The PowerCab is the best programming environment you can have. The
QSI V6 decoders are some of the most notorious "problem children". To
read the CVs in a V6 decoder I -often- have to go back to the individual
sheet and do a "Read Full Sheet" ... often several times before I get them
all. You can also go to the "CVs" pane and read just one CV until you
get it read.
Having an entry in your DecoderPro roster that has a few RED CVs is
not a problem unless/until you feel the need to change them and want to
first read them.
You may have better success if you can set up a totally isolated
programming track section of your layout. Be certain to read up on
how to do that the "best way" before you do so - there are instructions
on several web sites for doing so - just Google "NCE PowerCab
programming track". Locomotives "creep" during long read all CVs
and it is -very- important that they not go past the end of the
programming track. The reason for having an isolated programming
track is to reduce any other loads that might reduce the ability of the
PowerCab to read/write CVs. Many guys use a siding somewhere
that can be isolated with the flip of a DPDT.
I have about a dozen V6 equipped locos and have stopped using them.
They are waiting to be converted to Tsunami 2 decoders. (There are
other problems with the V6 decoders than the difficulty reading them.)
DP is absolutely the best and I don't even consider any other method
for programming locos.