Border Patrol Power Supply Installation Instructions.

Model: Audio Innovations series 500.

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ELECTRICAL KNOWLEDGE IS REQUIRED IN ORDER TO PERFORM THIS CONVERSION SAFELY. POTENTIALLY LETHAL VOLTAGES ARE PRESENT. WE CANNOT BE HELD RESPONSIBLE FOR ANY ERRORS THAT MIGHT ARISE WHEN PERFORMING THIS CONVERSION. IF YOU HAVE ANY DOUBT ABOUT YOUR ABILITY TO PERFORM THIS CONVERSION SAFELY PLEASE CONTACT US FIRST.

PLEASE READ THE INSTRUCTIONS FULLY BEFORE COMMENCING

KIT CONTENTS.
POWER SUPPLY, 4 WAY TERMINATED CABLE, RUBBER GROMMET, CABLE GLAND HEAT-SHRINK, CABLE TIES.

TOOLS REQUIRED.
SOLDERING IRON, PLIERS, M4 ALLEN KEY, SCREW DRIVER, SOLDER, ELECTRIC DRILL, 10mm BIT.

DISCONNECT THE AMPLIFIER FROM THE MAINS BEFORE BEGINNING. If the unit has been used recently, allow sufficient time for the power supply capacitors to discharge before beginning (5 mins is usually sufficient).

REMOVE THE VALVES NOTING THEIR POSITION.

This is a two stage conversion. The Stage 1 disables the on-board high voltage supply and connects the new off-board supply. Stage 2 enables the relay to switch the new supply on and off from the existing on-off switch.

Remove the 4 Allen bolts securing the lid and lift the lid carefully from the rear. The lid cannot be completely removed but sufficient access can be gained to perform the conversion. Find a suitable object to prop up the lid in order to complete Stage 1 ( a 20cm prop is required).

Stage 1.
Depending on the age of the unit, a green printed circuit board (PCB), or two large electrolytic can capacitors connected via a 47-220 Ohm 50Watt metal-clad resistor, will be positioned next to the mains transformer.

PCB version. Locate the Bridge Rectifier (a black plastic rectangular object with four metal legs) mounted on the PCB next to the mains transformer.

Whichever capacitor this is located above will be referred as Cap1. The other capacitor which is connected to the output transformers will be referred to as Cap2. Remove the four stainless steel screws which secure the board to the capacitors. Locate the 47ohm ceramic dropper resistor, de-solder it from underneath and remove it. Cut the two Red wires that come from the mains transformer to the Bridge Rectifier and insulate their ends with the heat-shrink provided. Do not remove or damage any of the other wires leading to and from the board. Re-fit the board using only the screws for Cap1. Drill a 10mm hole for the rubber grommet or a 13ml hole for the cable gland in either the underside or the back of the unit. Fit the grommet or gland. You may find an existing hole that can be enlarged on the bottom of the unit.

Be careful not to damage any internal components whilst drilling. Feed the supplied cable through the hole and secure in place with the cable ties provided. Feed one of the left over stainless steel screws through the circular tag on the RED cable, through the PCB hole marked positive (+) and into the terminal of the Cap2. Repeat for the GREEN cable with the circular tag through the PCB to the negative (-) terminal of Cap2. Screw down tightly ensuring that the tags do not touch each other. You have completed the attachment of the High Voltage supply. Hard-wired version.
Locate the H.T. Bridge Rectifier (a black plastic rectangular object with four metal legs) mounted on one of the Electrolytic capacitors. Whichever capacitor this is located above will be referred as Cap1. The other capacitor which is connected to the output transformers will be referred to as Cap2. Locate the 47-220ohm dropper resistor which connects the +ve terminals of the two caps and remove it. Cut the two Red wires that come from the mains transformer to the Bridge Rectifier and insulate their ends with the heat-shrink provided. Drill a 10mm hole either in the underside or the back of the unit and fit the rubber grommet supplied. You may find an existing hole that can be enlarged on the bottom of the unit. Be careful not to damage any internal components whilst drilling. Feed the supplied cable through the hole and secure in place with the cable ties provided. Screw the circular tag attached to the red cable into the Positive terminal of Cap2 (this terminal was previously connected to the resistor) Make sure that all previous connections to this terminal other than the resistor are left in position.. Repeat for the GREEN cable into the negative (-) terminal of Cap2. Screw down tightly ensuring that the tags do not touch each other. You have completed the attachment of the High Voltage supply.

Stage 2.
Remove the bottom panel. Locate the 4700mF/16V (or similar) electrolytic capacitors on the main PCB. Feed the blue and brown leads from the back of the unit and solder the blue lead to the positive terminal (marked +) of the capacitor and the brown lead to the negative terminal (marked either - or with a black band). This completes the connection to the relay inside the off-board supply.

DANGER. Check that the two circular connectors on the High Voltage supply are not touching each other.

Dress the new cables tidily and replace the lid. Replace the valves and the on/off switch and connect the umbilical lead to the new o-board supply. Replace the mains lead to both units. Switch on the Audio Innovations amplifier as usual. Your amplifier should now be ready to play. The valve supply will take longer to come up to operating voltage than the old supply but this will have the advantage of lengthening the life of the valves.

BorderPatrol Audio Electronics
c/o Kaja Music Systems   Waldorf  Maryland  USA

Phone/Fax +1 301 705 7460
E-Mail. bp@borderpatrol.net