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Author Topic: Icom 207H Can Hear Great, Can't talk...  (Read 2864 times)
KD5TGN
Member

Posts: 36




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« on: April 23, 2010, 05:14:43 PM »

Greetings all,
I have an Icom 207H that was given to me. I can hear great, but it doesn't seem to be talking. I've tried to hit the local repeaters and nothing. It shows it's transmitting at the correct power (5, 10, 20, 50 watts) but nothing either on the repeaters (PL tone and offsets are correct) or simplex. I am running through a 5/8th wave mag mount and all the connections appear to be good. I don't have another rig to test it against.  Any thoughts?

Cheers,
Dan
KD5TGN
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N6NKN
Member

Posts: 425




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« Reply #1 on: April 23, 2010, 06:11:12 PM »

What do you see on your external wattmeter?

You do have an external wattmeter. Right? Grin
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KD5TGN
Member

Posts: 36




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« Reply #2 on: April 23, 2010, 07:51:44 PM »

hmmm watt meter? Wink

No, just have the trusty ole DVM....
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AD6KA
Member

Posts: 2232




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« Reply #3 on: April 23, 2010, 10:57:25 PM »

Ideal way to test the output is with an external
VHF wattmeter into a 50 ohm dummy load.
Even an HF meter would help a little bit.

Have you tried a partial or full reset of the radio?
Do you have an HT or even a scanner that you can listen
for your signal on? Does a friend have either one?

What does the guy who gave it to you say?
Did he tell you it had problems? Have you called
him up and told him you're having problems?

You said you have a 5/8 wave mobile mount. Have to
ask this; is it on a car or other large ground plane?
(I've head about people buying mag mount antennas and setting
them on the desk next to the rig, or on a wooden patio railing).
Have you used this exact antenna before for transmitting,
*or did it come with the radio, also untested*?

Have you used an IC-207H before? If not, do you have
the manual? Rigs differ, and sometimes in odd ways.
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WB6BYU
Member

Posts: 13017




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« Reply #4 on: April 24, 2010, 06:56:12 AM »

Try working a local ham on simplex, or a VERY local repeater.  Many of the mobile rigs
will put out a very low signal - perhaps 10mW or less - when the final amplifier module
goes bad.  This isn't uncommon if the rig is used at high power a lot without good
ventilation to keep it cool.  (I have a 207 on the bench for just that problem.)

Also try a 440 repeater and see if that works better: the 207 uses two separate
amplifier modules, and it is likely that the 440 side is still working if that is the problem.
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KD5TGN
Member

Posts: 36




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« Reply #5 on: April 24, 2010, 07:14:34 AM »


Have you tried a partial or full reset of the radio?
Do you have an HT or even a scanner that you can listen
for your signal on? Does a friend have either one?
Yes, both full and partial per the Icom Manual
No, this is the only radio I have at the moment
All my Ham friends live out of state, ack.

What does the guy who gave it to you say?
Did he tell you it had problems? Have you called
him up and told him you're having problems?
It was found in a desk where I used to work. There had been a ham working there a couple of years ago but they were unable to locate him, so I got the radio.

You said you have a 5/8 wave mobile mount. Have to
ask this; is it on a car or other large ground plane?
(I've head about people buying mag mount antennas and setting
them on the desk next to the rig, or on a wooden patio railing).
Have you used this exact antenna before for transmitting,
*or did it come with the radio, also untested*?
Antenna is center mounted on a Ford Van. This is the same antenna that I used with my old 207.

Have you used an IC-207H before? If not, do you have
the manual? Rigs differ, and sometimes in odd ways.
I owned a 207 for a couple of years and I have the manual.  I've been going through it step by step and everything appears as it should.


[/quote]
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KD5TGN
Member

Posts: 36




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« Reply #6 on: April 24, 2010, 07:17:28 AM »

Try working a local ham on simplex, or a VERY local repeater.  Many of the mobile rigs
will put out a very low signal - perhaps 10mW or less - when the final amplifier module
goes bad.  This isn't uncommon if the rig is used at high power a lot without good
ventilation to keep it cool.  (I have a 207 on the bench for just that problem.)

