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Item Description:

This auction is for one replacement power supply for the Sequential Circuits Prophet 5 Analog Synthesizer, Rev 3.0, 3.1, 3.2, and 3.3..

The board can be configured with the -5V and +12V regulators for Rev 3.0 or for any of the later revisions. Let me know which revision you need after purchase.

Each supply is tested with a 0.75A load on the +15V and -15V regulators and a 1.25A load on the 5V regulator. I use the MOLEX connector for the testing so I do not have to solder/unsolder wires on the board.

There may be parts not installed on the board. They are not needed for the Prophet 5.

The power supply uses the existing transformer in the Prophet. The power supply is assembled and tested. Pictures show the new supply board and an older version of the supply board installed in a Prophet 5 (not included). This is an updated version of the supply that has a linear post regulator for the +5V. All three of the regulators need to be mounted on the rear wall.

This supply is a new replacement that was designed to address the over heating issues that can occur with the original power supply when options are added to the synthesizer. It will also run cooler in a stock synthesizer. The rectifier diodes are rated at 3A. The filter capacitors are 35V or 50V depending on availability. This provides a minimum 10V margin over the original 25V parts. The linear regulators are rated at 1.5A. They are in a thermal plastic package so there is no chance of shorts from the tabs to the chassis.

The +5V supply uses a switching regulator that is set to about 8.7V. It is follower by a linear post regulator that provides the +5V. The +5V can be varied if needed up to about 6V. The +5V should be adjusted to match the voltage output from your original power supply, assuming it still functions.

The increase in voltage to about 5.8V (on revision 3 and later) on the original 5V supply was needed because there is a 1N4002 diode in the ground lead of the LM340T5 regulator and a matching 1N4002 diode in series on the main board. The original LM340T5 regulator had to dissipate over 17W, far too much to be reliable long term..

There is an over voltage protection circuit on the 5V output that disconnects the output when the voltage exceeds 6.5V.

There is a 4 pin MOLEX KK series 0.1 header on the left side of the board. The header can be used for add on boards. The header provides 5V @100mA and +/-15V @50mA.There is a PTC fuse in line on each voltage.

The silkscreen on the board shows the -5V and +12V for the Rev 3.0 supply. For Rev 3.1, those pads are not connected on the board. For the Rev 3.2 and later, the -5V becomes -22V and the +12V becomes +22V. Both have 5 ohm (nominal) resistors in line on the board. There are three pictures showing the Mini Fit pinout for all three versions.

Installation:

Before removal of the old power supply, measure/record the voltages and mark the wires so that they can be connected to the proper terminals on the new board.

1. The old board and the capacitor clamps must be removed.

Also, remove the three regulators from the back panel (if there).

Four 1/8" (0.125") mounting holes will be needed in the bottom of the chassis as this supply is not attached by

clamping the filter capacitors. The mounting hardware is included. The standoffs are swaged/soldered to the

board. The board can be used as a template for marking the hole positions by using a nail that fits through the

standoff to mark the centers of the holes. Dimensions for the hole locations are also in the silkscreen on the

back side of the board. Attaching the installed 5th standoff in the middle of the board is optional.

2. The three TO-220 packaged regulators are mounted using the same holes as the originals if they were mounted

on the rear panel. New sil pads are included. The new regulators do not need the plastic shoulder washer, the

tabs are not electrically conductive but are thermally conductive. Re-use the original screws.

3. Connect the three AC leads from the original transformer to the screw terminal block.

The transformer center tap is in the center terminal. The other two wires can be connected to either side.

4. Once the board is mounted and the AC power connected, the supply can be tested/adjusted.

The -15V supply is now a fixed regulator. Adjust the +15V to match the -15V level.

Adjust the +5V supply to match the voltage measured from the original supply.

5. With the Prophet OFF and unplugged, the output wires can be connected. The DC power connection pads

are located in about the same locations as on the original board.

The wires will need to be un-soldered from the original board and soldered to this board or they can be

crimped to pins which are inserted in a MOLEX Mini-Fit Jr Connector Housing (housing and pins not included)

if you want to make use of the on board connector.

The eight pin MOLEX Mini-Fit Jr connector on the board has all of the required voltages.

This can be used if you have the ability to crimp the output wires to the mating pins/housing (not included).

If using the Mini Fit Jr connector you will need one MOLEX 39-01-2080 housing and eight female pins 39-00-0039

for each board. Pictures of the pinout (top view) showing the voltages for each revision are in the listing.

6. That should be it. Make adjustments to the +5V and +15V if needed now that the wires are connected.

Basic installation instructions similar to those in the listing will be provided, but the user must be capable of un-soldering and soldering wires, optionally crimping wires, drilling holes, and basic mechanical assembly. Be sure to measure the original voltages and label the original wires for voltage so there is no confusion when connecting them to the new power supply. Feel free to contact me through EBAY for additional information or questions. It may take 24 hours or so for a response, I usually do not get online until evening.

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 or international via the EBAY global shipping program.