have you looked through the EV1 troubleshooting section in the EV1 manual?
go to fsip and check that out
it mentions in its troubleshooting section about symptoms such as what you are having and has some key points to check on the panel. i'm sure it would be of some great help for you to read this.
ht tp://ww w.fsip.biz/Documents/EV1.pdf
(remove the spaces i put in the url to make it work)

good luck :o)