Kurt,
No, the problem is not primarily frequencies above 5KHz, but possibly an overal increase in all audio frequencies that pass through the selected BP filter (200-4000 Hz).? But I haven't heard your noise, so perhaps I'm wrong.? 6 KHz is a pretty high pitch.? If you have a scope to look at the level shift that would give you some idea.? Or better, if you have a computer with a Line level audio input (some mic inputs will auto switch to line, but many won't.? Check the manual) then you can download the free EasyRTA software that I used and see the frequency and amplitue.? It won't be as accurate as the Focusrite interface I use, but fine for this purpose.??
One easy check I thought might be worthwhile is measuring the AGC voltage that varies the IF stages gain.? But it maxes out at 4.6 VDC for signals below -60 dBm, which is well above having no coax connected, so not likely to lend any insight in your case!? And in case anyone every needs to troubleshoot AGC problems, the AGC voltage at the 3 IF stages should be about 3.4 VDC at -50 dBm, 2.5 VDC at -20 dBm and 2.1 at 0 dBm.? FYI S9 = -73 dBM, S9+60 = -13 dBm with pre-amp OFF.? The easist place to measure AGC is near Q702 on the top of the MAIN.? Put the probe tip in the open via hole on the trace that connects R713 and?C711 together.? Use the existing soldered bare wire connecting two nearby IF coil shields cans as ground.
I don't know what test equipment you have, but any further troubleshooting takes more than a DVM and scope probably.? If your increased "hiss" is actually a higher frequency squeal, then that might be easier to look into.
Steve, W3AHL
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Here is another completely different direction. And the benefit ,even f it doesn’t help the problem, it will be good maintenance . Snug all circuit board mounting screws for best ground possible. I added the proper size star washer to mine to ensure the best possible connection. Also check all ribbon cables to insure they are fully seated and not skewed . I learned this as my memory control knob on my 746 Pro would only advance in one direction after about an hours use. During this period ?with the 7000 and 746 and Pro and all radios of that era were the two maintenance items that were the main source of warranty returns to Icom.
Possibly the hiss comes from the signal not being lined up properly with the SSB filter.
If the frequency is low in relation to the filter it will pass higher frequency noise.?
Some radios have if offset and you can hear this in real time.
A check of the LOs etc might help determine if this is the case.?
It has been a while since I have looked at the IC-7000 block diagram or schematic, but it could be an answer.?
Does this happen in AM FM CW in addition to SSB?
-- Rick
For long you live and high?you fly and smiles you'll give?and tears you’ll cry and all?you touch and all you see is?all your life will ever be
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There is an Icom service
bulletin on this. AM-100606C-ID lists one .01uFd capacitor and an insulating
sheet behind IC2602, the audio amplifier. The capacitor is on the input to the
amp. It’s an LA-4425A which is pretty common.
?
Thank You
?
Paul W. Hansen, W6XA
Amateur Radio Service
2134 Carthage Road
Tucker, GA 30084
(864) 222-3539
www.amateurradioservice.com
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Steve W3AHL
Sent: Saturday, April 15, 2023 04:49
To: [email protected]
Subject: Re: [ic7000] IC7000 Audio Hiss
?
Kurt,
I did some testing with my 7K (and an Elecraft K3), measuring audio noise
levels on different bands with the pre-amp OFF and ON using an analyzer.?
I have a report with spectrographs, but forgot we can't post attachments in
this group.? If you email me at w3ahl at att dot net, I will send you a
copy.? It's about a 1.4 MB PDF file.
My unit doesn't seem to exhibit your problem and the hiss level is comparable
to a K3.? The hiss on UHF is definitely higher though with the pre-amp on.
I haven't worked on any units with this problem, so I can't help point you to
some common cause.? You would need an analyzer to track the signal.?
But if it's on all bands, including VHF & UHF, then it's probably in the IF
or DSP circuits, which are a bear to work on.
