Tuesday, October 11, 2011
Thanks Chris (my brother in law) for giving me his old NES system version 2. I had one years ago and missed it. I use to have a version 1 and sold it at a yard sale when I was a kid in the 90's and regretted it ever since. Now with all the info on the web I was able to do a couple of modifications, something I couldn't do or had no knowledge of all those years ago.
Mod 1 Lock out chip disable
This mod I did because of the 1 Hz flashing problem with some legit games here are some pics, the lock out was always a pain and caused lots of problems with start up.
Mod 2 Blue LED, give the old system a new look
The Led is tied to +5V on the anode and has a 220 ohm (R5) connected to a 74HCU04AP, I looked up the data sheet on the "04" and the output can sink or source up to 20mA not a problem with the blue led (10mA) with some calculation I figured about 8mA was flow through the LED, fine for me it's still very bright and give a modern look.