The AM Forum

Hello: Again My FR 101 S receiver will not mute, push standby button it mutes open mute phono plug on rear panel it mutes half way no complete shut off, I have completely went through the circuit found nothing. I do not have a spare Q1 to try, can someone tell me how this circuit works, or agree to fix it I will ship and pay.

John W9BFOw

Hello: Dose anyone have a Q1 transistor like the one in the MUTE circuit of the FR101s yaesu receiver ?

John W9BFO

Why don't you identify what the transistor is? Not everyone wants to run around the Internet to find a schematic for this receiver.

Hello: I am sorry I should have done that there is more than 1 Q1's in that radio. (2SC735Y) is the number on the schematic, I am sure this can be crossed to another transistor, but I dont't have a book for that.

John W9BFO

One internet reference says an NTE289A is "the equivalent replacement".

John,

I’m not quite clear on all the details. Are you saying it mutes completely when you depress the standby switch but only partially mutes when you pull the mute line low? Q1 pulls the AGC line to low when you pull the mute line low but the Monitor variable resistor keeps the AGC line partially above ground, allowing “monitoring” of the transmit signal. The standby switch pulls the AGC line completely low with a mechanical switch. It does not allow for monitoring.

Have you tried adjusting the Monitor control?

Hello: When the mute is opened (the gnd is removed) the radio dose not mute completely, the S meter drops back to about 1/2 to half of what it was reading. I can hear the tnx audio in the speaker. I think it is the 2SC735Y transistor but I don't have one to replace it with. Thanks for all you guys help I will try to find one, and yes the monitor knob is turned completly counter clock wise.

John W9BFO