Weird atari 2600 issue, only Frogger works in my console.

[nesmaniac]

Hi everyone. I'm at my wits end here so I thought maybe someone here could help. Frogger is the only game that works in my 2600 4 switch Rev 13. I've cleaned contacts and tested pacman, combat, Ms. Pacman, etc... in other 2600's all work fine. Actually Combat was working but mysteriously stopped. Another time Ms. Pacman worked but stopped and now frogger is all it will play and works everytime. System looks brand new inside and out. I took the 3 IC chips from older six switch atari switching out the TIA first, Then the Riot, and the one closes to cart connector still no dice. I then dug another old Rev 14 4 switch out and confirmed it working and switched each chip out with it until all 3 from it was in the frogger only unit and still frogger only. Does this make any sense? I put 3 chips back in the working Rev 14 and the Color on Frogger and other games is off like in FRogger the area around the edge of the screen is Blue where as it should be green so not sure what's up with that either so now basically I'm trying to figure out 2 different issues with 2 different 2600's. I've reseated the chips a few times and have pretty much ruled them out since I've tried 3 different chips in the system and the other one works with them (albeit color issue) so what the heck gives here?

[Tickled_Pink]

Bloody hell. Never heard of anything like this. Not sure what it could be. I'm not sure about the design of the Frogger cart. Have you tried any other Parker Bros carts? Might be an issue with the cartridge slot itself? Perhaps a problem with the solder joints?

[AlecRob]

Hilarious, tbh lol

[nesmaniac]

Bloody hell. Never heard of anything like this. Not sure what it could be. I'm not sure about the design of the Frogger cart. Have you tried any other Parker Bros carts? Might be an issue with the cartridge slot itself? Perhaps a problem with the solder joints?

 

I have checked the solder joints with continuity tester on each side of all 3 IC chips and all test ok. The cartridge slot pins all look fine as does the solder joints as it's hard to get to those with the tester. I've not tried any other parker bros games any suggestions on ones I might should try that might share something in common with froggers board? If I can figure out froggers pins that are used that would narrow it down a bit. I cannot find anywhere else online of any atari only capable of playing frogger. If I figure it out maybe it would enlighten many to a new troubleshooting solution to other problems.

[Tickled_Pink]

I had a look yesterday and it seems that Frogger isn't bank switched. It's just a 4K ROM. Other 4K games are Jedi Arena, TESB, Amidar, Reactor, Sky Skipper, Q Bert and a few other less common games.

[nesmaniac]

I had a look yesterday and it seems that Frogger isn't bank switched. It's just a 4K ROM. Other 4K games are Jedi Arena, TESB, Amidar, Reactor, Sky Skipper, Q Bert and a few other less common games.

 

Thanks for the info. I have q bert and I think amidar that I will have to try. If they work then definitely onto something.

[nesmaniac]

 

Thanks for the info. I have q bert and I think amidar that I will have to try. If they work then definitely onto something.

 

I tried q bert, amidar, and spiderman non of those work either. Sure has me bummfuzzled. Frogger plays perfect got up to like 1200 points no issue. Other games work fine in other console. Board appears new and atari appears new as well as controllers so I think it had an issue from the start and got put up in the closet and forgotten about until I bought it on ebay 40 years later. What is really strange is at one point it was working other games and at first combat worked no issues but then not even it would work. Ms. Pacman worked temporarily as well but nothing since so I'm thinking it has to be a cap somewhere that all games require to be functioning other than frogger for some reason, or possibly a resistor or transistor I just don't know at this point. I really want to revive this mint atari if at all possible.

[Tickled_Pink]

Replacing the caps would be cheap enough.

If you hadn't already replaced the 3 chips, I'd have guessed the problem to be the RIOT chip in that maybe the other games are writing to memory locations that are faulty. Have you checked the traces and pins around that?

[nesmaniac]

Replacing the caps would be cheap enough.

 

If you hadn't already replaced the 3 chips, I'd have guessed the problem to be the RIOT chip in that maybe the other games are writing to memory locations that are faulty. Have you checked the traces and pins around that?

 

Yeah I checked the edge of each pin going into IC with continuity tester and placed other on bottom chip socket solder and all had continuity and switched out all 3 IC's with others confirmed working in other ataris. I thought for sure that one of those chips would be the logical issue especially considering it worked other games one time but stopped shortly after. It's just really odd and all the caps look fine and I really don't see how cap could be necessary for all these other games other than frogger. As I stated combat was working fine at first it seemed as if when I tried other games it stopped previous working ones from working other than pacman. Next step is to try to find info on how frogger might operate differently than all these other atari carts and go from there.

