Since system 9 MPU boards are getting more and more rare I am contemplating performing the MOSFET upgrade to the lamp matrix on the MPU in my Space Shuttle. My board was purchased NoS about 5 years ago and it has the cement resistors, recently I had an issue with some controlled lights and while troubleshooting I noticed that two of the resistors were getting extremely hot and one had almost backed its way out of the solder point creating a poor electrical connection. I have tested, cleaned and re-soldered the resistors back in place but there has been some heat transfer and discoloration on the board. For obvious reasons I want to remedy this issue so the board lasts for many more years. I am no stranger to board work but I am hesitant until I get some feedback from some others who have successfully performed this upgrade as I have seen two methods one using jumpers in place of the resistors and another method lowering the working voltage using 1k ohm resistors. If you have performed this upgrade on a system 9 MPU in particular please give your feedback, pictures, materials list or links to existing documentation for this procedure if possible. TIA!