Hello,
I hope I can shed a little light on this.
It is possible your TX troubles are caused by a bad Capacitor.
There are a couple in the radio that are low rated.
10v instead of 16v or 35v capacitors. They can go from slight pwr surges or from 'Old Age' because they are in circuits that run at very near to 10v. (typical Tolerances suggest these should be rated 2x to 3x the operating voltage)
So much for the WHY..
I suggest you check or replace C75 - 10v 220uf cap with a 16v or 35v 220uf cap. This cap is on the supply line of IC104 which in part is the TX Control IC.
See the 'New' IC Voltage Charts on my site for more info.
( Rogerbird.tripod.com/ )
Ic Voltage chart
See the voltage at Pin 1 of IC104 (TX 7.6v, RX 7.2v ) , Pin 8 is the TX Control pin feeding Q136,
E C B
Q136 Tx 0.0 0.0 0.7                                                                        
Rx         0.0 8.0 0.0
then Q125 (TX 8v Switch )
E C B
Q125         Tx 7.3 7.8 8.0                                                                                
Rx 7.4 0.0 8.0
My 'guess' is that C75 is shorted and not providing voltage to the input of IC104.
For a great board layout of the Lincoln/hr2510 go to:
Cbtricks HR2510
I hope this helps..
Roger
</p>
I hope I can shed a little light on this.
It is possible your TX troubles are caused by a bad Capacitor.
There are a couple in the radio that are low rated.
10v instead of 16v or 35v capacitors. They can go from slight pwr surges or from 'Old Age' because they are in circuits that run at very near to 10v. (typical Tolerances suggest these should be rated 2x to 3x the operating voltage)
So much for the WHY..
I suggest you check or replace C75 - 10v 220uf cap with a 16v or 35v 220uf cap. This cap is on the supply line of IC104 which in part is the TX Control IC.
See the 'New' IC Voltage Charts on my site for more info.
( Rogerbird.tripod.com/ )
Ic Voltage chart
See the voltage at Pin 1 of IC104 (TX 7.6v, RX 7.2v ) , Pin 8 is the TX Control pin feeding Q136,
E C B
Q136 Tx 0.0 0.0 0.7                                                                        
Rx         0.0 8.0 0.0
then Q125 (TX 8v Switch )
E C B
Q125         Tx 7.3 7.8 8.0                                                                                
Rx 7.4 0.0 8.0
My 'guess' is that C75 is shorted and not providing voltage to the input of IC104.
For a great board layout of the Lincoln/hr2510 go to:
Cbtricks HR2510
I hope this helps..
Roger
</p>
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