I keep getting 56 faults on a gearless TIV with a Magnatek drive. What are the common things that fire 56's?

Not getting de input, are you getting drive faults on drive? Also check power supply voltages, make sure they are on high side of suggested voltages. If that don't help we can go from there.

F904 which is low line fault I believe. I think it's power related but can't prove it yet. Sometimes it traps people and/or I get there and it's OOS. I went over 1M, S, MCF, MFC relay contacts and connections. S and MCF had high resistance so I put in new relays. I pulled all the PCB's and re-seated them but had to leave for an entrapment. I'll check the PS voltages tomorrow. Thanks.

I checked all the power supply voltages today, all were ok except the 5V was a little low at 4.970. I cranked it up to 5.012. Measuring at the DSP PCB test points, not the backplane. The car ran on CYC for +4 hours with no faults, but it's been known to crap out after 2 days of no problems.

Crank up to 5.12, what slot is PMI 2 in? I think you have something else going on 56 and 904 on the drive are common faults not fatal. I maybe wrong without my notes but what does the smart fast say the state of the car is in when you have a entrapment. ###init?

Also run the confindence test after you crank up the power supply, make sure everything is a go.

Something that is not done enough is checking for AC component on your power supply. Measure the DC then switch the meter to AC. Anything above 25mv is suspect on a regulated power supply. Once the capacitors dry out, it will introduce AC into your logic. Even cycle your CPU at 60 Hz.

Why do I always forget to check for AC component??? I guess because I'm used to working on old relay stuff..... Thanks , I'll crank up the 5V a little check for AC when I go back. Are the caps you're talking about are in the PS itself?

I always check voltage at back plane.... Habit, also there was a bulletin about those older power supplies that get funky over time...
Thanks J.

Also one more thing, does it have the old orange reverse phase relay on it...
If it does that might be suspect, as well. Carlo gavazzi, I think are the ones recommended to swap those out with... Thanks J.

Not sure I know how to do the confidence test. I did the FLTP check on the PMIs and had no faults.

Where at on the backplane?
I've never seen a VM not jumped.... yes they're orange. Which ones are the good ones to replace them with?