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Old 11th Jul 2018, 11:22 pm   #16
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Info. on 'phone requested

Quote:
Originally Posted by Herald1360 View Post
Could the twisted pair lines be transposed giving wrong polarity dc? .
Quote:
Originally Posted by russell_w_b View Post
Pretty sure there'll be a bridge-rectifier across the line feeding the ancillary circuits, given that line polarity can change arbitrarily or determined by switching sequences, without ill-effect.
I did open the 'phone up, early in my investigations. I did see four diodes on the pcb that were located near to where the incoming line meets that pcb.

Al.
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