Re: [IC-7000] ALC question
Excessively high ALC on SSB will produce IMD, which can't be seen in the envelope displayed on a scope. You need a good spectrum analyzer to see the distortion products. Or have a nearby ham with a good receiver tune down the band an listen for your splatter.
ALC does introduce a non-linearity into the amplitude and phase of the signal, since it is changing the amplitude of the waveform (delayed by whatever the ALC circuit characteristics are).
Ignoring high ALC meter readings on SSB is not a recommended practice on any radio.
As previosuly mentioned, in constant-carrier modes, the ALC meter reflects how the overall TX loop gain is being controlled to maintain the TX Power Output setting, so full scale ALC meter readings is not necessarily a problem.
The ALC circuit is also used to limit TX power during several fault conditions: SWR > 2.5:1, forward power > 105 watts or current draw > 22 amps(due to low inpout voltage or a failing FET). These condtions will increase the ALC voltage bias to the IF stage, which reduces the power to the driver stage, to prevent damage to the PA FET's.
So if you are always seeing a high ALC level in SSB, regardless of mic gain settings, it may be due to one of the above condtions.
Steve, W3AHL
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--- In ic7000@..., "ludoradio@..." <ludoradio@...> wrote:
Le 21/12/2012 18:51, flashover_photography a ¨¦crit :
ok is the any way to adjust the ALC ? I'm ignoring the ALC... Mine go to high value but the
The oscilloscope show fine sigs and no problem in transmission.
73
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Hi Steve,
Thanks to your instructions I tried to troubleshoot the swr problem.
I monitored the IC960 and J2005-20 with some readings but nothing on the display. I also checked the ribbons with no results.
I will not go any further, unsoldering the bottom circuit plate, unless you have something else to suggest.
Despite this "minor" problem the rig is a fine piece of radio.
Thank you for your precious help.
Best regards and Merry Christmas to you and your family.
Georges SV1MOZ
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--- In ic7000@..., "Steve W3AHL" <w3ahl@...> wrote:
You will need a Service Manual to do any troubleshooting. The SWR detector (D962) and bufffer amp (IC960) are easily accessed on the bottom of the PA board by just removing the bottom cover. They are near the ANT1 connector corner of the board by the grounding fingers.
IC960 pin 1 outputs the HF reflected power signal and could be monitored with a DVM.
That voltage goes to the LOGIC card via two stacking connectors, then to the CPU as REFL signal, which results in the SWR meter display value. It can be monitored on the MAIN board at J2005-20, by removing the top cover. It is near the front of the board on the top side. If the signal is good there, then the problem could be the stacking connector to the LOGIC board or the CPU. I don't suggest trying to troubleshoot any further unless you are experienced with surface mount components, ESD protection, etc.
If the SWR display is not working, it is also possible that the SWR power foldback protection circuit is not working, which could result in damage to the HF PA FET's if the SWR is greater than 3:1. So, be careful until the problem is resolved.
It is suggested that you include your call sign in your posts....
Steve, W3AHL
--- In ic7000@..., "baulard69" <georges@> wrote:
Hi,
I resetted thi rig but nothing, no swr! All other meters are working fine.
Who could tell me were to look on the board?
Thank you for your time!!
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Re: Strange issues with output power
Hello everyone, 14 days ago i ran in the same problem.
Took my radio to a A licensed friend of mine for doing some QSO in JT65 in 20m. RF power set at 30 watt, modulation level adjusted, swr was fine. After a while we noticed very low power on the display.
We did a factory reset but no change.
First thought PA stage get burned, then we made some test.
We measured the following results.
1,9 MHz 0,8 Watt
3,55 MHz 1 Watt
7,05 MHz 5 Watt
10,12 MHz 28 Watt
14,1 MHz 30 Watt
15 MHz 35 Watt
18,1 MHz 30 Watt
21,2 MHz 35 Watt
24,95 MHz 40 Watt
28,5 MHz 60 Watt
50,1 MHz 25 Watt
2m/70cm are not affected.
First it seems the filterboard does something stupid, but then we noticed
the ALC display did not show correct, except on 10m.
Very strange behavior.
I did not try to repair the radio because it is still in warranty.
So radio is sent back to the seller for repair.
Today i got a call from him and apparently the driver stage got toasted.
Now i have to wait until second week in January.
I'm curious what comes out in your research.
