Newest unident grant LT low AM power.

[Low_Boy]

It is not doing the best SSB power about 15 PEP. But AM is only doing 1W and swings backwards.
Final, driver and predriver are all good. The AM regulator 2SD1135 is showing over 7W in AM. Wrapped Torrid looks fine no broken wires. What am I missing?

 

[Robb]

7w dead key is waaaaay too high!

 

[ExitThirteen]

Sounds like it needs an alignment of the TX chain.


~Cheers~

 

[Low_Boy]

Robb put your glasses on lol. 1 watt Dk.
I went through the amp chain. I con go from 0 to 1 watt.

 

[loosecannon]

check VR10 itself.

this pot is one that gets turned a lot in some radios, and it could be worn out.
LC

 

[ExitThirteen]

In AM mode, check the voltage at the collector of the final, should be around 5V +/- 1V. If it's lower than that, I'd suspect a fault in the AM pass regulator circuit. Check that voltage and let us know how you get on.

~Cheers~

 

[Mudfoot]

7w dead key is waaaaay too high!

Robb put your glasses on lol. 1 watt Dk.
I went through the amp chain. I con go from 0 to 1 watt.

 

[loosecannon]

maybe he meant that he had 7 volts on the collector of the regulator, and that a 1 watt deadkey would be very weird to have at that voltage level.
LC

 

[Low_Boy]

Actually I do have 7.XX on the collector of the final and driver. I was wondering why something with that many volts showed so little power. I was thinking the same thing as you L.C. and changed VR10 way in the beginning of this project. I replaced the 2SD1135 regulator with one I had here. I do not remember where it came from. It was new and tested good on my tester. I can not find a good substitute that I have here to try in place of that D1135 but with that many volts to the final and driver I figure it should work.

 

[loosecannon]

ok, so you show 7 volts at the emitter of TR41? (closest leg to the front of the radio)

and that voltage varies with the position of VR10?
LC

 

[Low_Boy]

ok, so you show 7 volts at the emitter of TR41? (closest leg to the front of the radio)

and that voltage varies with the position of VR10?
LC

I will have to check this out also and post my findings.

 

[Low_Boy]

LC. I am now thinking The 2SD1135 TR41 must be a fake. 13V on the Emitter, and 13V on the collector and the base varies when turning VR10 from 2 to 7 volts?

EDIT. Just checked out another grant and this is correct. The base varies with VR10. This transistor is mounted to the back of the radio but if it was mounted to the side it would be the back leg that changes with VR10. emitter and collector on both radios have 13V

 

[711]

Check the bias transistor bro

 

[Low_Boy]

Check the bias transistor bro
View attachment 29089

Will do

 

[Low_Boy]

Thinking about this. I will test the bias diodes but I would have to say they are good because I was able to set driver and final bias with no problems.