Can Someone Make a Repair For Me ?

[Tommy17]

Hello. For starters, thanks for reading this post. I recently purchased a 4-switch 2600 through Ebay. It works well for about 5 minutes, then the screen loses color and the picture gets distorted. From what I read on the messages posted here, my problem should be a bad switch box or a loose RF cable. Well, I've checked both parts and both were found to be ok. That leads me to believe that the RF Modulator is bad. I think I read that someone else had a similar problem.

 

My questions is this - Can someone make the needed repair for me or direct me to a good place that can ?

 

Many thanks in advance.

 

Tommy #17

[darkman]

I am no expert, but I have fixed a Atari 2600 myself. I have also broken a few, then fixed them again. (I have spent more time inside one than I care to say)

 

If I am not mistaken, I think there is a way to adjust the RF signal. I saw somthing inside that you could adjust with a little screw driver... I am guessing that is what it's for. This is just a guess though.

 

If you have allready replaced your cables etc, and it's still a no go, perhaps you should just forget RF alltogether? It's not very difficult to mod your sytem to output video and audio seperatly, just like a modern video game system. If your not confertable with a soldering Iron, etc. I am sure you could find someone to do it for you. I am sure (but not positive) that this would solve your problem. Hell, I could even do it for you. It only costs around $10 in parts. Thakes a little while though. (I am faster, than before, but I am still slow compaired to others I am sure)

 

I know there are places you can mail your Atari, they charge a flat rate of like $25, for repair.

 

-darkman

[Artlover]

I had that problem once.

 

Try replacing the voltage regulator & main capacitor. Thats how I fixed mine. RF circuits tend to be voltage sensitive.

[badbrad]

don't forget to check the power supply.

[Super-Genius!]

I personally think the problem is in the 7805 regulator. From what

you are describing, it gets hot, and does not regulate the 5 volts

properly and that is why you are getting the bad picture.....

 

Take it apart and when it acts up, cool the 7805 with a something

cold, or put a small fan on it just to see if your picture clears up.

 

My money is on the regulator!!

 

Mark

[Tommy17]

I don't even no what the hell I am looking at. LOL.

[Tommy17]

I meant to type "know" instead of "no.

[Tommy17]

Been there, done that.

[Tommy17]

I had that problem once.

 

Try replacing the voltage regulator & main capacitor. Thats how I fixed mine. RF circuits tend to be voltage sensitive.

 

How do I know which is which ? Where could I pick up the replacement parts ? Radio Shack ?

[Tommy17]

I personally think the problem is in the 7805 regulator.  From what

you are describing, it gets hot, and does not regulate the 5 volts

properly and that is why you are getting the bad picture.....

 

Take it apart and when it acts up, cool the 7805 with a something

cold, or put a small fan on it just to see if your picture clears up.

 

My money is on the regulator!!

 

Mark

 

What does the regulator look like ?

[Tommy17]

don't forget to check the power supply.

 

Thanks. I tried that. I couldn't get that lucky to have it be something as simple as that.

[Artlover]

Voltage Regulator is a to-220 case device. It will look like a black square about 3/8" on each side, and 1/8" thick. Will have 3 pins comming out one side. On the opposite side is a aluminum plate with a hole.

 

The power capicator will be the largest one on the board, closest to the regulator.

 

The regulator & capacitor should be on the lower left corner of the board.

 

Radio Shack has the regulator, part number 276-1770. They don't have the exact cap (3200u/16v), but they do have a 4700u/35v that should work ok, part number 272-1022.

[Tommy17]

Voltage Regulator is a to-220 case device. It will look like a black square about 3/8" on each side, and 1/8" thick. Will have 3 pins comming out one side. On the opposite side is a aluminum plate with a hole.  

 

The power capicator will be the largest one on the board, closest to the regulator.  

 

The regulator & capacitor should be on the lower left corner of the board.  

 

Radio Shack has the regulator, part number 276-1770. They don't have the exact cap (3200u/16v), but they do have a 4700u/35v that should work ok, part number 272-1022.

 

Thanks. I'll try and pick up the parts tomorrow. If this doesn't solve the problem, what would the part number be (if you know of course) of the RF modualtor. Or what would I have to do to convert it to the coaxil connection ?

 

Maybe I should have mentioned this earlier. I am going from the console's RF to a gameswitch. The game switch is going to a coaxil adapter. In other words, the twin leads are screwed into one side of the adapter where the other side is a coaxil connection. That part is going to a "tee" (Input from the satellite dish on one end, Atari setup on the other) Could this make a difference ?