73 de DO1KLM
Sigi
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Re: [IC-7000] ALC question
Le 21/12/2012 18:51, flashover_photography a ¨¦crit : ok is the any way to adjust the ALC ? I'm ignoring the ALC... Mine go to high value but the The oscilloscope show fine sigs and no problem in transmission. 73
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Re: [IC-7000] ALC question
On Fri, 21 Dec 2012 18:51:23 -0000, flashover_photography wrote: ok is the any way to adjust the ALC? and or how does it work? If I reduce the output power from 100W the ALC goes into the red? Generally speaking, mic gain controls ALC level on SSB, and carrier level controls it on carrier modes (cw/am/etc). If you lower power, ALC goes up on most rigs. Just reduce the drive, be it carrier or audio. Gary -- Web: NodeOp Page: Node 3055:
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Re: [IC-7000] Strange issues with output power
George - after reviewing your earlier post more carefully, your problem is
not the same as the one I had. I did have lower power output on 80 and
160, but not as dramatic as you explained.
But for your info, the repair cost was about $200.
73, John
K9EL
_____
From: ic7000@... [mailto:ic7000@...] On Behalf Of
George
Sent: Thursday, December 20, 2012 6:07 PM
To: ic7000@...
Subject: Re: [IC-7000] Strange issues with output power
Ivan,
Thanks, this is exactly what I had thought. I had guessed that the 10 metre
filter is always connected, and is dumping the RF from the other bands.
I will have a nose over the weekend and report back once I've found it.
Thanks.
George, M1GEO.
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Thank you Steve for your "in depth" reply, I really appreciate!!
Thankfully I have a sx-600 who monitors my tx.
I also have the service manual so I'll have a look as per your instructions.
Best regards
Georges SV1MOZ
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--- In ic7000@..., "Steve W3AHL" <w3ahl@...> wrote:
You will need a Service Manual to do any troubleshooting. The SWR detector (D962) and bufffer amp (IC960) are easily accessed on the bottom of the PA board by just removing the bottom cover. They are near the ANT1 connector corner of the board by the grounding fingers.
IC960 pin 1 outputs the HF reflected power signal and could be monitored with a DVM.
That voltage goes to the LOGIC card via two stacking connectors, then to the CPU as REFL signal, which results in the SWR meter display value. It can be monitored on the MAIN board at J2005-20, by removing the top cover. It is near the front of the board on the top side. If the signal is good there, then the problem could be the stacking connector to the LOGIC board or the CPU. I don't suggest trying to troubleshoot any further unless you are experienced with surface mount components, ESD protection, etc.
If the SWR display is not working, it is also possible that the SWR power foldback protection circuit is not working, which could result in damage to the HF PA FET's if the SWR is greater than 3:1. So, be careful until the problem is resolved.
It is suggested that you include your call sign in your posts....
Steve, W3AHL
--- In ic7000@..., "baulard69" <georges@> wrote:
Hi,
I resetted thi rig but nothing, no swr! All other meters are working fine.
Who could tell me were to look on the board?
Thank you for your time!!
|
ok is the any way to adjust the ALC? and or how does it work? If I reduce the output power from 100W the ALC goes into the red?
|
You will need a Service Manual to do any troubleshooting. The SWR detector (D962) and bufffer amp (IC960) are easily accessed on the bottom of the PA board by just removing the bottom cover. They are near the ANT1 connector corner of the board by the grounding fingers.
IC960 pin 1 outputs the HF reflected power signal and could be monitored with a DVM.
That voltage goes to the LOGIC card via two stacking connectors, then to the CPU as REFL signal, which results in the SWR meter display value. It can be monitored on the MAIN board at J2005-20, by removing the top cover. It is near the front of the board on the top side. If the signal is good there, then the problem could be the stacking connector to the LOGIC board or the CPU. I don't suggest trying to troubleshoot any further unless you are experienced with surface mount components, ESD protection, etc.
If the SWR display is not working, it is also possible that the SWR power foldback protection circuit is not working, which could result in damage to the HF PA FET's if the SWR is greater than 3:1. So, be careful until the problem is resolved.
It is suggested that you include your call sign in your posts....
Steve, W3AHL
toggle quoted message
Show quoted text
--- In ic7000@..., "baulard69" <georges@...> wrote:
Hi,
I resetted thi rig but nothing, no swr! All other meters are working fine.
Who could tell me were to look on the board?
Thank you for your time!!
|
Hi,
I resetted thi rig but nothing, no swr! All other meters are working fine.
Who could tell me were to look on the board?
Thank you for your time!!
|
Re: [IC-7000] Strange issues with output power
If you have access to a signal generator, you can eliminate the driver and PA by testing RX sensitivity on each band, since the same filters and switching logic are used in RX as in TX mode.
