Exp. Mod. #1 - Video Issues

[Ikrananka]

I have just installed an F18A and it works great via VGA with an old Dell computer monitor that I have. However, I also want to be able to use the Exp. Mod. #1 with the unit and know that the only current option is a composite video mod off of the RF board. The Dell monitor includes a composite video input. I have the composite mod that was done by doubledown years ago (LM318 based) and have hooked this up. However, the image I get on the Dell monitor is barely recognisable and continuously scrolls from bottom to top. I have attached a screenshot below.

I have another CV with 5-11under's component video mod which includes composite out to support the expansion module. Unfortunately, I get exactly the same image issues experienced with the doubledown mod when using the Exp. Mod. #1.

I tested the Dell monitor with a Wii unit via composite and it displays fine (as good as composite gets I suppose) and so I don't think it is the monitor - although it may be fussier than some.

I also tested the composite on my TV and while it is much better than the Dell monitor the image is absolutely shitty (second picture attached). VERY blurry around the edges with a lot of haloing as well.

Any suggestions as to what the problem may be and possible solutions would be most welcome.

Any better alternatives to the classic LM318 mod for use with the Exp. Mod #1?

[cdn2a]

Hey dude.

 

Have you tried testing the CV by it's self on RF?

I know over time in the RF circuit the inductors can drift and need to be re-tuned by a little bit. Perhaps the output frequency is off?

[Ikrananka]

Have you tried testing the CV by it's self on RF?

I know over time in the RF circuit the inductors can drift and need to be re-tuned by a little bit. Perhaps the output frequency is off?

 

So I tested one of my units on RF and it looks just slightly worse than the TV composite image in my first post. So, how does one re-tune the RF section?

 

Would it not be better to use an Atari 2600 composite mod (e.g. http://www.coolretroprojects.com/Atari-2600-7800-A-V-Mod-Kit-NTSC-PAL.html) connected to the video line output from the expansion module thereby completely bypassing the CV's RF circuits?

[cdn2a]

So for anyone who reads this later and wants to try tuning the RF portion of the coleco, check this thread.

 

http://atariage.com/forums/topic/247913-refurbishing-a-colecovision-question/

 

In the picture, the top one tunes the sound. The bottom one tunes the picture. Make sure to change between channel 3 and 4, to get it adjusted properly.

[cdn2a]

Ok, So if you want an easy composite mod for your Expansion Module #1, do this.

 

Using the Coleco LM318 board and circuit, and this picture, hook up these wires,

 

Orange - Video in

Red - +12V

Black - Ground

 

Audio can be grabbed from the top of R26.

(Expansion adapter connector side, (Pic is upside down))

 

I tested it out and it looks good!

 

Edited May 3, 2016 by cdn2a