I am not sure what you are looking for.
In terms of the hardware, if you are looking for schemtics and such, you will not get them as that is proprietary information that Quintum will not release. If they did so, then anyone would be able to make their own (of course they would still need the software, but you get the point).
For troubleshooting, you should make sure that you have a good background in telecommunications. This is much more important than the IP side as telecom is harder to fully understand than IP. There is more signaling for telecom than IP. Once you understand telecomm, you will understand much of how to troubleshoot any VoIP gateway, not just Quintum.
Specific to Quintum will be your ability to understand the event log such as the ch log, CAS, H323 and such. Most of these logs are industry standard, for example, most of the H.323 signaling (at the higher level) is based on ISDN/Q.931 signaling (again telecom). If you were to to understand ISDN signaling, you would be able to read the H.323 log. Additionally, there should be resources on the web to understand the other messages of H.323.