Steve, W3AHL
|
Possibly the hiss comes from the signal not being lined up properly with the SSB filter.
If the frequency is low in relation to the filter it will pass higher frequency noise.?
Some radios have if offset and you can hear this in real time.
A check of the LOs etc might help determine if this is the case.?
It has been a while since I have looked at the IC-7000 block diagram or schematic, but it could be an answer.?
Does this happen in AM FM CW in addition to SSB?
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Possible to reduce the hiss like this :
(use google translate)
Best regards,
Ludovic - F5PBG
(Youtube, etc...)
|
Steve,
Thanks for the info.
Would it be possible to purchase or construct a cut off filter, say at 6-7 KHz and simply put it at the speaker?
Kurt
KD6LZV
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Kurt,
I did some testing with my 7K (and an Elecraft K3), measuring audio noise levels on different bands with the pre-amp OFF and ON using an analyzer.? I have a report with spectrographs, but forgot we can't post attachments in this group.? If you email me at w3ahl at att dot net, I will send you a copy.? It's about a 1.4 MB PDF file.
My unit doesn't seem to exhibit your problem and the hiss level is comparable to a K3.? The hiss on UHF is definitely higher though with the pre-amp on.
I haven't worked on any units with this problem, so I can't help point you to some common cause.? You would need an analyzer to track the signal.? But if it's on all bands, including VHF & UHF, then it's probably in the IF or DSP circuits, which are a bear to work on.
Steve, W3AHL
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The VA3IUL fix would seem to only apply to FM signals, since the cap is added to the FM -6dB/octave de-emphasis circuit.? Audio for other modes (CW, SSB, AM) is fed from IC2551 pin 1 to the audio switch at IC2601, which precedes modification.
Perhaps a similar mod across C2564 instead would roll off the high frequency audio for CW/SSB modes.??
Fortunately my ears have developed built-in HF attentuators....?
Steve, W3AHL
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not sure but there have been 7k's that have a higher freq hiss?
?
https://www.qsl.net/va3iul/Files/IC7000_audio_noise.pdf
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My 7000 seems to have developed a strong hiss in the receive mode. Originally, I thought it was is atmospheric but the noise didn’t change when the coax was disconnected.?
some details that help diagnosis:
Hiss is pretty much the same across HF and VHF; ?1.8 and 435 MHZ are the worst.
Pre amp makes it much worse, as expected
This has been getting worse or a period of time; gradually developing not sudden onset
Any thoughts, ?such a list of usual suspect components,appreciated
Kurt
KD6LZV
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Looking for parts radios...
GL es 73
John KR?P
Sent: Thursday,
April 13, 2023 at 3:44 PM
Subject:
[ic7000] IC-7000 for sale
In case you're looking for one. It's not mine, I just came across
the ad.
--
John Mardock
j@...
j@...
402-525-6111
|
In case you're looking for one. It's not mine, I just came across the ad.
|
Re: IC-7000 not stable on 10 & 14 MHz into reactive load
I haven't seen this problem before, but did check my two 7K's ( circa 2006 & 2010) per your description and don't see anything similar.??
?
I suggest looking at the output of the Driver board to see if the spurs are present there and if so, check the YGR amp output at its coax connection on the bottom of the PA board (see lower right corner of the PA top & bottom PCB artwork for location).? It is possible the spurs you are seeing are generated in the front end TX circuits, rather than being a problem with the LPF's.
I did work on one very early unit (circa 2005) that had stability problems in the YGR amp (IC1 on the Main board) .? This was partly caused by poor connection of the two small coaxial? cables' shields that plug into the top of the Main board.? Wiggling the YGR cable slowly would cause the instability to come and go.? I replaced the cables with new ones, which made a big improvement.? I believe there are additional issues in the 2005 units with the PCB artwork layout around the YGR IC1 circuit on the Main board.? Later revisions had changes to trace routing and ground planes which aren't practical to implement with rework.? This circuit is very hard to troubleshoot, since putting a scope probe on areas of interest affected the stabilty.? But on this one unit the problems I saw were 28 Mhz through UHF I believe.