[Tickled_Pink]

I am leaning towards something having gone wrong somewhere in the circuitry leading up to the RIOT, which may have knocked out some of the internal RAM locations. If the 6507 was faulty, I wouldn't expect it to run anything. If the TIA was faulty then you might have no picture, or a garbled picture. If Frogger only uses a few RAM locations then it might just have gotten lucky. To be honest, though, I'm not sure what would happen if the RAM got knocked out.

 

What are the issues you're getting? Blank screen? Garbled graphics?

[Tickled_Pink]

Another thought. Have you checked the console's switches? When you played the other games, did you flip any of the select switches? Not sure if they're needed in Frogger. Just realised I have a boxed copy of the game at home. If you don't have the manual, I might have.

 

If you did flip a switch, then that could be the problem. The switches seem to connect to the RIOT. You may have a bad switch.

[nesmaniac]

I am leaning towards something having gone wrong somewhere in the circuitry leading up to the RIOT, which may have knocked out some of the internal RAM locations. If the 6507 was faulty, I wouldn't expect it to run anything. If the TIA was faulty then you might have no picture, or a garbled picture. If Frogger only uses a few RAM locations then it might just have gotten lucky. To be honest, though, I'm not sure what would happen if the RAM got knocked out.

 

What are the issues you're getting? Blank screen? Garbled graphics?

 

Most of the time just a black screen but sometimes a screen with audio stuck tune and vertical colored lines usually on the sides. Games fire straight up in another 2600 from same time period even. I hit reset on some of the games trying that after loading them and the black screen shows line of static you know because reset is recognized and working. I'm new to atari repairs but the riot chip is the shortest chip in the middle correct? I know the TIA is the bottom chip that's the first I tried replacing thinking that would fix it. What's the chip closest to the cartridge port I never hear much about it? At any rate I switched all the working chips in another unit to this one still the same and the chips from this one works in the other so I've ruled out the actual chips. Has to be something stupidly simple I would think since frogger plays perfectly fine and especially since it did work the game combat everytime at first and one time it played others as well. That leads me to think something went bad like a diode or cap which for whatever reason frogger don't need. I have to figure frogger's board difference out I think in order to figure out what that game don't need from the motherboard that others do. Thanks for the input every bit is taken into thought that is for sure.

[Tickled_Pink]

The 3 chips are the TIA, the RIOT is the 6532 - that has all the internal RAM of the 2600 (a whole 128 bytes). It handles inputs from the controller ports and the switches. The difficulty, select and Color switches are software controlled, while the Reset switch is hardware controlled. So, if anything was to go wrong with just a few games, the only ones I would think would cause issues is a bad software controlled switch. The other chip is the processor - a 6507. It's a cut-down 6502 that can access a maximum of 8K of RAM or ROM. A normal 6502 can access 64K.

With the cartridge slot at the top, the TIA is at the bottom (possibly marked CO11903, CO10444 or UM6526P1 (PAL) or UM6525 (I think that's the later NTSC part number)). The CPU is the middle chip, probably marked R6507 or CO10745. The RIOT is the one nearest the cartridge slot. That might be marked UM6532, R6532 or CO10750.

Just had a hunt for the field service manual. One was posted here on AA. Maybe it'll give you more ideas: http://atariage.com/forums/topic/238406-atari-2600-field-service-manual/

[nesmaniac]

The 3 chips are the TIA, the RIOT is the 6532 - that has all the internal RAM of the 2600 (a whole 128 bytes). It handles inputs from the controller ports and the switches. The difficulty, select and Color switches are software controlled, while the Reset switch is hardware controlled. So, if anything was to go wrong with just a few games, the only ones I would think would cause issues is a bad software controlled switch. The other chip is the processor - a 6507. It's a cut-down 6502 that can access a maximum of 8K of RAM or ROM. A normal 6502 can access 64K.

 

With the cartridge slot at the top, the TIA is at the bottom (possibly marked CO11903, CO10444 or UM6526P1 (PAL) or UM6525 (I think that's the later NTSC part number)). The CPU is the middle chip, probably marked R6507 or CO10745. The RIOT is the one nearest the cartridge slot. That might be marked UM6532, R6532 or CO10750.

