IB-1103 Frequency counter

[TChesek@Epix.Net]

I bought this counter about 1 year ago and have used it intermittently. Recently while doing my "investigative" work on nixie driver chips I noticed a lot of heat coming from the power supply pcb. I found 2 heat sources on that board. First are the full wave bridge diodes for the 5 volt circuit and second is the current limiter transistor in the 16 volt circuit. These devices become very hot to the touch. I might expect the 16 volt current limiter to get warm, not hot, and the diodes for 5 volts should stay cool. This should be a no brainer but it has me puzzled. I have gone as far as COMPLETELY rebuilding the power supply board with all new components both solid state and capacitive. When the counter is in use the externally mounted 5 volt regulators (2) barely get slightly warm to the touch as you might expect. If I remove all output connections from the power supply board the 5 volt bridge diodes stay cool but the 16 volt regulator still gets very hot. I can't imagine this circuit being normal with these heat issues. 

I have no opinion at this point on the 16 volt limiter heat issue. I ponder the possibility of the 5 volt bridge diodes being under-rated, but these diodes are rated at 3 amps and each regulator is rated at 1 amp. Does anyone have any specific experience with this counter/issue?

73 & tnx,
Tom K3TVC

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