[Artlover]

Thanks. I'll try and pick up the parts tomorrow. If this doesn't solve the problem, what would the part number be (if you know of course) of the RF modualtor.  Or what would I have to do to convert it to the coaxil connection ?  

 

Maybe I should have mentioned this earlier. I am going from the console's RF to a gameswitch. The game switch is going to a coaxil adapter. In other words, the twin leads are screwed into one side of the adapter where the other side is a coaxil connection. That part is going to a "tee" (Input from the satellite dish on one end, Atari setup on the other) Could this make a difference ?

 

The RF modulator isn't exactly an off-the-shelf part. Short of taking one out of another unit, I don't know. You could do the composite video/audio mod as an alternative I suppose.

 

As for as how you have it worked up. I'm not exactly sure I understand how you have it hooked up regarding the "T" connector. The switch box should be the last device in line. IE: switch box connected to the TV, and the output of the cable/satellite box goes to the input of the switchbox. You will probably need a coax to spade termianl adaptor (reverse type of adaptor from the screw terminals to coax) to connect to the switchbox.

 

Now, if the satellite reciver has an external RF input jack, you should beable to connect the switch box to that instead of directly to the TV, but again, the switch box would have to connect to that alone, and anything else that used to connect there would need to be attached to the switch box's input.

 

No where should there be a "T" involved regarding the switchbox's output connection.

 

First thing I would do before proceeding, just for the sake of trying it, is connect the switchbox directly to the TV and see if the problem persists.

 

I doubt this is an issue thou because likely, it would have looked like crap from the start, not 5 minutes later. But you should still try reconnecting everything as I suggested just incase maybe there is a RF switching problem with the satellite reciver or something.

[Tommy17]

Voltage Regulator is a to-220 case device. It will look like a black square about 3/8" on each side, and 1/8" thick. Will have 3 pins comming out one side. On the opposite side is a aluminum plate with a hole.  

 

The power capicator will be the largest one on the board, closest to the regulator.  

 

The regulator & capacitor should be on the lower left corner of the board.  

 

Radio Shack has the regulator, part number 276-1770. They don't have the exact cap (3200u/16v), but they do have a 4700u/35v that should work ok, part number 272-1022.

 

IT WORKED !! I replaced the regulator and the console has been working fine. Every once in a while, the screen willget fuzzy for a split second, but it doesn't happen often enough for it to be a problem.

 

I purchased, but have yet to install the capacitor. Will replacing it make any difference now ?

[tearex]

Go ahead and replace the cap, and while you're at it you might want to replace all the electrolytic caps. There's liquid in them and it is not possible to seal them absolutely 100% airtight, so at some point in time they will necessarily dry out enough to stop them from working.

 

But the ones that take most "beating" will go first, and in the Atari those are the main cap near the regulator and the one in the power supply. The others are less critical. You might want to use high temperature caps, especially for the one in the supply, those are built to withstand 105°C / 220°F for extended periods.

[tearex]

One more thing, old electrolytic caps can contain Polychlorated Biphenyles (PCB), quite poisonous and enviromentally hazardous stuff even in small amounts, so they should not ever be burned, it's best to turn them in to the local recycling place.

[Tommy17]

Go ahead and replace the cap, and while you're at it you might want to replace all the electrolytic caps. There's liquid in them and it is not possible to seal them absolutely 100% airtight, so at some point in time they will necessarily dry out enough to stop them from working.

 

But the ones that take most "beating" will go first, and in the Atari those are the main cap near the regulator and the one in the power supply. The others are less critical. You might want to use high temperature caps, especially for the one in the supply, those are built to withstand 105°C / 220°F for extended periods.

 

I am going to change the cap. After a lengthy game of Asteroids last night, the screen went fuzzy again. If the problem continues, I guess I'll take a crack at putting in the composite audio / video.

[Artlover]

Hmmm. Well, replacing the cap wont hurt. It's primary purpose is to filter/smooth out the power from the wall transformer and to provide a momentary source of power if for some reason the wall transform has a drop.

 

However, a bad cap can do odd stuff. Maybe it's discharging in spikes and hurting the regulator. Maybe the wall transformer is passing a lot of AC. Or maybe something downstream from the regulator is going bad, and causing a short.

 

Take a look at the Atari 2600 schematics that are here on AtariAge, and look at the power circuit part (bottom center of the schematic), specificly after the regulator. If this was the case, I would suspect the 4.7u/50v cap or 4050.

