Author Topic: VFE Bumblebee troubleshooting  (Read 188 times)

zgrav

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VFE Bumblebee troubleshooting
« on: November 21, 2019, 09:30:42 AM »
Finished assembling this pedal and now troubleshooting an odd problem.  It is a split-rail design, and when powered I am only seeing -1.2 volts on the negative supply.  If I disconnect the negative power going to the main board, the output from the charge pump is OK on both the positive and negative outputs.  What I then see is that I am getting about 3.5 volts on the negative power traces on the main board with all of the transistors and the two ICs removed from their sockets.  Also getting the same 3.5 v on the negative circuit path when the transistors and ICs are in place.  I am looking for unwanted solder bridges but have not yet found any.  Since that is about 5.4 volts less than the positive voltage going in to the main board, does the voltage reading itself suggest any particular places or parts to check on the board?

zgrav

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Re: VFE Bumblebee troubleshooting
« Reply #1 on: December 02, 2019, 10:17:08 AM »
Updating my post about this issue in case it comes up for others later in a search.  The problem I described in the first post was due to getting the power connections wrong between the switching board and the main Bumblebee board.  The read the markings on the main board for "V-, B, and V+" to mean "V-, G, and V+"    That is not correct.  The connection diagram shows that the 3 wires from the switching board that are "G, V-, and V+" should connect straight across to the three holes where the v-, b, and v= markings are.  When I followed the diagram instead of trying to use the markings the power supplied to the main board was correct.