-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Cobra 29 LTD Classic FL2 Filter
- Thread starter RCIGuy
- Start date
It's waiting for input - the AC (RF Signal) that makes it conduct.
But Base needs power...
So if TX is on, yet Pin 15 D14 line is "Dead" the thing is either out of lock, or there is a missing signal - the other half - either 10.240 or the 16~17MHz - you seem to have RX so the conversion is working - but no TX voltage - did you look for, observe operation of and check TR21? The Keying Transistor? It's a 2SA733 - PNP.
It should work - else you would not get a RED TX LED light - so you're missing the other half or you have other issues - Since it is not getting Bias - either the D14/TX Mixer is not working or it's not able to work because it's not seeing a signal (or enough of both) to fire up and produce power to D14 to rectify thru C109 from that twin tank L21.
But Base needs power...
So if TX is on, yet Pin 15 D14 line is "Dead" the thing is either out of lock, or there is a missing signal - the other half - either 10.240 or the 16~17MHz - you seem to have RX so the conversion is working - but no TX voltage - did you look for, observe operation of and check TR21? The Keying Transistor? It's a 2SA733 - PNP.
It should work - else you would not get a RED TX LED light - so you're missing the other half or you have other issues - Since it is not getting Bias - either the D14/TX Mixer is not working or it's not able to work because it's not seeing a signal (or enough of both) to fire up and produce power to D14 to rectify thru C109 from that twin tank L21.
Replaced TR21 a few days ago, havent made any progress with it, I appreciate all the help from everyone but its lookin like the repair is not gonna happen. Ive done all i can think of with my limited diagnostic skills, every time i turn it on to check something another problem shows itself, it has fought me the whole way. Very frustrated.
Ok i thought id give it one more go, turned it on and now channel display is not working, the green rx light only on when "dim" function is on, when switched to bright it loses rx light and no rx is heard, the best part is the right side (side of radio case) of C104 gets so hot you can smell it and it will burn your finger.
Shorted TR22-TR23? Now C104 bad? I dont have the parts to change them out, and i dont dare to turn it on again, not sure where to go with it at this point.
Shorted TR22-TR23? Now C104 bad? I dont have the parts to change them out, and i dont dare to turn it on again, not sure where to go with it at this point.