Galaxy DX-2547 low SSB output, help?

[Adamf]

In which mode AM/FM or SSB?

Remember in post #4 - two different "modes" - one steady state (carrier like AM or FM) then in SSB - the differences in the heating of the parts between both modes gives us the clues.

And since you're in MOSFET one, the biasing is different in the FINAL and DRIVER area - so let's profile the Pre-Drivers (52 and 51 first) to remove any doubt - then work on the input side of the Driver and Finals.

Hi Andy, I should have said, I did it modulating in SSB at full output. Adam

 

[Adamf]

Hi Andy, I should have said that, tested in USB with modulation to full output. Adam

 

[Handy Andy]

The repeat the test - in Carrier (AM or FM) and measure temperature

Be sure to include 51 and 52 in your measurements

Then if Final is still too hot (or higher temperature then any of the others) you may have a turn on biasing problem - and just need to re-adjust bias for Finals - not by voltage - but by current

 

[Adamf]

The repeat the test - in Carrier (AM or FM) and measure temperature

Be sure to include 51 and 52 in your measurements

Then if Final is still too hot (or higher temperature then any of the others) you may have a turn on biasing problem - and just need to re-adjust bias for Finals - not by voltage - but by current

Hi Andy, when I originally had this problem a while ago I had tried to adjust the bias (using the manual etc) but could not get the voltages up high enough according to the specs, they were too low. Does that tell you anything? Adam

 

[loosecannon]

just throwing this out there, but your mic gain is at max right?
LC

 

[Handy Andy]

Then, by your word of MOSFET based - you should study this schematic and see what and why you can't get "voltages" right.

Again, DO NOT set by voltage - you SET BY CURRENT.

If you don't then I cannot help you any further...