 

Just had a hunt for the field service manual. One was posted here on AA. Maybe it'll give you more ideas: http://atariage.com/forums/topic/238406-atari-2600-field-service-manual/

 

After reading your post I decided to have another look at it. I read about frogger and then that led me to reading about super chip games like Millipede. I thought well if the game has 128K built onboard then it might work and I dug out and cleaned a copy and bingo it works perfectly. So this led me to taking the riot chip out to check it all good and continuity all check ok. I had flashlight looking close at the socket and saw a ceramic disc cap that looked a bit weird like it was swollen at bottom, I then saw that after bending it over it was blown in two. It's to the left of the IC chips and marked .1 z 25T 12V. I've searched all my old parts for that cap and cannot find one. I was reading a post from 3 year ago a guy had the same cap he needed for a 2600 and he could not find one online but someone told him a 0.1 uf cap is the same. I have several cylinder caps so I can probably find one of those but my question is will it work? I don't want to mess anything else up. Do I have to have 12v or will a higher voltage one work like 25v or 50v? I'm hoping this fixes it once I get a replacement.

[+-^CrossBow^-]

Higher voltage is fine. You just need to match the capacitance value and meet or exceed the voltage as the voltage on the caps is a max voltage the cap can handle rating.

[ChildOfCv]

One major difference between the ceramic capacitors and the electrolytic ones is ESR. This is the internal resistance of a capacitor. Ceramic ones tend to have better ESR characteristics for the likely use here: Decoupling. An electrolytic may work in its place, but it's really best to get another .1uF ceramic. They're easy to find and cheap. Here's a link to 25 of them for $6.

 

https://www.amazon.com/Projects-B-0002-C11-Ceramic-Capacitor-0-1uF/dp/B00E6PNOXU/ref=sr_1_5?crid=3NF2PK89FR9F&keywords=1uf+ceramic+capacitor&qid=1554521885&s=gateway&sprefix=.1uf+ceramic%2Caps%2C191&sr=8-5

[nesmaniac]

I replaced the blown .1Z 25T 12V ceramic cap with a 104Z which I read is 0.1 uf and other games would play but pacman, combat, spiderman, etc would still not work. I decided to replace the C201 reset cap which is 4.7 uf and 35v but I did not have anything but 4.7 in 25v so I put it in and tested and finally pacman worked, combat, spiderman, etc...So now my question is should I order a 35v or just stick with the 25v one since all is working? I think I'll replace the other 4.7 because I have another cap but it too is 25v but I believe the one by the RF is lower volt rating anyways. I think that replacing is might clear the picture up a bit what do you all think. Happy I got it working I guess the problem was actually 2 problems which made figuring it out that much more difficult. That blown cap was impossible to see until bending it over so always look close at all caps I guess is the lesson learned here. Thanks for all the information it's been very helpful you all are awesome! May the atari force be with you!

[ChildOfCv]

The system doesn't have any voltages above maybe 9V, so a 25V reset capacitor ought to be plenty good.

[+GoldLeader]

if it was One Day earlier I'd think it was an April Fools day prank haha....

 

It is pretty bizarre.

 

I once had a little portable DVD player w/ a built in screen that would only play one DVD, (True story), The animated version of Animal Farm. It was a cheap eBay purchase and since I used Animal Farm to test it, I assumed it worked. I left positive feedback and so on...And months later I figured out no other DVDs would ever work for some reason.

[nesmaniac]

 

I got her buttoned up and happy to say all working perfectly. Hopefully this might help someone else in the future if by chance (probably 1 in a million) their 2600 only plays frogger. Having a ceramic cap bad and not being able to see it was difficult enough to discover but then after fixing it and still not all games working and discovering another bad cap (reset cap 4.7uf apollo) which appears to be necessary for games like Pac Man to work. After replacing it all worked and for good measure I replaced the 4.7uf apollo that is the RF filtering cap from my understanding. I figured it was probably not going to perform well since the reset one was bad. Only thing is I didn't have a 35V rated cap so I used 25V caps for the 4.7 because I see no harm since system runs off 5V and even tops coming in to the regulator is 11.5 Volts or there abouts. I think atari used 35v because that's what they had and going higher don't matter on the volts. I switched chips out so much thinking it might be a chip seat issue that I think I have chips from a six switch unit in there now on possibly all 3 IC's but it's performing great so I'm not going to mess with switching them out I'll leave them be. I'm just glad to have this beauty resurrected from what would have probably been an atari graveyard. Thanks for all the information guys this site rules.

[Supergun]

Thats truly incredible that you resolved this. I gotta give you credit for not giving up & for being so persistent with it. Ive been there too, myself. Where a problem is just so frustrating that it drives you crazy and it becomes a matter of principal to figure it out.