• 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.

TrC457 (upd858) ssb power....

Pirate71

Member
Aug 12, 2015
11
0
11
53
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!!
 

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.
 
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
 
  • Like
Reactions: Unit 75
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~
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.
  • dxBot:
    kennyjames 0151 has left the room.