Atari 2600 black screen issue

[+-^CrossBow^-]

I usually start cleaning with some 90% or higher isopropyl before moving on to harsher chemicals. I take old credit/debit/gift cards and cut them up to fit the slot width. Wrap around some thick paper (card stock works very well) and soak it with the isopropyl. Then work it in and out of the slot. The card stock is perfect as it's thick enough not to tear when wet, and the surface of it has a little texture to it.

 

If you go the contact cleaner route, just make sure it's safe on plastics and quick drying. That should be noted on the can.

 

I use an old t-shirt wrapped around a cut up fake credit card for this. I do use contact cleaner, but I use a type that isn't electrically conductive and follow it up with the alcohol to help it evaporate quicker. I actually use 99.9% alcohol that I buy at my local electronics hobby shop.

[+RichG1972]

I usually start cleaning with some 90% or higher isopropyl before moving on to harsher chemicals. I take old credit/debit/gift cards and cut them up to fit the slot width. Wrap around some thick paper (card stock works very well) and soak it with the isopropyl. Then work it in and out of the slot. The card stock is perfect as it's thick enough not to tear when wet, and the surface of it has a little texture to it.

 

If you go the contact cleaner route, just make sure it's safe on plastics and quick drying. That should be noted on the can.

The contact cleaner I advised them to use says it right on the can, 3rd line down on the label "Harmless to most plastics", plus no residue either and it is not necessary to use alcohol afterward because that will just dilute the protective barrier that is put in place with this particular cleaner

 

 

[ChildOfCv]

Sorry for the long delay, I just got the chance to do these tests. I assume the voltages on the address and data pins are measured against the unit's ground (if not, then please ignore these results and correct me).

 

After the unit is powered on, the address and data pins on the CPU have a variety of different voltages, but each pin remains at a certain voltage, with only the occasional 0.01V variation up or down. After the unit has been on for a few minutes, the voltages suddenly change: all of the address pins are at 3.2V, and all of the data pins are at 0.02V. I did these tests with a cartridge in the slot, although I doubt it will be different without one.

 

Any thoughts or ideas are much appreciated!

That does sound like the CPU might be alive. But apparently nothing is driving the data lines. It may be that the address line that activates a cartridge read is not making contact. The most likely culprit is A12 (pin 18 on the cartridge connector). You could remove the plastic keying bezel thing from the cartridge connector and take a close look at the pins for corrosion or liquid damage. Just make sure to take note of its orientation so you don't get it wrong when you put it back.

[d_a_parker]

I have cleaned the cartridge slot, but unfortunately the issue persists. I even tested each pin in the connector for continuity with the corresponding pin on the bottom of the board, and they were all fine. So it looks like the cartridge slot is okay.

 

I'm starting to suspect it may be easier to just buy another 2600. I'd love to get this one working again, though. I was just hoping it wouldn't come down to replacing one of the soldered-on ICs.

[d_a_parker]

Interestingly, different cartridges cause different things to be displayed. Some cause a solud black screen, others cause a black screen with some "snow" in it, and a few cause a fairly snowy black screen. Each cartridge is pretty consistent.