Re: Ft-301ad blinking s-meter no transmit
开云体育The LPF unit is the transmitter low pass network but also contains the VSWR detector and the trip control for the Protector. If high SWR or a fault in the detector circuit itself, the Protector will activate. That relay is not a pass-through but must be closed in order for the transmitter section to work properly.? Look at the wiper of the potentiometer that supplies drive to the thyristor gate. Is there any DC voltage present? 73 - Fred, N8YX? -------- Original message -------- From: KI7WQH Steve <sdandrus@...> Date: 5/6/20 10:38 PM (GMT-05:00) To: Fred_N8YX <N8YX@...>, [email protected] Subject: Re: [yaesuft301d] Ft-301ad blinking s-meter no transmit I think I'm misunderstanding something. From what I can see on the block diagram, the LPF unit is like a gateway between the PA and then antenna. The relay on the LPF unit needs to be closed in order to transmit. For some reason on this radio the relay is open, which is the root of the problem. I thought by bypassing the relay and just jumping K1 to K2 it would essentially take the LPF unit out of the mix and the radio would transmit. This doesn't seem to be the case. So I think I'm misunderstanding what the LPF and blanking units do. |