Closer look: Inside the Case
To get into the TNN500A, you open the front and rear panels, unscrew two rows of big screws that fasten the side panel to the top and bottom slabs and unfold the case as you do a book: unfastened, the side panel can rotate on its hinges:
The left panel carries a PSU and aluminum ledges for installing hard disks and optical drives:
The heat generated by an installed hard disk drive, for example, will be transferred to the ribbed side panel via this ledge.
The flat PSU is just spread along the inside of the side panel. Its design is most unusual as all its elements have a low profile. The big and flat high-voltage electrolytic capacitors catch the eye in the first place:
A large plate, smeared with thermal paste, is fastened to two bars that take heat off the switch transistors and diodes:
This side-view snapshot shows you that the power transformer also contacts the plate:
The plate, in its turn, gives heat out to the side panel of the case. For better heat exchange, they use thermal paste:
Other PSU components, which don’t generate too much heat, are cooled with air that comes through the vent holes in the PSU’s cover. The characteristics of the unit can be read from its casing:
This PSU is a most curious device. It is called ZM-350, but its total wattage on all the power rails is 300W. However, the maximum currents on the power rails don’t comply with the specification of 250W units even! The maximum current on the +12v rail is recommended to be 13amp for 250W PSUs, while the ZM-350 can only supply up to 12amp. What’s most strange, “ordinary” PSUs from Zalman are much more honest: for example, the 300W ZM300B model provides up to 18amp on the +12v rail instead of the recommended 15 amperes.