Atari 5200 Red screens

[Tigg]

Hope you knowledgeable folks could help lead me in the correct direction. 

I was given 2 Atari 5200 4 port consoles, complete systems neither had the ac/rf switch require for the 4 ports.

 

I purchased an Atari brand switch  (new/old stock) and 1 I got a green screen with or without a cart inserted

The second would have a black screen with a whining sound with out a cart, with a cart it would have what looked like code, or an alien language lol symbols and numbers scrolling the screen rapidly.

 

Purchased a 4 port rf mod kit from brewing academy and an Ac mod from consoles.

Got everything installed and now both give me a red screen with or without carts.

 

I apologize for the lengthy description but wanted to give as much information as I possibly could. Hope someone can lead me to the proper direction so I can enjoy reliving my

 childhood memories. 

Thanks

Tigg

 

 

[+-^CrossBow^-]

Can you provide some pics of the work you have done on them? Also do you happen to have any pics of what the screens looked like before any of the work was done on them?

 

The corrupted characters one sounds like possible a bad RAM chip. The green screen only issue is something I would have to research a bit, but that could just be due to the system not being able to read a cartridge properly due to dirty, corroded, or bent/misaligned contacts inside the cartridge slot?

 

[Tigg]

On 6/1/2022 at 11:07 AM, -^CrossBow^- said:

Can you provide some pics of the work you have done on them? Also do you happen to have any pics of what the screens looked like before any of the work was done on them?

 

The corrupted characters one sounds like possible a bad RAM chip. The green screen only issue is something I would have to research a bit, but that could just be due to the system not being able to read a cartridge properly due to dirty, corroded, or bent/misaligned contacts inside the cartridge slot?

 

apologize for the delayed response, I have been in Chicago for the week. I dont have any pics of the before, but here is the work I have done, including power which hasnt given me an issue.

[+-^CrossBow^-]

1st... did you remove the 4050? If you did, I'd suggest putting it back into circuit in some way and see if it changes anything.

2nd... you should be taking your audio from the top of R50..not the bottom of it. Taking it from the bottom is really no different than taking it directly off the POKEY and the audio even from the top of R50 is still too to hot a signal. I actually add another 2k resistor and 10µf cap in series from off of R50 before wiring it to the RCAs.

[Tigg]

On 6/7/2022 at 3:58 PM, -^CrossBow^- said:

1st... did you remove the 4050? If you did, I'd suggest putting it back into circuit in some way and see if it changes anything.

2nd... you should be taking your audio from the top of R50..not the bottom of it. Taking it from the bottom is really no different than taking it directly off the POKEY and the audio even from the top of R50 is still too to hot a signal. I actually add another 2k resistor and 10µf cap in series from off of R50 before wiring it to the RCAs.

So sorry, I thought I replied to this but I guess the wifi in my motel in Chicago was pretty crappy.
1- the 4050 is still in place, I soldered the UAV to it. 

2- I just followed some installation videos I had seen, but thanks for the info on the R50 I will get it moved. Also, I don't think you can see through the pictures, the red wire coming for the R50 has an area that is wrapped in electrical tape, it contains a 10µf cap and 2k resistor. should I add another set? (only reason it's taped is because I didn't have any heat shrink large enough to fit over the Cap)

Thanks again for your help, hope I can figure this one out

[+-^CrossBow^-]

No..you don't need to any other components just move it to the top of R50 and you should be good. It will still likely be louder than other consoles you have connected but shouldn't distort as it can without those components.

 

Okay...so you have the 4050 in place and the UAV soldered onto it. Did you solder the socket ontop of the 4050? If so... then remove the UAV and see what you get through RF at that point?

[Tigg]

32 minutes ago, -^CrossBow^- said:

No..you don't need to any other components just move it to the top of R50 and you should be good. It will still likely be louder than other consoles you have connected but shouldn't distort as it can without those components.

 

Okay...so you have the 4050 in place and the UAV soldered onto it. Did you solder the socket ontop of the 4050? If so... then remove the UAV and see what you get through RF at that point?

Might be an issue if you want me to use the cable that came with the Atari, as I removed it as all the videos I watched stated to do  O did go ahead and try with the UAV out of the socket and of course got nothing at all... tv didn't even get a signal

[+-^CrossBow^-]

Must not be the video I did then as I keep the RF fully intact and working as a backup for troubleshooting. Even with the power conversion, you don't actually have to remove the cable. It can stay soldered up and will still work for RF output.

