Sorry to bring this back up the pull up resistor did not start the COR. Looking at the schematic the MMBT3904 NPN is connected to pin 8 from this a 10k resistor takes it to the MC68xxx processor. Best guess ? programming? or NPN transistor.
Thanks, Henry --- In Repeater-Builder@yahoogroups.com, "Henry Harms" <[EMAIL PROTECTED]> wrote: > > OK! thanks Russ, that makes perfect sense. I will try that this evening. > > 73's Henry > > > --- In Repeater-Builder@yahoogroups.com, "Russ Crisp" <crisp@> wrote: > > > > Hello Henry. > > > > > > > > I believe the COS on the GM300 is active LO. Open collector.. Try using > > something like a 10K pull up resistor tied back to 12v. Then, when the > > receiver hears a signal, the voltage at the junction of the 10K and pin > > 8 should go from 12v to near 0. Set the ICS controller to use active LO > > COR. > > > > > > > > Hope I'm reading you right here. > > > > > > > > 73's > > > > Russ > > > > K4RCC > > > > > > > > From: Repeater-Builder@yahoogroups.com > > [mailto:[EMAIL PROTECTED] On Behalf Of Henry Harms > > Sent: Saturday, January 26, 2008 4:18 PM > > To: Repeater-Builder@yahoogroups.com > > Subject: [Repeater-Builder] COR on GM300 8 channel reciever > > > > > > > > I have inherited a GR300 UHF repeater reprogrammed to 440 ham bands, > > and I am trying to set up a ICS Basic controller. The RIC box was hit > > by lightening and blew four of the IC's into little pieces. The radios > > seem to be working fine. They receive and transmit as expected but, I > > don't seem to have COR on pin 8. Voltage stays at 0 either way. This > > is my first attempt at building a repeater. Can't seem to find > > anything in the service or operators manual as to how much voltage > > should be present on pin eight and I am guessing that it is broke, I > > hope not as a ham in Missouri we could use a UHF machine linked to the > > Interlink for emergency use. Any help would be appreciated. Thanks in > > advance. > > > > KB0ROX Henry > > >
