eBay

Item Description:

This auction is for one replacement power supply for the ARP Pro Soloist and Pro DGX Synthesizers and other ARP synthesizers that require a +5V, +15V, and -15V power supply. This supply is a new replacement.

There are different cables used on revisions of these units. Prior to purchase contact me and send the cable length and a somewhat closeup picture of the end of the cable that plugs into the main board. If possible with it plugged in. I need to verify colors to try to match your original colors if I can.

The bridge rectifiers are rated for at least 2X the required current. The filter capacitors are larger value and rating than the originals. The voltage regulators are also rated for more than 2X the required current.

This power supply has the same low noise switching regulator for the 5V output as my Prophet power supply. This eliminates the hottest part on the old power supply bracket/heatsink, the 5V regulator. The 5V output also has over voltage protection fixed at about 5.6V. A FET is used to disconnect the output in the event of a fault. A red LED on the board indicates a 5V fault if it is ON.

The -15V regulator is an L7915CP 1.5A negative voltage regulator and is not adjustable.

The +15V regulator is an LM317P 1.5A adjustable regulator. Adjust the +15V output to match the -15V output.

There are no instructions included with the board, all instructions needed are in the listing.

This power supply is assembled and tested and adjusted for proper voltages with typical loads. Pictures 1 top 3 show the new power supply board. You will need to re-use the bracket from your old power supply, it mounts on the right side under the regulators. Picture 4 is a diagram of the power and switch connections. The wire colors in the picture are from the manual and from pictures of the PRO DGX. A new output cable (Picture 5) is included with the power supply that mates with the original connector in the PRO DGX. This eliminates the need for soldering. This cable uses TRIFURCON contacts on the mating end. These contacts have three mating surfaces for greater reliability.

The installation instructions below and the pictures in the listing should be adequate for the install, no other instructions are provided. The user must be capable of electrical measurements (voltage and resistance (shorts), drilling holes, and basic mechanical assembly. While not usually required, the user should also be familiar with un-soldering and soldering components or wires and optionally crimping wires to FASTON terminals.

There are depopulated parts on the board for other applications.

Feel free to contact me through EBAY for additional information or with questions. It may take 24 hours or so for a response, I usually do not get online until evening.

Assembly instructions follow...

INITIAL CHECK

Before starting the power supply installation, verify that the power connection on your unit matches the one in picture 6. If it does not match you may have an older unit, contact me prior to purchase to insure the correct cable is supplied.

There is no keying on the original connector on the board so you have to be very careful when plugging it in. A keyed mating connector, MOLEX P/N 26604060 (not included) is available from Digi Key or Mouser if you are up to un-soldering the original pins and installing the new connector. Use the new cable's mating end to get the orientation correct. It may be a tight fit due to the three capacitors close by.

BRACKET ASSEMBLY

The bracket from the original supply will be mounted in the same location in the synth as with the original supply. Remove the screws from the two voltage regulators to release the two spacers and put the spacers aside. They are not needed for final assembly. Two SIL pads are supplied with the board. The sil pads are slightly tacky and should be placed on the bracket with the tacky side towards the bracket.

The two regulators use a thermally conductive plastic package with thermal specs similar to the metal tab TO-220 regulators. The plastic package prevents shorts between tabs when mounted.

The bracket rests on the top of the PCB just like on the original power supply. You may have to drill new holes for the regulators in your bracket, use the board as a guide to mark the locations. Slide the bracket/sil pads under the regulators and attach the bracket to the board using the supplied screws and nuts that held the regulators in place. Do not use the original screws/nuts on the regulators. Leave the screws just loose enough to move the bracket by hand if needed. Make sure that the bracket is square to the board and not contacting the regulator leads. If the sil pads are not square to the regulators adjust them now. The screws holding the regulators in place can now be tightened. Place the original center screw through the center hole in the bracket and fasten it with one of the original nuts.

