XB2-Kit mk3 Installation

Installation in Hammond XB-2

This page covers the new HX3 mk3/mk4 retrofit kit for XB-2 with stereo Leslie simulation. For older kits (no longer produced), see here: Installation in Hammond XB-2 (old HX3 kit) (use for reference only!)

Installation in Hammond XB-2 may be performed by any skilled person within 1 or 2 hours; no soldering required. Please click on picture to enlarge. Please also regard user manual on XB2-Kit mk3 User Manual.

Your XB2 Kit is equipped with the new HX3 mk3 Board with stereo Leslie® simulation and configurable audio output jacks. On factory default, internal Leslie simulation is enabled. For use with external Leslie, push “Edit Fuction” button and then “External Leslie” button. Push again to select external Leslie ON. Configuration will be saved to internal non-volatile (D)efault memory if button is pressed again for 1sec. With external Leslie enabled, audio jacks carry plain organ signal on LEFT and bass pedal signal on RIGHT jack. All outputs are mono. Both are routed through the internal Amp122 overdrive, controlled by the Amp122 gain pot. This is ideal for connecting transistor Leslies to get a warm tube distortion. Function of Amp122 pot is same as volume pot on Leslie tube amp chassis.

Drawbars are routed automatically to manual played (when split is ON or external keyboard connected on MIDI channel 2). You may further select drawbar routing by ORGAN SOLO button (LED lit up = upper keyboard to drawbars).

Audio output jack board is now equipped with treble/bass control which works like original XB-2. Pots are on same position as before. Please re-use old pot knobs from XB-2 board.

We recommend a volume swell/expression pedal like Yamaha FC-7 or similar. Sorry, you may not use your Hammond swell pedal anymore. Bass/Treble equalizer knobs (not supplied) may be re-used from old XB2 audio board. Single footswitch may be connected to the original "FOOT SWITCH" jack, dual footswitches or halfmoon switches with "Stop" position should use the new "FOOTSW" connector next to swell pedal jack.

Remark: Early XB-2 do not have the "Reverb" pot on right (and no built-in reverb, either), so there is no "Amp122 gain" pot after installation (one 5-pin header and 8-pin header on output jack board remain open). An optional pot may be connected to PL52 according to schematics.

Open XB-2 by loosening 5 big screws on bottom. Remove keyboard by loosening 7 medium sized black and brass screws on bottom and inside organ. Disconnect keyboard from mainboard plug connector. Remove nylon wire straps on cable harness, but DO NOT cut any cables, just unplug all connectors! Keep MIDI jack board. All other XB-2 boards may be discarded (or sold for big $ on ebay).

Remove all boards inside including supporting rails. Retain cables and headers from power supply, front panel, drawbars, LCD and volume/reverb pots. Locate pink/black/green/orange strain and separate black/white strain to now unused connectors. Obsolete XB-2 power connectors may be cut off as pictured here or may be left open and tied up securely (see next picture). Insulate cut wires with shrink tube. DO NOT cut long orange/black/green/black/yellow cable!

Install HX3 mk3 mainboard and tall LCD/scan interface board as pictured using wood screws and 5mm plastic spacers supplied with kit. Be shure all cables reach their connectors; black drawbar ribbon cable may be pulled out a little.

Connect black drawbar cable, large 5-pin power plug, LCD 14-wire, Pitch/Modwheel 4-wire and coloured button cables to matching connectors on tall LCD/scan interface board as pictured. XB2 connectors are all different size and cannot be confused. Connect short 10-wire and 16-wire flat ribbon cables exactly as pictured. Note different orientation on two rightmost cables. Obsolete power connectors may be left open and tied up with wire straps.

Re-install keyboard and connect to 15-pin header on tall LCD/scan interface (right side). Be shure not to pinch any cable. If supplied with 2-pin green power connector, wire yellow cable from power supply to screw terminal marked "+5V" on HX3 mainboard, black cable to other screw terminal.

Install new audio jack/preamp board board as pictured. Connect long orange/black/green/black/yellow cable to matching 5-pin header on jack board. Connect gray and red/brown/white cable connectors to matching headers on jack board (see remark 1 above). Connectors are mostly different size and cannot be confused. Connect 20-pin flat ribbon cable to HX3 mk3 main board and jack board.

Re-install MIDI jack board and connect to 12-pin header on jack board, left side. Install long 3-wire cable (35 cm) from jack board PL50 FOOTSW to HX3 mainboard PL19 FWS connector. Install other 3-wire cable (30 cm) from output jack board PL48 CONTR to tall scan interface board PL60, 3-pin connector. Affix al loose wires by nylon wire straps as shown.

Connect Leslie 11-pin connector to matching header PL45 on jack board (right side). Plug in organ and test all functions. Volume for Leslie Bass and Rotary channels may be adjusted by trimpots on audio jack board, if necessary.

Attach decals and lettering on front and back of organ. Note for alignment: Headphone jack is on same position as before. Plug in organ and test all functions. Re-install top lid. Now you're done!