HP9114A Battery Charging Circuit Board

[aj04062]

I have two of these packs that do not work with new batteries. Something is amiss on the PCAs. These PCAs have 5 total components: Transistor, Rectifier, Diode and two resistors.

The connector that plugs into the drive reads 6V, but the drive will not turn on. If I bypass the board and hook directly to the battery, the drive works so this issue has to be in the board somewhere. It seems to not be getting the current it needs to run the drive.

I have replaces the 6.8V diode and the transistor (TIP41A). The rectifier doesn't come into play here. What is baffling to me is it seems like all the current must run through a 4.7k resistor. This doesn't make sense to me.

Has anyone else had issues with these 5 part charging boards and diagnosed the issue? I have a much more complicated (earlier version I think) board and it works FINE.

I have sketched out the circuit if it would help.