It’s nice to have a convenient set of tools available for troubleshooting that aren’t part of a permanent test fixture or automated system. Every situation is unique but there are scenarios where a quick, independent verification of voltages or power levels is all that’s required and will often same time and money. Troubleshooting rework or modifications to a circuit board are frequent activities where the focus is on macro level functionality. Prototyping in the early stages of development is another activity where attention is on gross performance characteristics, knowing the painstaking detailed measurements will come later as the design matures.
- Is there RF signal present, and is there gain across the amplifier?
- Is the voltage there and is it about where it should be?
- Does the unit switch states or respond as expected?
Pictured here is a hacker project of a wireless keyboard. A couple of modifications were made to the keyboard and Oscium’s iOS Test suite of tools were used to verify the modifications were done correctly.
The first modification to the keyboard was the addition of an RF “pigtail” at the transition between the processor/transceiver SOC and the antenna. In the picture above you can see a piece of semi-rigid coax cable soldered on to the circuit board. This was done to eliminate interfering signals in the frequency band of interest from corrupting the measurements out of the transceiver. Oscium’s WiPry-Combo power meter and spectrum analyzer was used to verify the connection to the board was good and would be suitable for use in the “big” mega-buck test station.
The second mod was unplanned but proved necessary. A battery pack was rigged up to power the keyboard when it was dismantled for testing. When the back cover is removed the battery compartment basically goes away and there’s nothing left to hold their batteries or the electrical contacts with the keyboard. Now this may seem a bit trivial at first, but problems like this pop up more often that you’d think. The trick to solving them is to take a creative approach to the solution, make use of the materials on hand, and use a lot of ESD safe kapton tape.
In the picture below you see two double A batteries held together end-to-end with wooden Q-tips and a lot of kapton tape. It was probably late at night when this brainstorm occurred and there was no one else in the lab to see the kludge take place. After everything was put together, the voltage across the batteries wasn’t right; it measured about 2 volts instead of the expected 3 volts. Oscium’s iMSO-104 oscilloscope was used to monitor the voltage across the battery pack as wires were wiggled, the batteries realigned, and as even more tape was applied to hold things in place.
(Re-posted with permission from our valued partner Oscium iOS Test Tools)