BobE

Yes, all wiring is fine.

The Scantronic Sounder External Wired Backplate, SDR-WEXT-G2, installed a few years ago worked perfectly until about a week ago, when I noticed that the 'comfort LEDs' had stopped working. On further investigation the unt does not sound the siren when an alarm condition is triggered, although the internal Scantronic 9651PD does. On opening the external sounder box its cover tamper switch does not trigger the external siren but again it does trigger the 9651PD. On further investigation, the internal battery of the external sounder is fully charged, therefore I suspect the sounder circuit board is faulty. Are replacement circuit boards available for this unit as I don't want to have to replace the whole external sounder box?

Many thanks for your confirmation. I can now go ahead with confidence.

And the Bosch Blue Line Gen2 Passive-infrared Detector is: Model: ISC-BPR2-W12 I hope that clarifies both the Bosch and Scantronic models

Which model? Its a Scantronic 9651PD-41 Grade 2 8 zone panel.