Display data receiver adjustment procedure for TouchLine stations

TochLine station display data receiver adjustment procedure

This procedure describes the adjustmet of the receiver in the TouchLine display stations based on the Motorola 68HC05 microcontroller. The relevant boards are <br\> 1. A100C01340, used in the TouchLine 70013, 703x3 and the interguard 707x stations <br\> 2. A100C01425, used in the TouchLine 7042, 7043 and many custom design flush mounted stations

Necessary equipment to preform the adjustment:

Oscilloscope with 10M ohm probe with insulating transformer on the power supply<br\>An AlphaCom or a TouchLine with display capabilities.<br\>A screwdriver suitable for the potmeter's RP1 and PR2. <br\><br\> Connect the oscilloscope probe to pin 11 on U5 (this is the PLL, the 74HCT4046), and the oscilloscope ground to the B-wire close to the station (not more than 3 meters). Set scope to 1Volt/line vertical division and 2 usec/line horisontal division. Adjust RP1 and RP2 until the waveform it is as shown on the figure, be accurate! Disconnect the board and reconnect after 2-3 seconds. Dial 789 (on a TouchLine, the AlphaCom will initialise automatically after a while but the 789 will work here as well). The display should now reset. <br\> <br\> This waveforms are very probe dependent. You have to experience the centre of the tolerance area yourself. Pay special attention to the slopes and the second peek on the curve.