Why ColecoVisions sometimes have good rf, and other times have bad rf

[Hannacek]

Does anyone know why some ColecoVisions have really good quality rf, while others have bad or really bad rf? I am talking about rf quality on CRT TVs, flat screen and modern TVs is a different discussion. Static, noise, distortion, the classic signs of bad rf, some consoles have them, and others produce crisp clear picture on rf. I have had Atari 2600s, some with insane good rf quality, and some with really bad rf quality.

 

Does anyone know why these retro consoles sometimes have really good rf, and sometimes it is really bad? I just got a Coleco Gemini which has really good rf, and an Adam computer which has bad rf. It is the same tv, same rf cable. Is there anything I can do to improve the quality of my Adam's rf signal?

[Osgeld]

Tolerances in components + age + storage conditions over its life

[Hannacek]

Can you do anything to improve rf quality, or do you have to buy a new console and see if it has better rf quality?

[Hannacek]

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Edited June 9, 2018 by Hannacek

[mobiusstriptech]

There is also the issue of basically no filtering on the boards and between board revisions different routing. The routing in general on these kind of sucked anyways. The boards are practically designed to generate noise and interference.

[NIAD]

If you have a system with bad RF output, the answer is to buy an RF Filter that connects between the console and the TV. This will/should clean things up.

 

The other option of buying another system is a crap shot unless you can personally test it and even then, there is no guarantee that the RF output won't degrade over time and use.

 

FYI... I had a Prototype CV that had amazing RF output even 35 years after it was built. A stock CV with very good RF output and another stock CV with piss poor RF output that I had modded to Composite Video.

[Hannacek]

FYI... I had a Prototype CV that had amazing RF output even 35 years after it was built. A stock CV with very good RF output and another stock CV with piss poor RF output that I had modded to Composite Video.

 

I have heavy Atari 2600 6 Switch. It was made in the first year of 2600 production. It has probably the best rf quality of any console or computer I have ever owned.

 

They cut corners to save money after the first year of Atari production. Coleco has to have done the same thing where once they get the prototype working, they strip out parts and do whatever they can to save money.

[ColecoJoe]

Don't forget to try a new cable. A lot of times those cables go bad.

[HeadcolorsTV]

I would also point out, from recent experience, that the cable you use is very important. I'll link a recent post from a thread I'm updating further down, where I learn that (a.) higher resistance is desired—I think 75 ohms is the standard—and (b.) the cable must, must, MUST be shielded. Audio RCA cables (male to male) that you get at Radio Shack just won't cut it.

 

Basically, when it comes right down to it? The cables used in 2nd generation RF were lower-grade coax (in fact, I remember reading someone in AA having good success with using RG6 coax and the correct adapters as a replacement RF-out. For my experiment, I took the "from console" portion of an old Sega Auto RF Switch, unsoldered it from it's PCB (so it becomes a direct connection, soldered it to a spare composite video cable RCA plug (I made sure it used a shielded cable), and hooked it up to my CRT using an RCA female to coax male adapter. It worked beautifully.

 

http://atariage.com/forums/topic/252121-post-ben-heck-mod-issues/?p=4046940

[rodge2001]

I generally just put up with it but I do wish I could improve it but I'd rather not mod my console in any way. I wonder if RF interference is from internal nature of ColecoVision itself or instead from external sources picked up by either the console or the RF cable. I'm often moving the RF cable into different positions to get a decent signal. I never realized signal degradation could be from the CV itself.

 

I'm not sure if a shorter cable or longer cable is most beneficial. Or maybe a thicker more shielded cable might make a difference. It may help to keep console away from Power Supply and/or power source. And also free from contact with any other wires; even my controller wire. I know my signal gets worse if more than a single cable is used and my signal really gets bad if I split signal to two TV's.

 

I've seen various RF interference filters but they seem a bit pricey and may not even solve anything. I've also seen things called ferrite core snaps that attach to a cable but those may not work unless many are used although the cable can be looped several times through a single large ferrite core but I have yet to do so.