Electrically connecting a flexible circuit to a support structure

A test system comprising:

• a device interface board (DIB) configured to hold devices to test, the DIB having a first signal pitch;
• one or more test instruments configured to send signals to, and to receive signals from, the devices on the DIB in order to test the devices, the one or more test instruments having a second signal pitch that is different from first signal pitch;
• and
• a circuit board between DIB and the one or more test instruments, the circuit board being configured to translate between the first signal pitch and the second signal pitch, the circuit board comprising:
• an assembly comprising a flexible circuit and a structure, the flexible circuit comprising an electrically conductive surface, the structure comprising an electrically conductive surface, the electrically conductive surface of the flexible circuit being electrically connected to the electrically conductive surface of the structure by a solder joint, the solder joint comprising melted solder bumps and flux.