How commonly do old caps cause snow on a 2600 Jr?

[sethbramwell]

Hi All,

 

I recently picked up a 2600 Jr and cleaned it inside and out. I am able to connect it to both my modern LCD TV and a 1970's era CRT, but there is some snow on both TVs. It's slightly worse on the older TV, but I suspect this is due to the fact that it only has screw terminals (no built in coax input) and I have to use an adapter with the RCA to coax adapter.

 

On the modern TV, I can mess with the RF cord (using a single component video cable as it's yielded the best results of any I've tried) and the picture will come in without snow, but only if I hold it. I already checked the RF jack inside and it does not appear to be loose.

 

Research has led me to suspect that it is due to the old capacitors, but I wanted to ask if anyone knew how common it is for them to cause snow on the screen. I ordered a cap kit and will recap regardless, but I want to know (if possible) the likelihood that the caps are the culprit.

 

Thanks!

[ChildOfCv]

If holding the cord in place gets you a good picture, it is almost certain to be the RCA connector. Of course it can always be the connection on the cable side too. My old NES had a loose wire at the console connection.

[sethbramwell]

Strange thing is it only does that on the modern tv. I was wondering if it was due to the better picture tech.

[+LS650]

I own several old 2600s. Never had to recap any of them.

[sethbramwell]

Also wondering just because it's a junior. Cheaper model, cheaper parts I'm guessing...

[ChildOfCv]

You can see a picture of the board with its RCA connector on the upper right here:

 

http://atariage.com/forums/uploads/monthly_01_2016/post-44560-0-74119900-1452563870.jpg

 

Commonly, what happens with this type of connector is that the barrel, which is merely pressed into the frame like a rivet, begins to loosen. The solder connections might still be holding, but since the barrel sits loose in the grounding frame it can still lose connection. The other possibility is that the spring contact for the middle pin has weakened and can't make good enough contact. By proximity it can still get a little bit of signal through, so you get a snowy picture and not just static.

 

This happens on a lot of well-used devices, not just the cheap ones. The only real fix is to replace the connector.

Edited April 4, 2019 by ChildOfCv

[sethbramwell]

Thank you for explaining that! I believe I have a new RCA Jack coming with the cap kit. I think I'll replace that first and see where it gets me.

 

What is the resistor that's circled in the picture? Anything critical to the picture?

Edited April 5, 2019 by sethbramwell

[ChildOfCv]

Yeah that picture was from another thread where the OP asked the same question

 

Most likely it's actually a capacitor. Atari had a weird habit of making multiple component types look alike, and you'll notice other components of the same shade of puke that are marked as C## instead of R##, while the resistors have a more tan color. The color code seems to say 15pF.

[imstarryeyed]

I have fixed over 100 Atari Jr's and most of the time:

 

1) RCA Cable is not thick enough for a great picture, the original one often gets old or lost and gets replaced by a thin un-shielded cable. Get a cable that is thick and has a thick inner cable and thick shielding.

2) RCA cable needs to be cleaned, clean that center pin and the prongs inside and out. Try a steel wool brush that is about as big as a toothbrush, look for those at a hardware store.

3) RCA Jack needs to be cleaned on the outside and inside, a real pain, use contact cleaner and a pick to scrape away dirt on the inside.

 

In cleaning those RCA parts you are really looking for a shinier shine than what you most likely have after years of use.

 

I found that cleaning those parts and / or getting a suitable RCA cable is important.

 

I have also had very good results adding an RF Choke snap on to the RCA cable end.

 

All three of those work well for me for RCA systems.

 

I have never had to change a cap, but it is not unheard for them to go out.

 

Good luck with your Jr.

 

 

It just dawned on me that I have never modded a JR to add a permanent soldered in wire option that does away with the RCA jack usage, it may work better or not but I will have to try it on a junk unit one day.

Edited April 5, 2019 by imstarryeyed

[sethbramwell]

Thanks! I am currently using a component video cable for the RC connection. It's long as hell but gives the best picture I've gotten yet.

 

That being said, it did not occur to me to clean the rca connectors on the cable. I believe they are pretty clean but I'll try it.

 

I did clean the RCA jack on the jr, but I may give it another go with something to really get inside with de-oxit, perhaps a pipe cleaner.

 

Not familiar with a RF choke snap. Is that the black tubular piece I see on video cables a lot? I always wondered what the purpose was of that, LOL.

[ChildOfCv]

I have fixed over 100 Atari Jr's and most of the time:

 

1) RCA Cable is not thick enough for a great picture, the original one often gets old or lost and gets replaced by a thin un-shielded cable. Get a cable that is thick and has a thick inner cable and thick shielding.

2) RCA cable needs to be cleaned, clean that center pin and the prongs inside and out. Try a steel wool brush that is about as big as a toothbrush, look for those at a hardware store.

3) RCA Jack needs to be cleaned on the outside and inside, a real pain, use contact cleaner and a pick to scrape away dirt on the inside.

