Calibration
The Retrotrip2 has been designed for approval for use on many historic or retrospective rallies to fill the vacuum left by a shortage of mechanical tripmeters. Those competitors who could source a genuine period tripmeter with the correct functions and with sufficient spare parts to get it calibrated were felt to have an unfair advantage. The Retrotrip has the functions and instant 'one in a thousand' calibration accuracy for any wheel changes etc, plus can be seen to be 'fiddle proof' because of the old style electro-mechanical clicking digits, hence its' widespread approval.
The Retrotrip can be used with a wide range of motion sensors, but the universal speedometer cable sensor is the one recommended. See the separate sheet for correct connection to the grey cable. The black cable connects brown to +12 volts and the green/yellow connects to -12 volts, both of which should be directly to the battery terminals via a 2 amp fuse and not to chassis or existing vehicle power points. The highest quality connections are needed (definitely not crimps!). Cars not using the modern negatively earthed alternator type charger should use the Brantz Power Conditioner to get a reliable power source. Failure to do this can cause counter mis-match. Calibration: To measure hundredths of a mile, set the rotary switches (they may have central button actuators which require pen-push operation) to 100 then go to the start of a measured mile. Zero the readouts. Drive exactly a mile at no more than 20mph and stop. Note that there is a limit to how fast the readouts can step, and this can easily be exceeded during calibration although this will not be a problem with the higher calibration figure derived and actually used later. The three digit figure which has accumulated during the mile should be entered onto the rotary switches. The mile should then measure as a mile. Trim the figure up or down a digit to optimize. The above procedure can be used to calibrate in kilometres, but substitute the word 'kilometre' for the word 'mile'. Carefully read the TROUBLESHOOTING documents to reduce to a minimum the shortcomings of the old technology which is the basis of the retrospective design. Testing a RetroTrip on the workshop bench. DEALER INFORMATION. (NOT) FOR RELEASE TO CUSTOMER. May 2000. Connect the power cable (black sheath) to a 12 volt battery, brown to +12 volts, green/yellow to -12 volts. Note that testing can not be done reliably when connected to a battery charger, as the current is not smoothed. If the Retrotrip has customer-installed connectors, especially crimp types, push & pull these gently, then firmly, to check tightness. Solder them in place wherever possible. Test (1) Switch on the Retrotrip. Observe the top lights go on. Switch off. Test (2) (Optional test for dealers with Brantz test equipment. Others go straight to test 3) Put the Retrotrip calibration switches (some may be pen-push types) to 555. Connect the grey cable to a Brantz 'Rolling Road Tester' taking care to connect the right colours. Zero the two readouts. Switch on the Retrotrip. Note the two counters click over together. Change the calibration figures (there is a limit as to how fast the counters can go, so the calibration figure cannot be too low. Switch off the Retrotrip. Remove the 'Rolling Road Tester'. Test (3) Connect a sensor to the grey cable carefully observing the colour codes (see the sensor information sheet). Select a low calibration figure. Switch on the Retrotrip. Rotate the sensor mechanism (or for a wheel sensor touch a steel object onto the tip of the sensor many times). See the counters click over. SELF TEST FACILITY FOR MORE RECENT MODELS: Connect the Retrotrip to a charged battery supply (sensor is not needed). Put the rotary calibration switches to 000. Turn on the power. Note the readouts take half a step. Within eight seconds of turning the power on, change the calibration switches to 888. After a few seconds the counters will start to self-step themselves in groups of eight for as long as the power remains connected. This enables the simulation of great distances on the bench. If all the above functions are correct then any problem is likely to be with the car and/or the installation. See the trouble-shooting tips on the sensor sheet and MOST IMPORTANTLY - try the meter on another car. Derive power directly from the battery TERMINALS not the chassis or fuse panel. This is the single most important installation recommendation, and it is the one most resisted by customers as it is frequently inconvenient. Low battery voltage at the trip will cause trouble (see recommended power conditioner below).
Popular problems are: Reversed power, loose crimp type connectors, even more loose connectors, battery under voltage, poor quality wiring with still more loose connectors, and earthing derived from chassis instead of battery, radio interference from HT/pumps/horn/wipers/dynamo/ alternator etc.
See sensor sheet for a very simple interference test.
N.B. PREVENT VIBRATION! - Excessive vibration can cause one counter to disagree with the other. Remember that the counter technology of the Retrotrip is necessarily over fifty years old and today's expectation of perfect performance is a little harder to achieve. Older cars with 6 volt electrics or poorly performing or less reliably performing 12 volts charger systems should use a BRANTZ POWER CONDITIONER which will always produce a correct voltage source for the Retrotrip.
GOOD LUCK !
Accueil 
