Jump to content

My first ADAM - no video

Recommended Posts

2 hours ago, martin1b said:

I as able to get it hood up to a monitor, using composite out (FWIW). See below:

Also, I wonder about the lack of color.  It may be necessary to take a closer look at the LM1889 in the RF box, as well as the 4066 (U23) on the board near (or possibly under) the box.


If you remove the cap on the RF box, you should see an 8-pin connector.  Pin 8 is the clock input and should be a 3.58MHz sine wave.  Pin 5 should be a bias voltage around 5.8V.  Pin 4 should be +12V.  Pin 3 is the red component and should be an AC signal dancing around pin 5's voltage.  Pin 2 is audio input, and we know from the RF output that that works.  Pin 6 is the B/W part of the signal and should also be dancing around pin 5's voltage.  7 is the blue component and should also be dancing around pin 5's voltage.


If it's like the Colecovision, the board will be mounted upside down with the traces on top.  The LM1889 is the dual row of pins in roughly the middle.  Pin 1 of that chip should have a phase-shifted version of the clock signal and pin 18 should be phase-shifted in the opposite direction.  One leads, the other lags.


So check if you see any color output on the red and blue especially.  If you do, then you should also see color output on the monitor.

Edited by ChildOfCv

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...