Discussion in 'Radio Circuits, Repair & Performance' started by N1EBC, Oct 10, 2021.
How much RF are you seeing on the output of the final?
Looks like about 11v rms.
I traced out the signal path, and it goes through some relays after the power amplifier. If the unit is drawing a few amps of current, it is likely that things are good up to the power amp (but not certain). You could have a relay problem or something else going on. The fact that it works on other bands indicates that the final is working, but probably something else in the path.
Command failure is the relay.
Before Ijust replace the relay. I check for signal before and after the relay. An verify voltage at the relay then report back.
Thanks for the help
So i get signal at l1105 but no signal at l1107 so it looks like rL1002 is stuck.
I can't seem to find d1113 or d117 to check the voltage on the relay.
g5a-237p relays I cannot seem to find a replacement anyone have an alternative?
Check to make sure the voltage on the relay coil is actually switching. I think that relay selects UHF or 2M, so switch between those bands while watching the coil voltage on pin 8 of the relay switch from 12v to close to zero volts.
Sooooo i don't think I can access that pin unless I pull the board and flip it over . How is tat going to be on the final with no actual heatsink?
If you have an alternative way to check it I'm all ears.
Can you get to the 22 Ohm resistor that is in series with the relay coil ?
That would be a negative as they are on the bottom side of the board.