 

But lets not get ahead of ourselfs here. Replace the cap, and I'd also suggest getting another regulator and replacing it again too at the same time.

[Tommy17]

Hmmm. Well, replacing the cap wont hurt. It's primary purpose is to filter/smooth out the power from the wall transformer and to provide a momentary source of power if for some reason the wall transform has a drop.

 

However, a bad cap can do odd stuff. Maybe it's discharging in spikes and hurting the regulator. Maybe the wall transformer is passing a lot of AC. Or maybe something downstream from the regulator is going bad, and causing a short.  

 

Take a look at the Atari 2600 schematics that are here on AtariAge, and look at the power circuit part (bottom center of the schematic), specificly after the regulator. If this was the case, I would suspect the 4.7u/50v cap or 4050.  

 

But lets not get ahead of ourselfs here. Replace the cap, and I'd also suggest getting another regulator and replacing it again too at the same time.

 

I can be a little more daring with the repairs being that a 2nd console arrived today. I am going to replace both the regulator and and the capacitor tomorrow and see what happens.

 

If I change those parts and still have the problem, wouldn't by-passing the RF solve the problem ?

[tearex]

If I change those parts and still have the problem, wouldn't by-passing the RF solve the problem ?

 

Maybe. Test the console with the other power supply too - maybe the PS capacitor is not in good shape.

 

If the chips are socketed, you can exchange them between the two consoles and see what happens - but be careful to remember which way 'round they go in there, as sometimes the sockets are soldered in with the marking on the wrong end, so go only by the chips.

 

Before you do the A/V out mod "for good" you can clip some wires to the right places and try if the picture does indeed get better.

[Tommy17]

If I change those parts and still have the problem, wouldn't by-passing the RF solve the problem ?

 

Maybe. Test the console with the other power supply too - maybe the PS capacitor is not in good shape.

 

If the chips are socketed, you can exchange them between the two consoles and see what happens - but be careful to remember which way 'round they go in there, as sometimes the sockets are soldered in with the marking on the wrong end, so go only by the chips.

 

Before you do the A/V out mod "for good" you can clip some wires to the right places and try if the picture does indeed get better.

 

So much for that. I change the cap and the regulator and after about 15 minutes, same problem. I even went as far as eliminating the game switch and using the rca-to-coaxil adapter. Next idea ?

[tearex]

So much for that. I change the cap and the regulator and after about 15 minutes, same problem. I even went as far as eliminating the game switch and using the rca-to-coaxil adapter. Next idea ?

 

Well... no concrete idea here, but basically... when repairing old electronics of any kind... (This might be old news to you)

 

1.) Try different PSUs, different outputs (i.e. another TV set).

 

2.) Replace the electrolytical caps.

 

3.) Refresh or Replace any EPROMs (doesn't apply in this case as there are none in the Atari).

 

4.) Check the solder joints. Do any of them look broken, split, or unusually non-metallic. Resolder those with some fresh solder. "Cold" solder joints are notorious for failing after the device gets warm.

 

5.) Replace the semiconductors. I hope your chips are socketed in both consoles, then those are easy. I sort of suspect the TIA if nothing else has helped so far. Also you can try ice spray - spray the semiconductors one by one. If that makes the problem go away for a while (after a short power cycle to ensure the stuff is reset), then you have found your culprit. Replace. Also you can check with your fingers if anything gets extremely hot. The CPU gets fairly hot even in normal operation though.

 

6.) If so far nothing has helped, you'll have to approach things with a schematic, a multimeter, some understanding, and possibly an oscilloscope. Or just get another console.

 

Sorry if this is not terribly helpful... That's how I'd approach it, it's not a solution but a plan for finding one.

 

I hope your Atari will get well soon.

[Tommy17]

I really appreciate all of the help you have provided for me. Unfortunately, the options I am considering is:

 

1- Sell / trade the unit for 2600 games.

2- Just keep it in storage in case the "good" unit ever needs a part.

3- Pay to have it repaired.

 

I enjoyed changing the the cap and regulator. It was kind of cool getting my hands under the hood. As for the things you would try, well, that is just a little out of my league I think.

[tearex]

Well since there should be enough 2600s to last for a good while from now, I don't see anything wrong with just getting another one.

 

If you pay to have it repaired, just print out the schematics from the AtariAge page and hand them over to the repair guy, that might be enough for some experienced TV/Radio repair guy (preferably old enough to have seen 2600s during their heyday) to find the problem.

 

Have a nice Sunday,