After having our Nitris DX in operation for almost 10 years, I thought it would be high time to open it up again and not only give it a good dusting but also to replace the rather old and noisy 80 mm Delta main system fans. I decided to pick up a pair of Austrian designed Noctua fans which are very nicely made and extremely quiet. However, these fans don't have the same specs as the original Delta's (RPM speed is lower in the replacement fans). More on this to follow.
In addition, there is a 40 mm PSU cooling fan which sounds like a turbine when powered up and given the hard mounting to the metal PSU chassis which in turn makes contact with the main fan metal support "leaf", the sound the NDX was emitting had some nice harmonics producing beats in the 90 dB range..., borderline unusable I/O box unless rectified. Actually, one could argue a health hazard. In short, I replaced this fan too and while the overall cooling might not be quite as effective as it was before, the unit is virtually dead quiet and I actually can hear my timelines now! I couldn't wipe the grin off my face after connecting everything and powering up.
I won't go further into the hardware and noise issues but I wanted to lay down the foundation for my questions. Why? Because Symphony is now complainig intermittently about a "fan malfunction" and stops timeline or clip playback. Clearly, there is no fan malfunction because all three are working perfectly well. But..., evidently NDX communicates in some fashion (over the PCIe bus) with SYM telling it that there is a problem. Of the three fans, only the main two PCB 80 mm fans are three pin and are therefore in principle speed controlled by the NDX hardware. The PSU fan is a two pin fan powered internally by the PSU so it is not controlled by the PCB nor has direct communication with it other than possibly through the 20 pin molex power connector to the NDX hardware. So, with that out of the way, I was hoping someone with NDX hardware knowledge could help answer the following:
1) How does the NDX box communicate with SYM at the fan "malfunction" level?
2) Does the communication only happen between system controlled 3-pin fans (i.e., the main fans) or is the system also monitoring the PSU fan through the 20 pin connector?
3) What does the NDX hardware expect in terms of fan performance/specs? Is it RPM based only or is there more to it?
4) If I know the now quiet NDX box is operating properly without excessive heat (I haven't noticed the passive chip heatsinks or the PSU overheating after having the system on for a day), is there a way to disable this notification in software (e.g., through the console) which prevents proper functionality of the software?
Any insight or advice is much appreciated.