8Viper2500s11 Power -on indicatorIndicates that the Viper is receiving power from the power source it is connected to.12 Warning IndicatorIndicates that the Viper is connected in reverse polarity, i.e. the positive lead from the power source is connected to thenegative in terminal on the rear of the Viper and vice-versa. The set will not operate in this condition.13 Thermal cut-out IndicatorIndicates that the thermal cut-out in the machine has operated. (see paragraph 5.1 in the fault finding and mainte-nance section for possible reasons) control to set the desired welding current, the digital display will indicate the setting.14 Gas out connectorThis is a female quick coupling with an internal shut- off valve.To connect, push the male connection on the end of the TIG torch adaptor into the coupling until you hear a click. Tofully disconnect, push the knurled ferrule on the connector inwards towards the Viper until it stops.The shut off valve in the connector automatically closes when the connection is separated.15 Positive out connectorMain welding power output connector, positive polarity.16 Negative out connectorMain welding power output connector, negative polarity.17 Positive in connectorMain power in connector, must be connected by welding cable to the positive terminal of the power source.18 Negative in connectorMain power in connector, must be connected by welding cable to the negative terminal of the power source.19 On/Off switchSwitches the Viper on and off.20 Fuse HolderHolds the main protection fuse for the Viper.21 Gas In connectorMust be connected to the pressure regulator on the gas cylinder by means of a suitable hose.22 Remote control socketFor connecting external remote control units, these are the RC300 remote control, the RPC300 pulse unit and the RFP300foot pedal. There is no switch for remote operation, plugging an external unit into the socket automatically selects re-mote operation and disables the internal current control.4.2 Operation4.2.1 MMA Operation• Connect the Viper as per paragraphs 3.2 of the Installation section.• At the power source, turn the power on and the current control to maximum.• Turn the TIG/MMA switch on the front panel to the MMA setting.• Press the On/Off switch on the rear panel to the on position, the power on indicator and the digital display will lightand the Viper is ready to use.• Turn the current control to the setting required for the task in hand.4.2.2 TIG Operation• Connect the Viper as per paragraphs 3.2 of the installation section• At the power source, turn the power on and the current control to maximum.• Turn the TIG/MMA switch on the front panel to the TIG setting.• Turn the TIG2/TIG4 switch to the desired mode of operation.• Press the On/Off switch on the rear panel to the on position, the power on indicator and the digital display will lightand the Viper is ready to use.• Turn the current control to the setting required for the task in hand.SECTION 4 — OPERATION AND USE