 

Speaking of...you see that RCA jack near where your desoldered the cable? That still works too so you could connect up another piece of coax from there like from a 2600 or other console if you have one to see if you get anything.

 

 

 

[Tigg]

I don't have a n extra coaxial, but tried a rca cable just hoping lol. I am going to keep looking around for a cable to try. I did have another 4050 chip so I sat it in the original socket an loosely put the UAV on top touching prongs and got the following results

 

Edited June 12, 2022 by Tigg

[Tigg]

Update: I found a coaxial from an old ColecoVision, and here are the results

[+-^CrossBow^-]

I might have missed it if you said it before... but was this console working prior to any of the upgrades being performed?

 

At this point, it might be worth it to pop the main IC chips out one at a time. Inspect the legs of the ICs for any possible corrosion and clean them up if you can. Inspect the sockets as well. That board looks a bit crusty so it is quite possible one of more of the ICs isn't making proper connection. I would start with possibly the CPU which in your above picture of the q-bert cart is the IC just below left of the cartridge slot there.

 

 

[+x=usr(1536)]

On 6/16/2022 at 8:52 AM, -^CrossBow^- said:

I might have missed it if you said it before... but was this console working prior to any of the upgrades being performed?

 

At this point, it might be worth it to pop the main IC chips out one at a time. Inspect the legs of the ICs for any possible corrosion and clean them up if you can. Inspect the sockets as well. That board looks a bit crusty so it is quite possible one of more of the ICs isn't making proper connection. I would start with possibly the CPU which in your above picture of the q-bert cart is the IC just below left of the cartridge slot there.

 

Everything -^Crossbow^- wrote above is advice worth following.

 

One of my 2-port 5200s had a bad CPU.  There were two symptoms it displayed: one, locking up after approximately 6.5 minutes of running regardless of the cartridge inserted; two, crashing immediately to a red or green screen at boot after the CPU had overheated and not been allowed to cool down.  The CPU was much hotter than the other ICs when this happened, and swapping it out with a known-good one solved the problem.

 

Also, since you're working on a 4-port console: there was a batch of known-problematic Rockwell CPUs that had timing problems.  These were 'fixed' by Tech Tip #7 (attached), released by Atari after the bad CPUs were out in the field.  Probably worth looking into as the modification could have become damaged, etc. if yours had had the fix.  Having said that, if the CPU is bad or needs the fix, my suggestion would be to just replace it with a Synertek-manufactured one; they've generally been reliable.

 

 

Tech.Tip.07.pdf

[+-^CrossBow^-]

1 hour ago, x=usr(1536) said:

 

Everything -^Crossbow^- wrote above is advice worth following.

 

One of my 2-port 5200s had a bad CPU.  There were two symptoms it displayed: one, locking up after approximately 6.5 minutes of running regardless of the cartridge inserted; two, crashing immediately to a red or green screen at boot after the CPU had overheated and not been allowed to cool down.  The CPU was much hotter than the other ICs when this happened, and swapping it out with a known-good one solved the problem.

 

Also, since you're working on a 4-port console: there was a batch of known-problematic Rockwell CPUs that had timing problems.  These were 'fixed' by Tech Tip #7 (attached), released by Atari after the bad CPUs were out in the field.  Probably worth looking into as the modification could have become damaged, etc. if yours had had the fix.  Having said that, if the CPU is bad or needs the fix, my suggestion would be to just replace it with a Synertek-manufactured one; they've generally been reliable.

 

 

Tech.Tip.07.pdf 319.62 kB · 1 download

That is why I told him to start withe CPU first hehe...

 

It is also worth noting that quite a few of the 5200s with that Rockwell chip had the modification done by Atari. They installed it in a pretty convoluted way on the top component side to the left center of the board off one of the 74x logic chips. So if you seem some resistors etc. looking hand hammered onto a chip there, that is likely the fix already in place. I think the method they list on the bottom of the PCB is a simpler and better looking fix to the issue.

 

Also, not having that fix doesn't prevent the games from working. It just causes timing issues with the graphics on quite a few games making them not look quite right as was demoed in that video.