422TTL modification for Bench DC Power

Written By: warrenjrose
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422TTL modification for Bench DC Power

Difficulty

Moderate

Steps

3

Time Required

30 minutes

Introduction

The Advantech 422TTL is used to convert a TTL signal, into a differential 422 signal. However, when using the recommended power supply, the output on the RS-422 side is absolute garbage due to the cheap switching power supply injecting noise. We were converting PPS.

We fixed this by using a bench top 12VDC power supply for nice clean power. This guide will document that modification.

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    • Remove side sticker (DC Power 12VDC)

    • Remove hardware (Screws and metal tabs)

    • Carefully lift 4 tabs (2 per side) to split unit into two halves.

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    • Remove the PCB from housing, examining where the headphone style power adapter attaches.

    • Desolder and remove the power adapter.

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    • Positive (red) and negative (black) power lines should attach where the socket was removed.

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

warrenjrose

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