Hi, I've got an updated model to my 12V Automotive Timer Simulation here: [https://easyeda.com/Dkraemer/timer-rev-b](https://easyeda.com/Dkraemer/timer-rev-b)<br> <br> I'm having a lot of trouble with the transient simulation settings. Whether or not the simulation runs seems to change day to day. I don't think I'm making any changes that would affect the circuit so much that I'd get a 'time step too small' or "circuit too complex" error. Is there a more definitive guide to transient spice setups? I've not been able to find a pattern and the help file isn't useful or clear. It says: (Stop-Start)/time step<10,000, but I don't know how to use that, especially when ".tran 0 15000 10m" runs, but not ".tran 15000". If I enter the first parameters into the simulation setting box (start time is 0, stop time is 15000, max time step is 10m) I get the "time step too small" error. I've been banging my head against my desk and have searched the forums, the help files and google for this but I can't figure it out.