TrC457 (upd858) ssb power....

[Pirate71]

Hi guys, i have 18 watts on my 457 ssb and i want to lowering it. CT7 is not fonctionnal change anything. Mods is not made on d21 and d22.....any idea??? Thks a lot!!

 

[Unit 75]

Check out FET5 .22v tx ssb on the gate. The source is grounded and 1.01v tx ssb on the drain. Check D46. Also check CT7 and make sure it is not damaged and is functional.

 

[Mk121]

Check c155 its a very small 1pf cap. It may be cut or missing.

 

[nomadradio]

Make sure that FET5 and TR42 are both there. The sideband limiter in this radio is NOT connected to the mike circuits in any way. When the ALC trimmer cap CT7 goes bad, you usually get the opposite problem. Reduced sideband power.

Somebody has unhooked something in the ALC circuit, looking for a bigger wattmeter reading would be my best guess.

A tiny solder short across the foil pads of CT7 would do this.

73

 

[ExitThirteen]

Also make sure that TR16 has not been removed or modified in any way. Check R72 as well, make sure that hasn't been changed. It can vary from 220 ohms to 470 ohms from factory, but some people remove it and put in something very low resistance, or install a jumper.


~Cheers~