Yaesu FT-7 - UK Vintage Radio Repair and Restoration Discussion Forum

tin-tin · 3rd Aug 2011, 4:44 pm

Hi,

I came to use my Yaesu FT7 after a few months of not using it. When I key the mic on SSB I get a carrier of tone, but when I speak into the mic no modulation at all but it is transmiting. On CW it is transmitting OK.

terrybull · 3rd Aug 2011, 5:07 pm

Check the mike is working. Have you got a spare to try? The jack not tarnished etc

MichaelR · 3rd Aug 2011, 6:01 pm

I would check that the mode switch is changing to SSB. It is behaving as though you are still in cw mode.

Mike

tin-tin · 5th Aug 2011, 6:21 pm

I have tryed a diffent mike and it was still the same and it is changing to ssb from cw.

Dave

MichaelR · 5th Aug 2011, 6:43 pm

How do you know it is changing to ssb on transmit.

Is it behaving as it should with the drive and mic gain controls.

Does it work ok in AM mode on transmit

Mike

tin-tin · 11th Aug 2011, 6:47 pm

The radio does not have AM mode on it and no drive control on it.
The mic gain control was working before this tone started but you can not hear any modulation to test the mic gain.
It changing to ssb when you listen on the bands.

david

MichaelR · 11th Aug 2011, 10:07 pm

Ok so you have not got the later B version you have the low power first release unit.

Have you got a manual because if it is nothing obvious then it means starting to debug the circuit.

Mike

niteviser · 21st Aug 2011, 10:53 pm

If I recall from the many years ago when I had an FT-7, the first fault finding procedure was to re-seat all the PCB's, especially after any period of non-use. If you can identify the boards associated with TX Audio etc, start with them first. I shudder when I remember seeing the '7' with soldered edge connectors instead of the original PCB surface, which only exacerbated the problem.

n

tin-tin · 23rd Aug 2011, 7:15 pm

I got a manual off the net but not a very good copy of it.
I tryed the radio the other day i was not geting the tone there,but aload rushing noise and very bad cracking noise.But very low modulation with mikegain turned up full with any mike pluged in.
So the PCB's in the radio are push in boards so do the soldered edge connectors need clearing or not ?
But what do you clear them with?
How do you no which board is which as manual does not tell you .

david

thx1138 · 30th Aug 2011, 5:10 pm

Hi,I have had both the FT7 and later FT7B. Kill power, just remove lid, pull each pcb out slowly use ipa alcohol on a cotton bud,clean and resit. Basically do it for all the boards you can lift out.

Theres one down the front on left from memory that tended to throw up problems with tx and audio. Basically its an old radio and anything can happen with this modular assembly. Reminds me to pull my one from the box and fire it up. The NB is awful btw,almost useless. Anyway best of luck.

3rd Aug 2011, 4:44 pm	#1
tin-tin Retired Dormant Member Join Date: Apr 2011 Location: Birmingham Posts: 16	Yaesu FT-7 Hi, I came to use my Yaesu FT7 after a few months of not using it. When I key the mic on SSB I get a carrier of tone, but when I speak into the mic no modulation at all but it is transmiting. On CW it is transmitting OK.

3rd Aug 2011, 5:07 pm	#2
terrybull Octode Join Date: Jan 2011 Location: Southwell, Nottinghamshire, UK. Posts: 1,781	Re: Yaesu FT-7 Check the mike is working. Have you got a spare to try? The jack not tarnished etc

3rd Aug 2011, 6:01 pm	#3
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Yaesu FT-7 I would check that the mode switch is changing to SSB. It is behaving as though you are still in cw mode. Mike

5th Aug 2011, 6:21 pm	#4
tin-tin Retired Dormant Member Join Date: Apr 2011 Location: Birmingham Posts: 16	Re: Yaesu FT-7 I have tryed a diffent mike and it was still the same and it is changing to ssb from cw. Dave

5th Aug 2011, 6:43 pm	#5
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Yaesu FT-7 How do you know it is changing to ssb on transmit. Is it behaving as it should with the drive and mic gain controls. Does it work ok in AM mode on transmit Mike

11th Aug 2011, 6:47 pm	#6
tin-tin Retired Dormant Member Join Date: Apr 2011 Location: Birmingham Posts: 16	Re: Yaesu FT-7 The radio does not have AM mode on it and no drive control on it. The mic gain control was working before this tone started but you can not hear any modulation to test the mic gain. It changing to ssb when you listen on the bands. david

11th Aug 2011, 10:07 pm	#7
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Yaesu FT-7 Ok so you have not got the later B version you have the low power first release unit. Have you got a manual because if it is nothing obvious then it means starting to debug the circuit. Mike

21st Aug 2011, 10:53 pm	#8
niteviser Diode Join Date: May 2011 Location: Brisbane, Australia Posts: 8	Re: Yaesu FT-7 If I recall from the many years ago when I had an FT-7, the first fault finding procedure was to re-seat all the PCB's, especially after any period of non-use. If you can identify the boards associated with TX Audio etc, start with them first. I shudder when I remember seeing the '7' with soldered edge connectors instead of the original PCB surface, which only exacerbated the problem. n

23rd Aug 2011, 7:15 pm	#9
tin-tin Retired Dormant Member Join Date: Apr 2011 Location: Birmingham Posts: 16	Re: Yaesu FT-7 I got a manual off the net but not a very good copy of it. I tryed the radio the other day i was not geting the tone there,but aload rushing noise and very bad cracking noise.But very low modulation with mikegain turned up full with any mike pluged in. So the PCB's in the radio are push in boards so do the soldered edge connectors need clearing or not ? But what do you clear them with? How do you no which board is which as manual does not tell you . david

30th Aug 2011, 5:10 pm	#10
thx1138 Tetrode Join Date: May 2007 Location: Bratislava, Slovakia Posts: 65	Re: Yaesu FT-7 Hi,I have had both the FT7 and later FT7B. Kill power, just remove lid, pull each pcb out slowly use ipa alcohol on a cotton bud,clean and resit. Basically do it for all the boards you can lift out. Theres one down the front on left from memory that tended to throw up problems with tx and audio. Basically its an old radio and anything can happen with this modular assembly. Reminds me to pull my one from the box and fire it up. The NB is awful btw,almost useless. Anyway best of luck.