The HF PA's are most efficient in the 10-14 MHz, as evident by looking at the Driver output voltage across all bands.? It might be useful to check ihe TX Adjustments, especially for the TX Peak and TX Total Gain (HF2).? Checking the Driver and Final Idle currents can sometimes reveal a problem that isn't obvious also.
There is a mod to the Driver board suggested by F6CIS and documented by F5DQK that changes a C101 on the Driver board form 0.01uf to 0.1uf to prevent self-oscillations.? I haven't evaluated it, but have repaired several 7k's that seemed to fail when operating at low power and into reactive antennas using an autotuner.? I was never able to recreate the problem on my bench, so I didn't pursue the C101 change.??
Good luck and please post any progress you make.
Steve, W3AHL
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IC-7000 not stable on 10 & 14 MHz into reactive load
Hello,
I am new to this group. I did try to send this before and I didn't see it pop up in the list so apologies if it comes up twice.?
I have been looking at a crook IC-7000 for a friend of mine which has an issue on TX on 10 and 14 MHz. 14 MHz seems to be unstable into a reactive load. Works ok on a good dummy load.
I initially suspected the low pass filter (LPF) section especially surrounding the 10 & 14 MHz part as these two bands share the same filter section.
I looked at the radio on the spectrum analyser and see that 14 MHz has the fundamental and two spurs flicking between 2 – 10 dB down from the fundamental.
I note on SSB with no modulation and the radio set to its lowest power into a reactive load or even an open circuit it will take off and put out power and oscillating at around 12 MHz. 10 MHz will do the same but oscillates at 11 MHz. This only appears on these two bands only, all others OK. The placement of those two pink rubber pads has an effect on stability as well and I found the ones in this radio were in the wrong place.
I have been through the relay driver logic and looked / tested the relay crossover points where it switches bands. All relays picking where they should be. Also tested continuity from the input of the LPF to the input of the SWR detection transformer and I have good continuity and can see the blips in the continuity as I change bands so looks like the coils in the LPF are good.
?
It’s a weird one.. Haven’t pulled the PA board off yet, just doing pre-tests before I rip into it.
Any ideas about this problem would be useful and maybe someone has seen this before. I am suspecting caps in the LPF. The local ICOM repairer has looked at it and couldn’t fix it.
Cheers & 73,
Simon
ZL1SWW
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IC-7000 not unconditionally stable on 10 & 14 MHz
Hello,
I am trying to fix a friend's 7000 that is iffy on TX on 10 & 14 MHz.
I immediately think that there maybe an issue with the LPF relays / components on these bands as I see that the 10 and 14 MHz are sharing the same LPF section. All other? HF bands are stable.?
Looking on the specan when running a reactive load shows lower output with spurs flicking? around 2- 10 dB lower than the fundamental. It doesn't show it on 10 MHz at all. with no modulation on USB and no load it will oscillate at around 12 MHz.
Into a proper dummy load it seems to be fine.?
I haven't pulled the PA board yet to see if I have bad caps etc in the LPF section. Checked all the logics and the appropriate relays are picking for the correct band.?
One thing i noticed is that thiose pink rubber pads have to be ina specific place to help stop the oscillation. Had a situation before on 20 m where the radio would click off and reboot with no mod and on the lowest power setting with a reactive load.
My own IC-7000 seems stable as when doing the similar tests.?
Still suspecting omething in the LPF and relay continuity for that band and all others seems OK whne stesing with a DMM. Maybe crook caps?
Any ideas / experiences with this?? The local ICOM repairer couldn't fix or find anything.
