3/6/08 888-2463-001 4-13
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
Diamond Series™
Equalization Reset and Hold is normally activated from the Main Controller. When the
Main Controller fails, the Equalization Reset and Hold will be activated on the off-air
Exciter only. JP1 selects between Reset and Hold.
4.6.2.6 U10 CPLD
The main function of the Life Support board is contained in the CPLD (complex
programmable logic device) U10. It receives downloads via the In-System
Programming (ISP) through J7, 21-24. The JTAG inputs are for factory in-system
programmability and for field service updates to the CLPD.
In dual Exciter transmitters, the Auto Exciter changer over (Auto Switch) is enabled by
connectiing JP5.
While adjusting VSWR, JP3 can be set to 2-3, allowing the VSWR indication to surpass
the threshold without counting it in the 3 strike counter. Under normal operation, when
the transmitter has failed the 3-strike, the VSWR fault will mute the Exciter.
4.6.2.7 Exciter/Driver selector
For dual Exciter/Driver transmitters, S1 and S2 are used to switch the Drive chain
manually. These switches are enabled only when in the Life Support mode, when the
Main Controller has failed.
4.6.2.8 Drive Switch Interface
When dual Exciter/Drivers are used, J3-23 will be active LOW. J3-21 and J3-22 come
from the drive switch to monitor the status (position) of the switch.
4.6.2.9 ON/OFF Command pulse stretchers
One-shot U30 serves as a pulse stretcher when the system is turned ON and OFF. The
On Pulse Command from the CPLD is stretched to a 100ms pulse to the PA cabinet(s).
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