I have 2 Sanyo EZ 20 Monitors and now a 3rd one. Each one has the exact same problem; They only have a horizantal line going accross the monitor (these where all from either a Nintendo DK or DK Jr). I have a good working DK Jr board but no working monitor. On the monitor I just pulled, I tried using a new CGA to VGA video adapter only to find it does not work with the nintendo video signal (I even tried one of the inverter boards Nintendo made). 3 or 4 year ago I tried to get one of the two working but had no luck. Now that I have a 3rd one (This is a realy nice DK Jr I restored into a Double DK about 9 years ago) I realy need to figure this out!! The tube is very clean with no burn-in. I'm very good at doing cap kits, fixing wire issues, rewireing games for switching power supply, and things like that. So I know some basic electronics but I don't know how to trouble shoot a board down to the component level. I'm hoping someone can help me out with the process (what voltages levels to check and where etc..). I have the manual and schematics. Back when I tried to make one work, I replaced a few components like the horizontal and vertical drive transisters (after installing a cap kit of course).


I'd also like to know how to convert the Nindendo Video to work on a VGA monitor for testing purposes becuase I have a spare board. (I have one of the New CGA to VGA converter boards but I can't get it to work with this Nintendo board).

Any help would be greatly appreciated.

I did some testing and think the problem may be the IC401 chip that controls the virtical outputs and sync. It's a LA1464. I can't seem to find these, anyone know where I can get one?

Have you checked vertical output transistors(TR402,TR403)? Which version monitor do you have?
There were RC and RB and RC version 2. But usally vertical outputs when a straight line left to right on tube. Also dont forget to recap.