Behringer Cable Tester CT100 is a pretty nice and cheap cable tester for all kinds of audio cables.The CT100 accepts many type of cable you might use in a recording or live performance situation: XLR, mono and TRS phone (¼”, 1⁄8″, TT), RCA and even MIDI. here are three operating modes: Cable Test, installed Cable Tester or Tone. The CT100 can check for continuity, intermittency, the presence of phantom power and grounded shields.
Behringer Cable Tester CT100 Features:
Easy-to-use cable tester for common audio cables.
Tests XLR, 1/4″ TRS, 1/8″ TRS, TT TRS, RCA, and MIDI cables.
Microprocessor-controlled modes include Cable Test, Installed Cable Test, and Tone.
Runs on 2 AA batteries.
Many connectors are on front panel, but some of the connectors are places on the sides of the device:
Because some Googling did not show up any teardown or other report that shows what is inside CT100, I decided to take a look.
Opening means removing eight screws and two nuts.
When those were removed, the metal front panel can be pulled out and we can see what is inside.
There is not very much interesting seeing on this, but some details. The device has one big main chip, what is most probably some micro-controller chip where software does the most test tricks. In addition to this the circuit board shows two 74HC138 1-of-8 inverting decoder/demultiplexer chips. those seem to be mostly go to controlling the front panel LEDs. There is a 4 MHz oscillator crystal or other resonator for generating micro-controller clock. Different input and output connectors seem to be wired in parallel. There are many diodes and resistors for both protection (48V phantom power could damage the 3V micro-controller if gets there) and signal level adaptation.