Galaxy DX959 no audio out of the speaker in SSB mode

[RedDeadEd]

Hello

Model radio Galaxy DX959

My issue is in SSB mode only everything ells is working fine. The damage occurred wail following the transmitter alignment instructions from the manufacture step 5 for the BIAS Current.


BIAS Current:
Set radio to CH 20
USB TX mode.
MOD off.
Connect current meter to TP7(+) and TP9(-) 50 mA VR12

Connect current meter to TP7(+) and TP8(-) 100 mA VR10

As you can see the first step is to connect a AMP meter to TP 7 and TP 9... Well do to the orientation of the radio I accordantly mistaken TP9 for TP6. Now I have absolutely no audio out of the speaker in SSB mode, the S meter needle still moves when others are keying but even with the volume turned all the way up still nothing comes through the speaker. Any suggestions or help anyone can give is greatly appreciated.

Thank you

 

[Se7en]

are you talking about talkback? or are you saying no one on SSB can hear you?

 

[sp5it]

Where TP6 is located?

 

[Robb]

Where TP6 is located?

Galaxy Radios DX959 Service Manual

 

[sp5it]

I have schematic Robb, just couldn't find it.
Anyway: D36, D35, D13, D95, D96, D53, D85, Q24, Q16 to check.

 

[RedDeadEd]

I can transmit and be heard the talk back still works. I just cant hear others. In AM mode I can hear fine checking the out put of IC8 with a Oscilloscope in SSB mode there is nothing there but in AM mode there is a signal. I have checked what I can see from the schematic as directly related... But I don't fully understand the circuit I know the input signal from the antenna gets demodulated and separated amplified and should be present at the out put of IC8... but its not and I don't know how the circuit is treating the SSB signal compared to the AM... what makes it different?

Maybe if someone had a block diagram showing each section in relation to component and AM goes this way and SSB goes that way.

 

[RedDeadEd]

I also have been mainly focusing on the squelch circuit because that is how the radio is acting. like the squelch is up all the way

 

[RedDeadEd]

I know what I did I put 12 volts on test point 6.. just for a millisecond till the current blow the fuse in the meter I just truly cant find what got damaged because of it.

 

[sp5it]

Did you already checked parts what I told ya?
MIke

 

[RedDeadEd]

I dont have a record of what exactly I checked so fare; I won’t to say yes but… I will do a check of what you have listed to be safe.

 

[RedDeadEd]

Man I can’t believe it… It was D36 could have sworn I checked that I mean it’s the diode closest to the test point. I have been doing this to long to make that mistake. Sorry if I wasted your time.
Diode is replaced and SSB is working again.
Thank you for your time and thank you for asking me to measure those components.

 

[Robb]

I'm glad you got it fixed.

 

[RedDeadEd]

Thanks… The simple mistakes are always the essayist to make.