Exogal Comet Quick start guide

Replacing the Power Umbilical in the EXOGAL Comet Power Supply Upgrade
The cable is easily replaced by the user.
Unplug the power supply from the AC power and remove the DC plug from the back of the Comet.
The umbilical can be replaced by simply removing two screws from the back panel (cord side) of the
Power Supply and the screw located on the bottom of the unit. Pry off the rubber feet on the back panel
side of the bottom of the Power Supply. Be careful not to set the feet adhesive-side down on a piece of
paper or another porous surface!!

Remove the screw in the center of the housing on the bottom of the Power Supply using a 1/16” Allen
wrench.
Using a 1/16” Allen wrench, loosen two set screws approximately 2-3 turns. It is not necessary to
remove them completely.
Pulling gently on the back panel, slide the power supply board out of the housing.
There is a green terminal block, designated “J101”. The location is shown below on an un-populated PC
board (for clarity).

The terminal block is 3 positions, pin 1, towards the board edge, is Ground (GND). Pin 2 is unconnected
and must be left unconnected. Pin 3 is the +15 VDC terminal.
Loosen the Cable Gland by turning the knurled knob counter-clockwise until the cable slides freely.
Using a small flat blade screwdriver, unscrew and loosen terminals 1 and 3 on the terminal block J101 to
release the wires. The Brown wire is +15 VDC and goes to terminal block J101, terminal 3. The Black wire
is Ground (GND) and is connected to terminal block J101, terminal 1. Remove the wires from terminal
block J101 and pull the cable out of the chassis.
Push the new power cable through the cable gland, from the outside to the inside. Leave it loose until
the wire is attached to the terminals. (We use the heat shrink tubing to protect the cable from the cable
gland. This is optional if you are replacing the cable with one of your choice.) Strip no more than ¼” of
insulation from your wires and insert the wire you use for +15 VDC to pin 3 of terminal block J101.
Tighten the screw firmly. Insert the wire you use for Ground (GND) to pin 1 of terminal block J101.
Tighten the screw firmly.

Pull the excess cable slowly back through the cable gland, leaving a small amount of slack as shown in
the picture above. Tighten the cable gland to secure the cable.
Prior to reassembly, ensure that the light pipe is firmly seated on the Power Supply board so that it will
mate properly with the hole on the front panel. (If you skip this step, you may not see the power
indicator on the front of the supply!)
Reassemble the chassis by gently sliding the printed circuit board / back panel assembly all the way into
the housing and then press the back panel firmly into the housing ensuring that it is fully seated. (You
may need to wiggle the board up and down a bit to ensure it seats properly.) Ensure you can see the
light pipe through the front panel hole.
This: not this:
(It will be apparent if it is not mated properly and you will see an empty hole!) Secure the set screws
hidden under the feet. Reinstall the screw on the bottom of the supply as well. Once the screws are
tight, reattach the rubber feet.

Original Umbilical Parts List
5’ 3” Cable, Lapp Tannehill U302202 Oleflex, 22 AWG, 2 conductors.
5.5mm (outer conductor) x 2.1mm (inner conductor) x 10mm (connector length) DC Power Connector
¼”, 3 to 1 Heat Shrink Tubing (protects the cable from the cable gland)