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eHam Forums => Mods And Repairs => Topic started by: YONU on December 30, 2012, 04:22:45 PM



Title: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 30, 2012, 04:22:45 PM
hey all I need some advise on my YAESU FT-757GXII It receives and transmits fine on everything except LSB/USB according to a local ham the transmission sounds fine but what I hear is horribly distorted I am kind of at a loss so any advise/ideas would be good.

Thanks,
Reg
KK4NJC


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: KE3WD on December 30, 2012, 04:46:45 PM
Does the received distortion seem to get clearer when you turn the RF Gain down?

Do other modes such as AM show signs of distortion as well? 

If the answer to both is no, suspect alignment issues in the sideband scheme first. 

Alignment may go out for any number of reasons, from dirty calibration cap or trimmer to bad solder joints or components. 

73


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 30, 2012, 04:52:07 PM
no actually I have to have the RF gain up atleast halfway to hear anything even local Broadcast AM(normal?)  no the other modes sound good as I have been listening to a couple Foreign AM stations on it(better reception than my handheld shortwave)

Ok now the big question how do I check the Ca;ibration cap and trimmer?


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: KE3WD on December 30, 2012, 04:57:28 PM
You are talking about how far UP you have to turn the RF gain in order to hear something. 

I'm asking if turning it down while receiving the distorted ssb transmission has any effect on the distortion, such as alleviating the distortion somewhat, as that may be a useful clue as to which section of the radio to suspect. 


73


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 30, 2012, 04:59:12 PM
sorry no turning down had no affect


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: KE3WD on December 30, 2012, 04:59:59 PM
If you turn the Big Knob (tuning) can you make the distortion go away and get clear ssb reception? 


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 30, 2012, 06:02:33 PM
LOL nope turning the Big knob doesn't help it never clears up on LSB/USB


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: K7KBN on December 30, 2012, 07:57:03 PM
Try the clarifier function (see the manual).  You can't expect to tune a station in if your tuning control doesn't work.  Do you have it locked?


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 30, 2012, 07:59:20 PM
ok now I have to sound extra stupid what do you mean when you say locked? and I will give the clarifier control a shot tomorrow


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: KA4POL on December 30, 2012, 11:31:36 PM
If you push the 'Lock' button you can no longer tune to a station. The same applies if you are using a memory channel. You would see this already in your frequency display.

Getting to your question, could you tell us how it all started. Did your rig work fine and then the problem came up? It would be very helpful to know that for analyzing what is behind your observation.


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 31, 2012, 06:36:28 AM
Nope lock is not on.

The problem came up as far as I can tell from the time I turned the radio on as I pickedup the radio in august but then dent take my exam until December so like I said it was doing this from day one.


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: K8AXW on December 31, 2012, 07:58:20 AM
YONO:  Do you have the switch on a narrow filter?


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on December 31, 2012, 08:08:13 AM
Well I went through the manual the only reference to a filter I can find is the cw-n and cw-w on the mode switch is this what you are referring to


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: K7KBN on January 01, 2013, 05:23:31 PM
Page 7 of the manual covers the clarifier....


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: K8AXW on January 01, 2013, 07:58:05 PM
YONO:  Not familiar with your radio but it should have CW and SSB positions on the switch.  The CW positions are narrow for copying CW and of course the SSB is for SSB voice.  If you have a CW-N (Narrow) and a CW-W (Wide) then I have to ask are you trying to listen to SSB while the switch is in the CW-W position?

Make sure the switch is in the SSB position.



Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on January 01, 2013, 08:09:21 PM
Nope not trying to listen on cw I did try it just to see it it would work but I know that won't work


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on January 09, 2013, 05:59:59 PM
hey all I have it working it was the POT for the shift knob  I do have a curiosity question when I have the mic keyed the Freq will start going up as if turning the knob I have checked the mic controls for shorts but I have yet to find anything any ideas.

Thanks,
Reg
KK4NJC


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: KA4POL on January 09, 2013, 10:19:52 PM
Which mic do you use? It is most likely the contacts for the UP function are closed. This would be pins 1 and 2 of the plug if it is the MH-1. Check it with an Ohm-meter.


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on January 09, 2013, 10:25:48 PM
I have the mic with the up down controls and I suspected this so I detached them inside the mic and insulated each wire however it still happens but now that I think of it not ans frequently I will check the mic connector end for a short (sometimes it takes thinking about what you have done to figure it out LOL)

Thanks,
Reg


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: KA4POL on January 09, 2013, 11:40:56 PM
If you pull the plug it should not occur. Else it is inside the rig. What according to Mr. Murphy also could happen is damaged insulation between wires by some abnormal kink of the cable.
Having a problem I use to sleep one night over it. In the morning it is either gone or I have an ides how to solve it.


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on January 10, 2013, 12:24:45 AM
You are right actually I thought about it and when the mic is unhooked and I use the mix switch it doesn't do it that was what made me initially try unlookibg the buttons


Title: RE: YAESU FT-757GXII LSB/USB help
Post by: YONU on January 10, 2013, 08:29:43 PM
well I sort of sorted it out and solved the problem I opened up the mic connector on the cable and removed the wirs for the mic controls works great now and since I currently don't use the scan controls I don't even notice anything is gone

Thanks,
Reg
KK4NJC