The expansion connector is an optional extra. It can be used for two main purposes

1. Double-heading miniature locomotives.
2. Adding a tacho feedback loop

The expansion connection fitting is different for these two purposes. This page expains the changes.

Both fittings require some soldering to the board (removing a surface-mount component and fitting through-board connections) so fitting should only be done by the technically proficient. It is however not difficult!

4QD will not however be responsible for the results if mistakes are made in fitting the connector!

Fitting the connector and modifying

The 6 way Expansion connector fits as the diagram above. This also idenfifies the points A, B, C and D - these must be linked through from top to bottom of board (for double heaing) by threading though the board a piece of tinned copper wire. This must be soldered on both sides. The bottom points of these connections are further identified (on the second diagram) by red dots. A is linked as standard and should not be altered..

Double heading

1. Fit 6 way connector
2. fit 3 though links, B, C and D.
3. Remove LK2 (this removes +9v from pin 1, which becomes the ignition common)

Tacho

1. Fit 6 way connector
2. Remove LK3 (this disconnects the ramp output from the modulator input).

Notes on Tacho modification

• When the tacho modification is fitted, the controller will not work without the tacho board in place. If operation without the tacho board is required, pins B and C must be joined.
• If the tacho generator is disconnected, at a pot speed setting sligtly above zero, the controller will accelerate to full speed. If the pot is again z\eroed, the motor will be decelerated to zero.

The connector set can be supplied for customer retro-fitting:

Price List

Description	Order Code	Price List	Add to cart
Expansion connector kit for VTX	NXC-006