Hello all,

I'm using a Yaesu VX-3R for a school project. To power the radio for testing purposes, a power supply simulating batteries and a custom pcb to condition the output power is used. The way the radio was connected to the custom pcb was by clipping onto the the prongs where the battery metal contact (+ -) pads push against the stock battery. The photo below show this.

After some time ( maybe like a month or lees) it stopped Tx/Rx when connected using the mic/sp port. However it does Tx/Rx when using the ppt button. One thing that did happen a few times was a short circuit across the metal frame of the radio because of sloppy connections. Not sure if that is to blame. We have used another radio to confirm that the rest of the setup is working.

Any ideas why the mic/sp port would stop working?

 

The mic/sp port is for an input of a microphone and speaker. Depending on what was shorted and where, some SMT component(s) may have failed. Did you see or smell any magic smoke when you noticed the short?

 

I didn't smell or see any smoke . which has made this more difficult to determine what the problem is. It's brand new, out of the box.

 

Check to see if your unit is under warranty, then have Yaesu fix it. They guard their schematics pretty well, so it is unlikely you will get a schematic for your radio. If you try to repair it yourself and mess something up, you will void the warranty.

 

I'm going to send it out hopefully they can fix it.

Does anyone know what the following is circled in red?

It is only on vx3 (right side) model and not on the vx2 model (left side) as shown below.

It is copper wire coiled over a permanent magnet. Inductor possibly but not sure what its doing.
The ends of the wire are circled below.