Thanks,
Simon
ZL1SWW
|
Re: Looking for a Replacement
As much as I love my IC-7000, the form factor question is easy.? The IC-7000 has a bunch of menus (3 groups of 3) and the screen is fairly small (for old eyes).? I also have three IC-7100 units.? With the additional buttons and large touch screen, there are fewer menus despite a large number of additional features.? The IC-7100 is an easier radio to use and the head is entirely self-contained with a microphone jack, key jack and internal speaker.??
The IC-7100 head has two different mounting options.? It does have a 1/4x20 tripod-style thread mount AND a three screw mount for Icom's adjustable mount.? The 1/4x20 thing supports a variety of GoPro and RAM mount options.? There are also 3D printable mounting options specifically designed for the IC-7100 at?.? It is a more complicated form factor to accomodate but there is a larger variety of mounting options available.
Scott N7SS
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Re: Looking for a Replacement
I was afraid that might be an issue. Never have understood why Icom went to that form factor. Could have at least put a? 1/4‐20 tripod mount on it.
73 Joe KR0UT?
The remote head of the IC7000 is key. While a 7100 would be nice, it would take up real estate at the nav station desk.?
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Re: Looking for a Replacement
The remote head of the IC7000 is key. While a 7100 would be nice, it would take up real estate at the nav station desk.?
|
Yes sometimes it is - and I believe I
found something now;
When pulling out the plug for my cw-key from the jack at the
transceiver back, the keyer then started to work as expected.
Looking in the manual, it is suggested to use a stereo plug with
the middle tab left unconnected, when using a straight key. I had
a mono plug.
After changing to the connection the manual suggests I can now
both key with my straight key and use the keyer memories.
So the keyer doesn't work when one of the paddle connections are
grounded in the plug. Even though straight key is selected in the
settings of the radio. This is a software bug I believe.
73 Daniel SM6VFZ
?
On 4/3/23 22:46, Steve Murphy wrote:
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Show quoted text
Well,
sometimes it's the simple things we overlook. Just thought I'd
throw that out there.
Very odd.
My 7000 CW memories do not make a button press confirmation
beep. Just sends the stored message.
Perhaps a
processor reset would solve the issue.
- Steve
KC4SM
Sure, that I know and are aware of. But it is the same
behavior in all modes.
/SM6VFZ
Den m?n 3 apr. 2023
15:13Steve Murphy < KC4SM@...>
skrev:
Make sure the
radio mode is CW. Any other mode and you won't
hear the side tone.
73
de KC4SM
Hi group,
I am trying, and trying, to get the CW keyer
memories play. But they simply won't.
I can set the content of the four memories
without problem, but when going into
KEY->SND and then pushing an F-key for any
of the memories it produces just a normal
button beep. It does not play the CW message.
Anyone having a clue about what could be wrong
here?
Thanks,
Daniel SM6VFZ
|
Well, sometimes it's the simple things we overlook. Just thought I'd throw that out there. Very odd. My 7000 CW memories do not make a button press confirmation beep. Just sends the stored message. Perhaps a processor reset would solve the issue. - Steve KC4SM
Apr 3, 2023 11:17:24 AM Daniel Uppstr?m <vfz.daniel@...>:
toggle quoted message
Show quoted text
Sure, that I know and are aware of. But it is the same behavior in all modes.
/SM6VFZ
Den m?n 3 apr. 2023 15:13Steve Murphy < KC4SM@...> skrev:
Make sure the radio mode is CW. Any other mode and you won't hear the side tone. 73 de KC4SM
Hi group,
I am trying, and trying, to get the CW keyer memories play. But they simply won't.
I can set the content of the four memories without problem, but when going into KEY->SND and then pushing an F-key for any of the memories it produces just a normal button beep. It does not play the CW message.
Anyone having a clue about what could be wrong here?
Thanks,
Daniel SM6VFZ
|
Steve W3AHL
Ludovic Ludo
Roeland Jansen, PA3MET
Danny K5CG
Scott Honaker