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.

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.

Thanks, but I already tried following that flow chart and found that without an oscilloscope, it's not easy. Everything seemed to be ok when measuring voltages with the multimeter, though. I'm going to try cleaning the cartridge slot again. Does anyone have experience with the WD-40 Specialist Contact Cleaner available at Home Depot?

That's a good point about the cartridge slot. I sprayed it with a can of air and cleaned it as best I could with 91% isopropyl and cotton swabs, but it's a very narrow opening and I don't think I really did much. I'll try to get some contact cleaner that I can spray right in there. It was plugged into a CRT each time I used it, and that's what I'm testing with now. Thanks!

I have tested 5 cartridges at random, with the same results every time (black screen). I did not change cartridges during my tests when I measured the address and data lines, though.

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!

The RIOT chip was the prime suspect in the other thread, but the OP said that it turned out to be the CPU. They did not say how they traced it to the CPU, but in their case the chips were in sockets, so it's possible they just swapped them out until it worked. It's an awful lot of de-soldering/re-soldering for me to go that route, so I was hoping to track down the problematic component before starting any physical work on the board. The board does not seem to have any water damage, bug damage, or corrosion. But the traces are bubbled up. I have found a few posts online (such as this one) which indicate that bubbled traces are not uncommon in systems of that era, and generally do not cause functional problems unless there is also corrosion. That doesn't mean they're not the problem here, but this thing worked a few years ago and I doubt the bubbling is new since then. Thanks!

I just realized that my multimeter only measures up to 20 KHz (not 20 MHz), so I think the problem here is that the clock frequency on the 2600 is out of range. I need to get a scope. But the voltage on the various clock points seems fine (it's not a solid 0V or 5V). Assuming the clock is okay, what else could it be? The ICs all have good voltage going to them, the voltage regulator is working fine, and the switches are clean. Could one of the chips have gone bad? Thanks!

Unfortunately, I don't have access to an oscilloscope right now so I can't do the proper checks on this thing. I have a multimeter with a frequency setting, though. When testing these points for voltage I get a non-zero reading somewhere between 1v and 2v. When I test for frequency, I get a seemingly random value each time, which quickly falls to zero within a few seconds. Any thoughts or ideas on where to go from here are much appreciated. I'm going to try to borrow a scope next week if possible, but I'm not sure I'll be able to. Thanks!

Thanks! I didn't know that, but now it makes a lot more sense. Unfortunately, I don't have an oscilloscope to check this with. Dang.

I found the correct service manual, and followed through the "Black or Solid Colored Screen Troubleshooting" flow chart (J). I got as far as this step: Is 4-5v p-p osc. signal present on pin 11 A201? That's the OSC pin on the TIA, and I only have 1.5V on that pin when measured with a multimeter. So if the answer is "no" then the flow chart goes on to say: Open between C203 and pin 11 A201. Which leads to: Repair I'm afraid I don't know what an "open between C203 and pin 11 A201" means, nor do I know how to repair it. Does anyone have any advice? Thanks!

Thank you for the information. I tested the chips and they seem fine, as far as I can tell: Vcc is ~5V on each chip Vss has continuity to ground on each chip Reset is ~5V on the CPU and RIOT (I didn't see a reset pin in the diagrams I found for the TIA) Clock is ~1.8V on the RIOT (I didn't see a clock pin in the diagrams I found for the TIA and CPU) (EDIT: I missed the fact that the TIA does have an OSC pin, which is holding at ~1.5V) Based on these simple tests, it looks like the correct voltages are getting to the ICs. Is there something else I can check? I looked for the service manual, but I only found the one for the six-switch VCS with an earlier board revision. Does anyone know if there is one available for the later model 2600 with the rev. 16 board? Thanks!

Hello, I have a later-model Atari 2600 "Darth Vader" with a rev. 16 board. It worked fine a few years ago. But now when I power it on, with or without a cartridge, I just get a blank screen with a colored line down each side. It's a similar problem to the one posted here, but on a different model 2600: http://atariage.com/forums/topic/207387-broken-atari-2600-with-black-screen/ I checked the voltage regulator and it has ~9V in and ~5V out, so that seems fine. The power switch looked fine, but I cleaned it anyway. I also cleaned the contacts in the cartridge slot as best I could. I checked the three main chips (TIA, CPU, and RIOT) and none of them feel hot while the unit is powered on. Unfortunately, the chips are soldered onto the board instead of in sockets, so it's not a simple task to swap them out. With that in mind, is there anything else I can check and/or do to try and fix this system? I've never worked on a 2600 before, so I'm not exactly sure where to go from here. And if it's dead, I'll just need to be ok with that. :-) Thanks!

Yep! It certainly seems my old board is defective, because the DuoDisk is working correctly with the new one. Some of the chips on the old board are in sockets, so I may try swapping those out if I come across any replacements. Thanks!

Thanks! If shipping is cheap enough I will certainly take that deal. Can you PM me and we can figure it out?