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Question on Saber connector pin function
Posted: Thu May 20, 2004 7:55 pm
by hycheng
Hi there,
What is the use of pin 8 Opt B+ in the Saber connector ?
It is not used in most of the headset/handmic I have but on one the headset it is used but it starts to give me strange behavior (will not disconnect after keyed).
Thanks in advanced,
Chris
Posted: Fri May 21, 2004 9:27 pm
by N4UMJ
I believe this "pin 8 Opt B+" is for powering up active circuitry necessary to activate the VOX feature. I know it is utilized by the SVA (for radio voltage monitoring) too when connected to one.
On a related Saber stuck PTT topic there was a service bulletin about the RTK4203 Program Test Cable and the radio remaining keyed after dekeying(on VHF). The Motorola fix was to put a 390pf capacitor across the voltage reference device (ZENER.) This acted to shunt some of the unintentional RF voltage across the Zener to ground. (Mine has a 500pf)
The connect points would be from the "Option Select" (Pin 7-Universal Connector) to Gnd (Pin 14 - Universal connector coax ground/shield)
Maybe give that a shot.....
Good Luck!
Eddie
Posted: Sun May 23, 2004 8:02 am
by mike m
It is the main bias pin for setting up the feature of the OPTion SELect pin, it is connected off of the main B+ line of the radios supply I.E. the battery directly after the ON/OFF switch.
Its main purpose is to supply the voltage to bias up the Option select pin depending on what config of Zener diodes is used in the external device.
The OPT select pin is then used to select things like external spkr mic, external antenna, XTVA, test cable, resetting the radio so you can do a re-program after a royal crash etc.
Mike