Pro-120 Mk2

Internal Power Supply and Protection Circuitry

The Pro-120 and Scoota series controllers have some sophisticated internal power supply circuitry which includes reverse polarity protection, pot fault detection and high pedal lockout. This is a description of the features and of some Read More

Pro-120 Mk2 History

In early 2003 we released a redesigned Pro-120 controller. However – in general it’s such a popular and good controller that not a huge redesign was possible. The main change is that it uses sub-miniature Read More

Pro-120 Key Components

The Pro-120 series are card controllers, open to the elements – and users. They are similar to the VTX and older NCC series – but have several more sophisticated protection mechanisms built in. This page Read More

Earth Fuses: Why Do They Blow?

This page deals specifically with the Pro-120, but other controllers have a fuse in the earth, or can blow a pot earth connection. This page explains how. Wiring faults can cause the fuse in the Read More

Modifying the Pro-120 for other voltages

All controllers made by 4QD are generally wide voltage operating range: limits are the operating voltages on the MOSFETs and the relays, and the power dissipation in the current source transistor used for the internal Read More

Pro-120 Fault Finding Tips

Faults on the Pro-120 series are not common, but there are a few which occur, mainly because the ‘bare board’ style of the controller makes it susceptible to certain abuses. These fault finding tips may Read More

PRO-120: Multiple Slaves

This applicaton note applies to Mark 2 Pro-120 controllers only. The Pro-120 has an expansion connector that may be used to connect a master controller to a single slave. Connecting to more than one slave Read More

PRO-120 Ramp Reduction

The Pro-120 series acceleration and deceleration ramps are adjustable down to as fast as about 330mS. It is possible to reduce this timing but any modifications should be done with extreme caution. The ramps are Read More

Fitting Expansion Connector

Pro-120, VTX and NCC series controllers. Retro-fitting expansion connector Contents, this page Introduction Mark 1 / Mark 2 mixes VTX Pro-120 NCC Double Heading Tacho feedback board Solder Side All Controllers Additional controllers Older issues Read More

Pro-120 Robot Wars Version

The Pro is available in two versions, the standard version and the -RW version. This page explains the differences. Input decoupling There is, on the input to the standard controller, a noise decoupling circuit – Read More

Pro-120 Ignition Options

The Power relay drive circuit on the Pro-120 can be factory configured in three different ways. This page explains them. The power relay is switched on and off by a transistor that detects the internal Read More

Wiring for Push Button Use

This diagram shows how to connect a Pro or DNO (or earlier NTX and NCC) series controller for push button use, or with a centre-off switch. Note that the diode shown between the buttons must Read More