BEM PRODUCTIONS


Broadcast Television Services of Austin, Texas

Phantom power and RTS - Clearcom testers

1) Phantom power / DC voltage and polarity tester

Supplies: 3 pin male XLR connector, two mini red/green LEDs, two 1K resistors.

Step 1) determine which leg on LEDs are green and which are red by running DC current through them. Positive to negative is green in this discussion. The LEDs need to be marked #2 and #3 to represent the 2 and 3 legs.

Step 2) solder the 1K resistors to the green leg of each LED.

Step 3) Solder both red legs of the LEDs to pin 1 of the XLR

Step 4) Solder the green leg of the #2 LED to pin 2 of the XLR

Step 5) Solder the green leg of the #3 LED to pin 3 of the XLR

Troubleshooting notes: if the LEDs light red the polarity is reversed with leg one to the respective side. Leg #2 is considered the primary side and is for phantom power, IFB and intercom. Leg #3 is for Ch2 intercom but non interrupt IFB will not light the LED.

RTS and Clearcom tester notes:

You'll need to buy Radio Shack Part Number 277-1008C. It is a mini amplifier with female mini jack input and output plus a speaker. Cost is around $15.

Pin 1 = Shield for the microphone

Pin 2 = Hot lead for microphone

Pin 3 = Return for the headsets speaker

Pin 4 = Speaker hot lead channel 1 (both sides on 4 pin systems)

Pin 5 = Speaker hot lead channel 2

2) RTS (4 pin) headset tester

Supplies: 4 pin male XLR, mini amplifier (mentioned above), two male mini jacks and about 8" of shielded AWG 22 two pair wire.

Step 1) Input mini jack tip to XLR pin 2 and input mini jack ring to XLR pin 1

Step 2) Output mini jack tip to XLR pin 4 and output mini jack ring to XLR pin 3

3) Clearcom (5 pin) headset tester

Supplies: 5 pin male XLR, mini amplifier (mentioned above), two male mini jacks and about 8" of shielded AWG 22 two pair wire.

Step 1) Input mini jack tip to XLR pin 2 and input mini jack ring to XLR pin 1

Step 2) Output mini jack tip to XLR pin 4 and output mini jack ring to XLR pin 3

Step 3) make a jumper across XLR pin 4 and 5