Hi Gustavo
1 We have a dedicated technote on bad checksum errors here:
http://www.eventide.com/AudioDivision/Support/Knowledgebase.aspx
If you can't fix it as suggested, it may be necessary to change an internal battery. We still have it. It requires a skilled technician to be installed though. It's available in our web store.
2 You can check the presets list (and other documents) here:
3 The only way you can add storage capacity is by purchsing PCMCIA cards. As the 4000 series has been discontinued long time ago, we no longer have these cards. You need to search on the internet for them.
all te best
I
