Bose Companion 5 Satellite Speaker Connector Replacement

Perhaps you, like me, have a Bose Companion 5 main unit but not the satellite speakers. The satellite speakers use a proprietary connector and Bose disappoints with no parts support. I noticed the connector is close in size to the Molex Mini-fit Jr connectors used for PC power supply motherboard connectors. It turns out that the Mini-fit 2x2 jack fits the Companion 5 box with minimal effort.

I found only one other Bose Companion 5 Instructable: Bose Companion 5 Speakers Extention Cable.

Parts

• Molex Mini-Fit Jr 4 Pin Connector (Pitch 4.20mm, w/18-24 AWG Pins/Sockets) - sourced from eBay
• Inline RCA Audio Jack Connector (four) to make speaker cable adapters - sourced from eBay
• hook-up wire in various colors - sourced from spares
• heat-shrink tubing - sourced from spares

Tools

• soldering / desoldering station
• wire cutter / stripper
• cable crimper with small die
• ruler
• small rotary cutter (Dremel) with small round bit and cut-off disc
• small suare, triangle and flat files
• scalpel or small hobby knife

The Bose Service Manual provides steps for removing back panel from the Companion 5 case (four screws) and pulling out a circuit board.

The plastic back panel needs to be removed as a separate part for trimming openings to fit the new jacks.

A plastic retaining cage for the connector circuit board needs to be removed as a separate part for trimming to fit the new jacks.

The connector circuit board needs to be removed as a separate part for removing the old jacks and enlarge a hole for new wiring.

The details of this procedure are covered in the Service Manual, starting on Page 17.

The red and while speaker jacks, J3 and J4, need to be de-soldered and removed from the circuit board. I have a nice Weller de-soldering station to remove the old solder so the two parts practically fall out on their own. It may be a little tricky with just a fine soldering unit, with four pins to get loose at once. Note the solder is the newer no-lead type, so a hot iron is needed to melt it and a quick hand to pull the part before the solder re-solidifies.

The Molex Mini-Fit Jr jacks are designed for panel mounting in a square hole with two slots on the sides for the retaining clips. This is just a little larger than the existing holes.

I used a combination of Dremel tool with 3/16" round cutter, small square, triangle and flat files to open up the corners and add the slots on either side of the openings. Some of the supporting rib on the inside of the panel needed to be cut away as well.

Somehow, the photo make the trimmed areas look fuzzier than they are in real life. I actually trimmed the edges much tidier than it looks, using a scalpel to remove the rough edges.

The circuit board retaining cage runs through the space needed by the new connector housing.

The simplest approach would be to simply cut away the offending bits wholesale to clear the housings. I started with a minimalist trim to just clear the housings. This turned in to a lot of fussing with a little trim here and a little trim there to get the cage to clear. This is shown in the photos. The affected areas turned out rather thin in the end. In hindsight, I should have just done the simple approach of cutting out the plastic completely.

Because there will be no clearance between the new jacks and the circuit board, the speaker wires will be routed to the underside of the circuit board. There is an unused hole in the board that can be enlarged to allow the eight wires to pass through. You can see the circuit traces on both sides of the board by holding it up to a light; this will reveal the unused area around the hole that can be enlarged to a slot.

I used the 3/16" diameter Dremel bit from the rear panel trim for this. It wasn't really happy cutting fiberglass, but did the job fine. The cutting edges just look a bit dull now but still continue to trim plastic. The first photo shows the new slot to the left of the large black power connector, J1.

The second photo in this step shows the final fitting of connector housings and circuit board to the rear panel. Note the housing rest flush against the circuit board.

The original speaker jacks are opaque how the four pins are organized. Fortunately, a schematic for the Companion 5 is available on the web. It reveals the satellite speakers have two channels; a basic side channel and a surround sound channel.

The included, "bose-companion-5-io-bose-pcm-top-and-bottom-board-layout" is the key for figuring out wiring the new connectors. My notes decoding the new wiring on in "note-1" and "note-2".

The included, "bose-companion-5-dsp-schematics", was also useful for confirming the four speaker channels. "bose-companion-5-dsp-bose-pcb-top-and-bottom-board-layout" is for the main Digital Signal Processing board, not really relevant to this exercise but included for completeness.

The easiest way to get the tidiest routing is to prepare the circuit board with excess wire length, then trim to fit with the jacks and board fitted.

1. Cut eight 22 ga wires, colors
2. Strip 1/16" from one end of each wire
3. Solder each wire to underside of board. I heated the joint from topside and placed a small drop of solder to secure. The goal is to have nothing extend above the board to interfere when the connector housing sit against the board. The first photo shows how I used a small stand to hold the board and wires in position for soldering.
4. After completing all eight wires, route through the slot in the circuit board and test fit the board for final wire routing. With connector housings in place, push the wires through the housings (no pins) with the excess wire protruding. (Shown in last photo)
5. Trim each wire flush to the outside of the housings (not shown). This sets a basic reference length for each wire.
6. 
   

To complete the wires, cut them back 5/8" from the lengths prepared in the previous step. This accommodates how the pins sit in the housing. The photo shows how this was determined, matching how the pins sit in a reference PC power jack.

1. Trim 3/32" of insulation from free wire ends
2. Solder wire to pin with a fine soldering tip and the least amount of solder to attach. The goal is to just secure the wire for crimping without adding bulk to interfere with the crimp compressing against the wire.

Finish assembly of pins into the connector housings following the diagram.

This completes construction of new parts.

With the new work complete, prepare the rear panel for reassembly.

1. USB connector into rear panel
2. Circuit board into rear panel clips
3. Molex jacks into rear panel openings
4. Circuit board cage over circuit board and attach three screws
5. Bass control knob over shaft

As expected, this is reverse of disassembly and follows the Bose procedure.

• verify connectors
• data connector, J22
• speaker connector, J21
• power connector, J2
• USB cable between rear panel and connector J8000 on DSP board
• set rear panel in place and replace four screws

I didn't have a specific speaker set-up in mind when I started this project so I make up a pair of generic adapters to RCA jacks to go with the numerous RCA speaker cables I seem to have acquired. I had to buy the inline RCA connectors but used some 18 gauge wires from the PC parts bin. This is how I made my adapters:

1. Cut eight three-inch wires:
2. two red
3. two yellow
4. four black
5. Connect wires to RCA jacks
6. solder black wire to shell
7. slip short heat-shrink to cover soldered bit from center
8. solder red/yellow to center
9. cover whole innards with an inch or so of heat-shrink to cover center from shell
10. screw on outer cover of jack
11. add short bit of 3/8" heat-shrink to color code RCA jacks (I used red for center, yellow for surround, based on heat-shrinks I had on hand)
12. Twist each pair of wires and trim all wires to make adapters the same length
13. Attach a Molex connector socket to each wire with a small bit of solder. (minimum possible to hold wire until crimping)
14. Crimp sockets to wires
15. Insert wires into plug housing, following mirror image of jack connections
16. red for side channel
17. yellow for surround channel
18. black for corresponding negative returns

Hint: I was rather casual making these adapters and made both the same. As I made up the nice version of my hand-written notes for this article (Step 6), I remembered speaker connectors J3 and J4 do not have the same arrangement of pins for side and surround channels. I should re-pin and label my adapters to be specific to the two sides to ensure all four speakers get connected properly. Being forewarned, you can do the job properly from the start.