MOUNT THE SUPPLY TO THE CHASSIS

The power supply is not shipped with the four standoffs and mating screws. Use the screws and standoffs from the original board. The user will have to drill four 5/32 holes for the #6 screws. The 7th picture is the dimensions for drilling the holes. Use the bracket center mounting hole as a reference. To verify before drilling, attach the bracket to the original mounting holes on the panel about half way up the slot and see if the marked locations line up with the standoffs on the board. If everything lines up, remove the power supply board and and drill the holes. Use the standoffs and screws to mount the board to the chassis. The holes may be increased to 3/16 if a little repositioning is needed. Loosening the screws on the other side of the standoff can also help. Mount the bracket to the chassis with it's screws and nuts.

If not used with the bracket (in a different synthesizer), two additional standoffs need to be used on the bracket end of the board. The two regulators will have to be extended (using wires) so that they can be mounted to the chassis of the synth. Contact me before ordering if this is needed.

AC WIRING

If you are not familiar with AC wiring, have a professional install the power supply for you.

The line cord will have to be inserted farther into the chassis to use this power supply as the new board is shorter than the original (3"x7.5" vs 3"x12"). This can be done by releasing the line cord clamp and repositioning it to provide the extra length. It can then be re-inserted into the chassis. This would be a good opportunity to replace the cord with a new one.

The original FASTON connectors will mate with the FASTON terminals on the board, but as they are not insulated, they must be covered with heat shrink tubing or replaced with insulated FASTON connectors.

The new power supply as shipped is configured for 115VAC, but can be reconfigured for 240VAC. Contact me prior to purchase if you need a 220V/240V unit. The fuse is 1/4 amp.

Make sure the power cord is unplugged (I hate to have to state this but)...

The power connections are made using the FASTON terminals in the AC INPUT area on the board. Connect the power cord LINE wire (Black or Brown) to the LINE FASTON terminal. Connect the NEUTRAL wire (White or Blue) to the NEUTRAL FASTON terminal. The Green/Yellow (or Green) wire must be connected to the same point on the chassis as before, it is the earth/safety ground.

The switch connections are made to the FASTON terminals in the SWITCH area on the board. The same switch connections can be used for 115VAC or 240VAC. A switch with an integral 115VAC neon bulb and resistor (like the original switch) may be used. The power supply board connects the NEUTRAL to the bulb when configured for 115VAC and 1/2 the voltage from the transformer center tap when configured for 240VAC.

The power supply board has three connections for the switch, Line, Switched (Line), and Lamp-N which is the NEUTRAL connection for the lamp. See picture 4 for the proper connections (wire colors) when using the original switch.

CHECK VOLTAGES

Once the supply is installed and the AC connections made, the initial checkout may be done. With the far end of the output cable disconnected, apply power (plug in the power cable and turn ON the power switch) to the power supply. The three green LEDs on the board should be ON. If they are not ON, turn OFF the power and troubleshoot the wiring. With the power supply ON, measure the voltages at the far end of the output cable to insure that they are the right voltages and they are in the correct locations on the connector. The power supply will be OK without the load. Turn OFF the power when done.

Do not use the supply if the voltages are not correct or are not in the correct connector locations.

FINAL CONNECTION

With the AC power OFF (and/or unplug the power cord), and if the voltages checked out correctly in the previous step, connect the cable to the main board in the OMNI. Remember, the wire colors on the new cable must be in the same locations as the wire colors in the original cable when it is plugged into the main board power connector.

Once connected to the main board in the synthesizer, turn ON the power. The OMNI should be up and running. Measure the voltages at the synthesizer end of the cable and make a small adjustment if needed. Adjust the +15V, to match the absolute value of the -15V output (as close as you can). Adjust the +5V to output to measure between 5V and 5.2V.

That's it...

PayPal Confirmed Address: PayPal address must be confirmed and must be the same as the shipping address.

Returns: Returns are accepted for this item. Please notify me of any issue within 30 days of receipt of the item.

Feedback: Feedback is important to me, please email or contact me with any concerns, issues or problems before leaving feedback and give me the opportunity to work things out if needed. I always leave positive feedback after receiving feedback from the buyer, that way I know the buyer is happy and the transaction is complete.

Shipping : Shipping is direct to USA only. The board is not RoHS compliant so there is no international shipping.