Refurbishing a ColecoVision Question

[bsalapek]

Yesterday I acquired two ColecoVisions in a box of random old video game stuff. They have original power bricks but an NES RF Converter cable. I tinkered with them for a bit and was under the impression that they did not work until I bumped the RF connection. With a little fiddling of the RF cable connected to the back of the console (rotate, pull out, reattach...), I am able to get picture and sound on the TV. The picture is a static-y mess that flickers color to black and white a few times before going to black and white full time. The sound, on the other hand, is fine.

 

Reading a bit on here has pulled me in a few different directions. It doesnt seem like the on/off switch/video issue since it is not scrolling. I found another thread, which seemed more along my issues (https://atariage.com/forums/topic/200963-video-output-issues-with-my-colecovision/) where it was attributed to the NES RF converter cable.

 

It almost seems like a combination of an improper RF converter and bad contact on the RF output of the system. My first inclination here is to install a composite video mod (which is the direction I would like to go with these consoles anyways).

 

Does it seem like I have approached this in a logical fashion? Is there anything I have 100% skimmed over that should be addressed before trying to mod it?

 

Thank you for your time!

[bsalapek]

Just an update:

 

I realize that this kinda was a rant lol Sorry about that.

 

I got a new RF cable with a RF->Coax converter on the end and the 1 Colecovision to work PERFECTLY! I was very happy about that. The other one has a much clearer picture but is still in Black and White. I fiddled with the channel select switch and it didn't help. I plugged in an atari expansion module and that is in Black and White, too.

 

I have ordered the AV Mod and will see if that helps at all. Hopefully it does!

[Hannacek]

An NES switch box has an automatic switch mechanism, so it won't work with older systems like a ColecoVision. Either use an Atari or generic switch box from the 70's or early 80's, or use the coax adapter.

 

All old consoles have a potentiometer and/or coil inside the rf modulator that can be adjusted to fine tune the picture. This is done at the factory, so you have to open up the console to readjust it. It can become out of alignment, or it won't work with a modern TV unless it is readjusted.

 

If you open up the ColecoVision there is a metal box in the back where the rf cable plugs into. Take off the metal cap. There should be 1 or 2 spots where you can adjust the potentiometer or coil to fine tune the picture. If you have an old CRT it would be easier to get it working on that first before you try to get it working on a modern tv. Just get a small screwdriver, you might also need a small Allen wrench, and adjust the 1 or 2 potentiometers until the picture becomes normal. I attached a picture of the rf box, which shows 3 holes you need to make the adjustment. It looks like only 2 of the 3 are the spots that need to be adjusted. One of the holes might not do anything.

 

If everything is working except there is Black and White and no color, this should solve the problem.

[bsalapek]

Hannacek - I had opened up the RF Mod while checking out the system, but had no idea about an adjustment on it! I am excited to try it out and see if it works!

 

Is it ill-advised to adjust the RF while the Coleco is powered on and hooked up? I can't imagine how to get a good picture otherwise without a lot of trial and error

[Hannacek]

You need to adjust it when it is hooked up, so you can see what you are doing. I don't remember exactly how the pots on the ColecoVision work, but I think one is for sound, and the other is for video. There may be a 3rd one for tint or something else. You can leave the sound one alone if the sound is fine. Just test each point to find out which one does which.

Just turn on a game like Pit Fall, Frogger, or Donkey Kong where you know what the colors are supposed to be like. Just get a very small screwdriver and slowly adjust the pots and see what happens. The picture will be better when you remove the screwdriver and put the rf shields back on, but you can get close enough with them off. When you think you have it right, just play a few different games to make sure the colors and sound are adjusted properly.

All old consoles have these adjustments, and they fine tuned them at the factory. Back in the 70's and 80's TV's had a bunch of adjustment knobs, so people could fine tune the settings on their TV, and they didn't have to open up the console. Modern TV's don't have the same adjustment knobs as old TV's, so sometimes you need to open up the console to fine tune them. Also, these consoles have been out in the world for decades, so its understandable that the settings from the factory may no longer be good.

 

This should solve the problem.

[bsalapek]

So I have a new issue and wonder if someone can help me. Upon opening the Coleco and inserting a cart, I inadvertently damaged capacitor C70 (which reads 101 J) right beside the cart slot. My motherboard is revision H2-1.

 

Checking out the forum, Rex had pointed out that the 101 J capacitors are "100 pf 5% ceramic capacitor" but later mentions that different revisions of motherboards used different capacitors. Are there diagrams somewhere for these motherboards I can reference?

[bsalapek]

Just for closure on this thread, I was able to repair the Coleco and fix the video issue. Thank you Hannacek for pointing out the adjustment screws on the RF.

 

The capacitor I bought to replace C70 was this:

http://www.ebay.com/itm/271827169817?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT