Wynn,
I don't have the V4, but it sounds like the setting procedures are similar to the V3 that I do have.
According to my V3 instructions, you need to hold down the PB for a few seconds even after you plug in the power. You probably are doing that, but I thought I'd mention it anyway!
Since apparently it is working with the default setup, it sounds like the issue may be the PB switch.
You might take a magnifying glass and look at the solder connections, just to make sure they are all good (had a problem once with a JMP-2 where the soldering was missing on a few pins).
After that about the only thing you can really do is to contact Ztron.