repair help

[wstankew]

So I bought an atari 2600 4 switch off of ebay last week as a valentines day gift to myself. It finally came in yesterday I hooked it up via coax adapter to my tv but when I plug it in, I get nothing: no black screen, no static, just whatever the ant. is picking up for channel 2 or 3. When I plugged it in initially, I thought I heard a pop followed by some buzzing inside the console. Is it possible that in plugging it in I may have blown out a capacitor or resistor? I have 2 power supplies, one 12v radio shack that I used for years on my old 2600 six-switch, until it finally died, and one that came with the 2600 I just bought that is a no-name 9v universal type deal. The 9v supply is the one that I had hooked up when I first set up the atari (resulting in popping and buzzing). I'm going to pop it open today and look around inside, I guess my main question is if there is anything in particular that I should keep an eye out for?

 

If worst comes to worst, I guess I can always order a NOS board, but I would like to avoid that (the cost in particular).

 

[yorgle]

So I bought an atari 2600 4 switch off of ebay last week as a valentines day gift to myself. It finally came in yesterday I hooked it up via coax adapter to my tv but when I plug it in, I get nothing: no black screen, no static, just whatever the ant. is picking up for channel 2 or 3. When I plugged it in initially, I thought I heard a pop followed by some buzzing inside the console. Is it possible that in plugging it in I may have blown out a capacitor or resistor? I have 2 power supplies, one 12v radio shack that I used for years on my old 2600 six-switch, until it finally died, and one that came with the 2600 I just bought that is a no-name 9v universal type deal. The 9v supply is the one that I had hooked up when I first set up the atari (resulting in popping and buzzing). I'm going to pop it open today and look around inside, I guess my main question is if there is anything in particular that I should keep an eye out for?

 

If worst comes to worst, I guess I can always order a NOS board, but I would like to avoid that (the cost in particular).

 

 

Inspect the power cord connector (on the console pcb) for breaks at the solder joints. Years of plugging and unplugging the cord to the console often cracks these joints.

[wstankew]

well I opened it up and the following things caught my eye:

 

The power plug on the pcb appears to be soldered alright, although it appears that the side of the plug has been removed exposing it's insides

 

The big 2200uF capacitor is dripping something....

 

the solder around one or two of the resistors looks scorched but not too bad

 

The A/V out plug appears to be modified (A new plug/wire soldered straight to the leads on the board instead of plugging in to the on-board plug

 

I think I'm gonna start with the capacitor, because that seems the most out of the ordinary. Any feed back is appreciated

[[d2f]Iggy*SJB]

Sounds like you are on the right track....do us a favor, though.... take pics and let us see what is going on in there.

[A.J. Franzman]

So I bought an atari 2600 4 switch [..] when I plug it in, I get nothing: no black screen, no static, just whatever the ant. is picking up for channel 2 or 3. When I plugged it in initially, I thought I heard a pop followed by some buzzing inside the console. Is it possible that in plugging it in I may have blown out a capacitor or resistor? I have 2 power supplies, one 12v radio shack that I used for years on my old 2600 six-switch, until it finally died, and one that came with the 2600 I just bought that is a no-name 9v universal type deal. The 9v supply is the one that I had hooked up when I first set up the atari (resulting in popping and buzzing).

well I opened it up and the following things caught my eye:

 

The power plug on the pcb appears to be soldered alright, although it appears that the side of the plug has been removed exposing it's insides

It's very common for the clear side panel to fall off. It should work fine without it, though there's a chance that some abuse could cause it to come apart further.

 

 

The big 2200uF capacitor is dripping something...

This is the big clue. Electrolytic capacitors commonly leak or burst if they've been powered in reverse polarity. Combine this with your mention of using a "universal" adapter, and it becomes clear that you most likely had the adapter switch set to the wrong polarity and killed the console. After replacing the capacitor and making sure to have the plug tip positive, you may find that the console works. If it doesn't, the next most likely fried component would be the voltage regulator (generic 7805 or Atari CO10819). This is the part with 3 leads in the lower left corner of the board. If the regulator is bad but replacing it doesn't get the console going, additional diagnosis will be needed, since just about anything could have failed if the reverse unregulated voltage got through to the rest of the board.

 

 

the solder around one or two of the resistors looks scorched but not too bad

This could possibly be flux residue, if the resistors have been replaced or re-soldered for some reason.

 

 

The A/V out plug appears to be modified (A new plug/wire soldered straight to the leads on the board instead of plugging in to the on-board plug

 

I think I'm gonna start with the capacitor, because that seems the most out of the ordinary.

Yup. The RF cable is probably OK as it is; I would leave it alone for now if the soldering looks reasonably competent and there's no obvious damage to the cable. If you get the console working again, then you might consider restoring the correct cable.

[wstankew]

I went out to radio shack and picked up a new capacitor. swapped the old one out, and it still doesn't work... I guess I'm gonna have to make another trip to radio shack and hope they have a voltage regulator

Edited February 16, 2008 by wstankew

[wstankew]

Alright...

 

I have replaced the busted capacitor and the voltage regulator however, I am still getting the same results.

 

This isn't looking good for my Atari

 

Where can I go from here? What's the next most likely failed component?

 

Keeping in mind that I have only basic electronics knowledge, what diagnostic troubleshooting can I do?

[A.J. Franzman]

Well, I would have had you test the original regulator before buying a new one, but since you've replaced it already I think we can rule it out as being bad now.

 

Next question: When you replaced the capacitor, did you make sure to put the new one in, in the same orientation as the original (negative lead to the right)?

 

If so, let's start with the basics: Check the voltages into and out of the regulator. With the console hooked up, cartridge in and power on, carefully test the input voltage between the far pin of the regulator (+) and the middle pin (-) (a.k.a. "ground"). This should be between 7.5 and 15 volts. If it's less than 7.5 but not zero, turn the power switch off and test it at the power jack (on the bottom of the board, the - terminal is nearest to the edge, and the + terminal is farthest from the edge.) You should read between 9 and 16 volts. If not, there's a problem with the adapter, plug or the jack. If your meter shows a negative value with the leads properly placed as I described, your adapter polarity is backwards.

 

If the input voltage is OK, then test the output voltage between the near pin (+) and the middle pin (ground). This should be between 4.75 and 5.25 volts, usually around 4.8 - 4.9. If the output reads low now, since you already replaced the regulator, this would most likely mean that a bad component is shorting out the power. If the output voltage is good but you still get no change on the TV (or maybe just a flicker when you flip the power switch), you could have a bad RF modulator.

Edited February 17, 2008 by A.J. Franzman

[wstankew]

Went out and bought a multimeter today and did some poking around.... I wasn't getting any of the voltages that you were talking about, so I tried switching the Power adaptor and it worked!

 

I can't thank you guys enough for all the help you've given me with this. I'll be sure to stick around the boards and pass the info on to any other atari fans in need

[ninermaniac]

That's what we're here for