1) NCE has 3 product names used in its manufacturing history. a) MASTER SERIES b) PowerHouse c) PowerPro
2) Some if not all PB205a have no model name/number markings on the front.
3) The DB3 and SB3 were NOT thermally rated for continuous 3A duty and required an external short circuit protection in the form of light bulbs to be added. See manual. HOWEVER, the DB3a and SB3a replaced these non "a" versions addressing the thermal issues and adding more current at no additional cost. Unfortunately not caught in time, the first release of the DB3a/SB3a manual did NOT remove the reference for the need for light bulb protection. The new DB3a and SB3a designs are based on the PB105a. See note 8 below.
4) The original PB105 can be special ordered from NCE for those who wish to use this version to match the ones they already have. However, the PB5 is the intended replacement.
5) This specific number is missing from the manual. Value is extrapolated based on the design.
6) These specification is the maximum power supply voltages recommended for use as stated in the manual. The ABSOLUTE MAXIMUM voltage rating in the manual are slightly higher but those are the voltage ratings in which if exceeded for any reason or moment in time runs the risk of destroying the booster instantly. Stick with the recommended ratings.
7) The presence of absence of the "Normal/Loop" switch on the front panel is the defining indication of the booster capable of supporting reverse loops directly.
8) The DB3a and SB3a are rated at 5.1A*. Unlike the PB105a booster, the SB3a and DB3a cannot sustain a continuous 5A load longer than a few seconds. HOWEVER, there is NO damage to the booster and no external protection is required. The booster will simply shutdown acting as if a short circuit occurred and self clear after a small delay. In practice on the layout one should never see this happen unless one test the booster on a Test Bench. *= With fan cooling and nothing is said about how this is to be done properly. In bench testing I find no need for it when the booster is place in open air.