SSH works, but no video

[SvdSinner]

Is there something I can do to debug why the HDMI monitor gets no signal from my Pine64?  Initially, I tried an old 4:3 monitor and found info that 4:3 monitors aren't supported.  However, even using my newest 1080p monitor, I get nothing.  Are there settings or error logs I can check via SSH that could give me a clue what is going on?  Ideally, is there a way to use the older 4:3 monitor?  

Technical details: 

• Debian Mate (3.10.102 BSP 2)
  
• Pine64- 2GB  from Kickstarter
  
• I am using a HDMI - DVI adapter on the monitor-side of the cable.  I've actually tried 2 different ones, neither make video work.   None of my monitors have HDMI inputs.  I can test it on my TV, if anyone thinks it is worth trying.
  
• I'm not a Linux guru, but have used it occasionally for the last 20 years.  I won't take any offense if you talk to me like a Linux newb.
  

Luckily for me, I'm setting up my Pine64 as an OctoPrint server, and thanks to this great thread, I was easily able to use SSH to get things set up to work as I needed.  However, I'd still love to get the video working if I can.