Miprom 21 CPU Replacement

I recently worked on a shutdown that required me to replace a CPU board on a Miprom 21. I swapped the BATRAM chips and the piggy back board with chips to the new CPU board. Now when I connect to the CPU with the World Tool, I get an error message stating that drive and CPU parameters do not match and that I have a bad floor table. I have not had this issue before, looking for some advice on how to proceed. Thank you.

This is what happens if you don’t use the old U38. You just need to go to drive and do a ReInit, then build your floor table. I can’t say why you have to, but the BatRams don’t last forever. Probably a good time to replace it. What was the original problem with the CPU?

Oh, and if the ReInit doesn’t work, and it will tell you if it doesn’t, you will have to do an Init. But this will put your drive back to defaults. Usually not a problem, especially if it was a new install. But I have had trouble on certain MOD jobs that would not run with default parameters. Had to go through the setup manual page for page to get a running car. Ideally the drive parameters are recorded on site.

I believe that U37 and U38 are the BATRAM chips, they were for sure swapped to the new CPU. The CPU was replaced because I could not communicate with the controller, no heartbeat LEDs on MSU, PIO and CPU. I tried swapping the MSU and PIO first, still no heartbeat or communication. After swapping the CPU (twice, found a bad board on the job labled good), I am able to communicate with the controller. I will try a ReInit on Monday.

U38 is the battery backed RAM chip, U37 is a Real Time Clock

A bad CPU can whipe the U38 too so the chip may be fine.

Car is back in service.

I tried a REINIT, did not work. INIT did work. I built a new floor table and the car was off and running. Any time I hit a terminal landing I would drop my NTS relay and log fault 38. This is a mod job, but the machines were changed after the initial modernization. I looked at my Motion Averages, the car was running 50 fpm slower than contract speed. ME Base Speed (motor rpm) needed to be changed to jive with the new machine.

Thanks Indirtwetrust