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OK,
Had this radio come in a few weeks ago. It had a recieve problem. Signals would fade down but the hash (static) levels and s-meter would stay the same. Got that fixed. It has now came back with a TX problem.

Set radio to channel 20.
If you switch so ssb mode and key mic, I have a 10 watt carrier. If you modulate that it will swing to 11 watts.shows a frequency of 26.937mhz.
Switch to am.
Dead key is 2 watts and modulates to 10 watts.
Frequency 27.205 mhz.

So on ssb it is oscillating.

Voltage checks on driver and final in AM mode

--------B-----------C------------E
TR44
RX-----0.0--------5.56---------0.0
TX----1.16--------5.15---------0.03

TR43
RX-----0.00-------5.56---------0.00
TX-----0.53-------5.7----------0.03

Voltage checks on driver and final in SSB mode

--------B-----------C------------E

TR44
RX----0.0---------13.8----------0.0
TX----0.32--------11.71--------0.05

TR43
RX-----0.00------13.81----------0.00
TX-----0.59-------0.0-----------0.05

I have been using the DX-11 and DX 77 schematic to go through this radio.
In ssb you will notice that there is 0 volts in TX mode TR43 ? Dont think that is right.
According to voltage charts it should be 0.00 in RX and 13.0 in TX on collector.

I am about to pull my hair out with this beast.

Any ideas?

Did you check the alignment of the PLL? Offsets and such? Key on SSB sounds like it is out of kilter.

BC

__________________
BC

Oh yea, Did a complete alignment check on it.

Guess you asked that because of ssb frequency being off? If so I think that is because of the final is going into oscillating.

But the osc and ref freqs are stable when this is going on?

__________________
BC

Solid as a rock.
Trying to hunt down where my 13 volts is at on TX.

Heres a thought for ya.
I replaced IC4 when I was working on the RX section a while back. I just replaced it again and the radio worked fine. No carrier on ssb. Tried 3 times and was fine. The fourth time I keyed the mic, there was a carrier.
So I am off now to find voltage checkes for IC 4. Maybe there is something there that is taking out part of it.