Home Forums General Discussion Technical Questions Miprom 1, No UA output

The car is on the buffers trying to level up. Everything is coming on, LR and SVC outputs come on, but no UA output. LRU input is hot, US1 and US2 are made.125volts to the output board, can ground the UA output then the pump starts and the up slow valve is picked and the UA relay comes on. Only has 50psi at the valve but that's another issue. Safety string and the doors are made as well.

The first thing I would do is replace the Output Board. If you do not have one you may try switching one output bd. for another to see if the problem changes. The are 2 IC's on the backplane that could also be causing this type of problem. Or the backplane itself. You need to have some spare parts to change out when troubleshooting these type of problems.

Spare parts.....my boss has an issue buying a fuse. I grabbed a kone laptop from another place and ran the output test on the board. It shows good and actually kicks on the pump when it gets to the UA output. The output board has been changed as well as the power supply board.

I just had this issue last month. Replaced the main relay board.

So a quick thing to eliminate and isolate the lack of the output board not turning on is to replace the I/O interface board. And as mentioned before there is an IC Chip on the Miprom cardrack backplane that can cause this kind of problem.

Well he has me doing something else for a few days. I guess that is the way the industry has gone, just make an appearance and then make another one somewhere else.

I just got around to explaining what happened. Apparently the motor and pump were pulled, I found out later. I was under the impression that just the valve was changed. When it all went back together then it wouldn't run. P1 and P2 from the motor were not put back in the correct spots. Relocated them to the correct spots and all was well. Adjusted the valve and it's back in service. My advice is.......put the phones down.