Power Supply - Lexicon 960L Service Manual

960L Multi-Channel Digital Effects System Service Manual
quality of phaselock and proper operation of the audio systems in the 960L. If lock remains within tolerance
and no LKERRDET pulse occurs for 50 msec, U5 times out and the system is considered to be in lock.
During lock capture, U5 gets retriggered frequently, so PLL-LOCKED/ does not get asserted at all, and the
software can tell that the PLL is not locked. On-board LED D1 is driven directly from U5 to give a visible
indication of the UNLOCKED condition.
Default Operation
By default, the CPLD configures the PLL to lock internally to crystal U3, producing a 48kHz-sampling rate
when power is first applied to the card.

Power Supply

Power conditioning for the I/O Clock card involves local filtering and regulation of supplies from the
backplane.
Main 5VD from the backplane supplies the CPLD and other digital logic.
The 12V supplies from the backplane (+12VSUP/-12VSUP) are filtered by FB1/FB2 and associated
capacitors to supply +/-12V to the PLL active filter op-amp. +12VSUP also supplies the REMOTE
connectors through fuses as described previously.
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