make sure the caps read open, as small caps should.

Its weird that switching the color/b&w switch makes the screen go nuts... this switch doesn't differ from the difficulty or select and reset. All of them are attached to the 6532 and just acted on in software. Does switching the difficulty make the screen go nuts too?

The Swirly Unit...
Re-reading your original posts, this problem only happens in "standby mode"? That's pretty weird too - there isn't a "standby mode" built into the 2600, its just something that some games implement. Maybe it's certain color combinations that are highlighting a problem with the RF modulator... you might try swapping RF cables or doin a composite mod.

[A-T-A-R-I]

RevEng, on Wed Dec 16, 2009 7:13 PM, said:

Does switching the difficulty make the screen go nuts too?

there isn't a "standby mode" built into the 2600, its just something that some games implement. Maybe it's certain color combinations that are highlighting a problem with the RF modulator

Thanks for the reply.
Nope, just when switching from B/W to color or vice versa.
I call it standby. It is actually when the game is on but not being played or hasn't been reset, the screen shows the game while switching various color palettes. Warmup mode??

[pacman100000]

good stuff