Also try a 440 repeater and see if that works better: the 207 uses two separate
amplifier modules, and it is likely that the 440 side is still working if that is the problem.
I attempted this yesterday. The W5PAA repeater is about 3 miles from me, and I can't hit it.
I also attempted 440 with the same result, but I have never had success with 440 from here, so that's inconclusive.
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KZ1X
Member

Posts: 3227




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« Reply #7 on: April 24, 2010, 07:20:04 AM »

If memory serves, the panel indicator for TX power on that radio is not actually showing you that there's RF.  It's driven from the MCU.

Since all you have is a DVM, what you want to do is measure the voltage drop across the fuse when you transmit.  If you don't see much of a drop, the radio isn't drawing any current on TX ... which may mean the output module for that band is dead.
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KE3WD
Member

Posts: 5694




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« Reply #8 on: April 24, 2010, 07:57:57 AM »

A low voltage filament lamp placed across the antenna connector is a fast way to see if there is any output in xmit mode or not. 

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KE7RTV
Member

Posts: 35




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« Reply #9 on: December 12, 2010, 08:35:44 AM »

Does anyone know if this problem was solved? I am having almost the
exact problem with the following differences:

This is my second experience with this problem on the same IC 207.
After my first experience with this problem, my radio did start working
for a while but I don't recall what change, if any, I made to cause it to
work. I was trying a lot of different things and suddenly, it started to work.
At the time, I thought the addition of a choke balun made it work
but I'm using one now and the problem continues.

When I make a transmission I can hear the power supply hum. I don't know what causes this.
 The hum seems to be the same regardless of
the power setting on the radio. I do not recall this happening when the 207 was working correctly. I've experimented with the distance between
radio and power supply and that doesn't change the hum. I've also tried
the radio on a newer, Astron power supply. On the Astron power supply, I
don't hear the hum but the radio continues to fail.

After the original problem was fixed, I used the IC 207 successfully for
several months. The problem only restarted when I switched from a dipole
antenna to a J-pole. Switching back to the dipole does not correct the
problem.



Any ideas will be greatly appreciated
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WB6BYU
Member

Posts: 13017




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« Reply #10 on: December 12, 2010, 08:56:10 AM »

I've also got an IC207 on the bench for a blown final amp.  Sometimes they will be intermittent,
or you might have a poor solder contact at the antenna connector that got jiggled when you
changed the antennas.

Troubleshooting the radio is a problem:  I wasn't able to connect the control head to the radio
once I pulled the case apart enough to access the amplifier module to take measurements.
(Of course I managed to blow out the voltage regulator in the control head while trying...)

Your best approach probably is to find a technically competent ham in the Sparks area to
help.  If you put the rig on low power simplex and can hear it on a HT nearby, then at least
you know that the rig is on frequency, and the problem likely is either the final amp or
something in the output stage between there and the antenna connector.  If the output
signal (at short range) gets stronger when you increase the power level, then the amp
probably is working.  (Don't put it all the way up to high power for this test, though.)

But this is why my IC207 is still sitting in a box instead of being fixed - it isn't easy to
troubleshoot the rig.  The most likely cause is a bad final amp module, but that isn't a cheap
thing to change out without further supporting evidence.   It also could be that the radio
is off frequency (in spite of the display) if something is wrong with the synthesizer, which
is why the preceding test is helpful. 
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KE7RTV
Member

Posts: 35




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« Reply #11 on: December 18, 2010, 09:15:44 AM »

Thanks for the help. It's a difficult problem to fix. Maybe it's time for a new radio.

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KE7RTV
Member

Posts: 35




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« Reply #12 on: January 23, 2011, 08:00:22 PM »

Hope this helps someone else... After a great deal of testing and experimenting the
problem turned out to be with the power supply. Changed to a new Alinco DM-330MV and
the problem went away.
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