 

Ya know, this makes me wonder: Why do we connect an RCA cable to the console then run it to a RCA to coax adapter on the TV? I would expect an RCA to coax adapter on the console side, then running a real coax cable all the way to the TV would give better results. Well, maybe it's because the composite cable is more flexible.

[imstarryeyed]

Thanks! I am currently using a component video cable for the RC connection. It's long as hell but gives the best picture I've gotten yet.

 

That being said, it did not occur to me to clean the rca connectors on the cable. I believe they are pretty clean but I'll try it.

 

I did clean the RCA jack on the jr, but I may give it another go with something to really get inside with de-oxit, perhaps a pipe cleaner.

 

Not familiar with a RF choke snap. Is that the black tubular piece I see on video cables a lot? I always wondered what the purpose was of that, LOL.

 

Length of the RCA cable can matter so not too too long would be ideal.

 

A component cable is a good cable but be aware that they will often look great on more modern hardware but the output of the atari is not a strong a signal and may show differences.

 

I tried using a co ax cable from the cable company with an RCA to F adapter but it did not look good for me.

 

If you are using the RF Switchbox make sure you get an RCA to F adapter and use that instead, much much better.

 

RF Chokes are great and you can get them from Amazon for pretty cheap, however you might be able to salvage one from another device if they use a snap on style.. many devices do not use the snap on ones , but if they do definitely harvest it for your project. Those chokes can make a really big difference.

Edited April 5, 2019 by imstarryeyed

[sethbramwell]

 

Length of the RCA cable can matter so not too too long would be ideal.

 

A component cable is a good cable but be aware that they will often look great on more modern hardware but the output of the atari is not a strong a signal and may show differences.

 

I tried using a co ax cable from the cable company with an RCA to F adapter but it did not look good for me.

 

If you are using the RF Switchbox make sure you get an RCA to F adapter and use that instead, much much better.

 

RF Chokes are great and you can get them from Amazon for pretty cheap, however you might be able to salvage one from another device if they use a snap on style.. many devices do not use the snap on ones , but if they do definitely harvest it for your project. Those chokes can make a really big difference.

Thanks again. I picked up a Monster Video Cable from Goodwill today that is a lot shorter and seems to give a somewhat better signal.

 

I tried the coax cable too with no luck.

 

No switchbox, but unfortunately no coaxial input either. I'm stuck with just the screw terminals. I have an adapter somewhat Jerry rigged, but I'm waiting for a better one to come in the mail. Since I was a bit limited on my choice of wires to connect the adapter to the screw terminals, I'm wondering how much interference is from the TV itself.

 

I'll definitely try out an RF Choke. Thanks again for all the input!

[imstarryeyed]

Ah that 75 ohm converter is going to be a weak spot in that process, those old screw terminals just added another level of noise to the chain. The converters to go from screws to F most likely are going to be very low quality. In addition do try to clean those screws and terminal, but in the end, if possible, my opinion is find a good used Sony Wega Standard Def TV with composite, svideo and component. One of those TV's will give beautiful scan lines and not stretch the screen and play light gun games..

 

In any case good luck with your project..

[ChildOfCv]

 

No switchbox, but unfortunately no coaxial input either. I'm stuck with just the screw terminals.

 

Holy crap, does that mean it also has separate UHF and VHF antenna connections?

 

 

I tried the coax cable too with no luck.

 

Huh. That seems counterintuitive, but I guess you can't argue with empirical evidence.

[sethbramwell]

 

Holy crap, does that mean it also has separate UHF and VHF antenna connections?

 

 

Yes it does. I haven't seen one like this since I was a kid.

 

 

Ah that 75 ohm converter is going to be a weak spot in that process, those old screw terminals just added another level of noise to the chain. The converters to go from screws to F most likely are going to be very low quality. In addition do try to clean those screws and terminal, but in the end, if possible, my opinion is find a good used Sony Wega Standard Def TV with composite, svideo and component. One of those TV's will give beautiful scan lines and not stretch the screen and play light gun games..

 

In any case good luck with your project..

 

Thanks, I think I'm chalking this up to the screw terminals (I did hit them with contact cleaner and got some grime off but it did not seem to do much good) and the age of the TV. I cleaned the RF Jack as thoroughly as I could and now the picture comes in clear (slightly blurred on the edges but not bad at all) on my modern LCD TV. There's still a fair amount of snow on the old one.

[sethbramwell]

Just an update for anyone who is interested, I actually found a much more recent CRT that one of my neighbors was throwing away, complete with remote. I set it up and it works beautifully with the 2600. The recapping kit did come in the mail so I may do that at some point down the line just for the experience oh, nothing seems to be working very well!

[imstarryeyed]

Congrats on your project.. The TV choice can make a big difference, glad you got one that you really like. The most recent CRT's are the ones you are really shooting for.. I have a few Sony TV's and they are great for my classics.