All of the LPF relay states can be checked from the bottom of the PA board without removing it.
The 10M HPF control signal (B6) state can be checked at the input steering diode D211 on the top of the MAIN board, where it connects to L240.
Many of the other HPF's have some control signal accessible from the top of the MAIN board, although the driver for the B1-7 control signals (IC2151) is under the logic unit.
Steve, W3AHL
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--- In ic7000@..., "George" <george.smart1@...> wrote:
Ivan,
Thanks, this is exactly what I had thought. I had guessed that the 10 metre filter is always connected, and is dumping the RF from the other bands.
I will have a nose over the weekend and report back once I've found it.
Thanks.
George, M1GEO.
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Re: [IC-7000] Strange issues with output power
Ivan,
Thanks, this is exactly what I had thought. I had guessed that the 10 metre filter is always connected, and is dumping the RF from the other bands.
I will have a nose over the weekend and report back once I've found it.
Thanks.
George, M1GEO.
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Re: [IC-7000] Strange issues with output power
John, that's not exactly the news I wanted, but I guess it's start... I wonder if that was replaced under warranty, or, did you pay? If you paid, any idea how much it cost you?
Cheers.
George, M1GEO.
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Re: [IC-7000] Re: IC700 and THP HL550FX
I use a THP HL-550FX with an IC7000 on trips and it works great. The IC7000 will key the HL550 directly. I do not use the ALC connection as I received bad reports with it connected. The ALC feedback form the amp and the internal ALC appeared to be battling each other. If you turn down the IC7000 output power so as not to exceed the HL550 ratings and keep the ALC readings on the radio in the proper range, you will be fine. 73, John K9EL _____ From: ic7000@... [mailto:ic7000@...] On Behalf Of Steve W3AHL Sent: Wednesday, December 19, 2012 2:43 PM To: ic7000@... Subject: [IC-7000] Re: IC700 and THP HL550FX The ALC cable would have its center pin connected to ACC-6 (blue) and shield to ACC-2 (red). The STBY cable whould have its center pin connnected to ACC-3 (orange) and shield to ACC-2 (red which is ground) [NOT to gray which is 13.8 VDC]. The HL550FX manual and spec sheet does not speciify the current draw of its T/R relay. But they do mention they are minature high speed Panasonic relays, which are all under 100 ma. (>40 ma. typical), well under the 7K's spec of 200 ma. Steve, W3AHL --- In ic7000@... <mailto:ic7000%40yahoogroups.com> , Richard Wiklund <richard@...> wrote:
I'd like to use my THP 550 watt amp with my Icom 7000. The diagram on page
21 of the Icom 7000 manual is not very clear. The amp has the ALC and STBY inputs, as shown in the diagram. And I have the13 wire cable supplied with the IC7000. Connecting the blue wire to the ALC is clear. The THP manual says, ""Connect the control cable from the ACC terminal (or SEND, TX GND etc.) of the transceiver. The center pin is to be shorted to ground through the relay circuit of the transceiver." Does the IC7000 have an internal relay? Do I connect the orange HSEND cable to the center pin of an RCA cable and the gray to the shield? Appreciate any help. Dick, K1MGH
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Re: [IC-7000] Strange issues with output power
George - I had almost an identical problem - low power output on the lower
frequencies, plus distorted audio on the lower frequencies on SSB. I sent
the radio to Icom and they replaced one of the final devices which was
"leaky" (their words). Radio works fine now.
73, John
K9EL
_____
From: ic7000@... [mailto:ic7000@...] On Behalf Of
George
Sent: Thursday, December 20, 2012 12:30 PM
To: ic7000@...
Subject: Re: [IC-7000] Strange issues with output power
I should point out that I have done a full reset (power up plus band up and
band down). The radio is powered by a 50 amp 13.8 volt power supply - I am
aware that the rig is sensitive to voltage changes (I've used it on
batteries) - This is a fault, but not the PA. I guess something like a relay
stuck in the LPF or a capacitor has died?
The fact the radio will do 95 watts on 10 metres implies it's fine.
Any advice greatly received.
George, M1GEO.
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Re: [IC-7000] Strange issues with output power
This is what I thought, regarding the power issue. I had terrible issues with the fuses on the power cable, when running from batteries - I was loosing 2 volts across the two fuses, but this was a long while ago. This is a new fault. It's definitely a fault, I'm a competent electronic engineer, and will look into this myself before sending it back to Icom.
I'm not so sure about it being a disconnected capacitor. The power goes up with frequency which does indicate some kind of capacitance issue, but I would then expect the full power out on 6 metres too, but I don't see this.
I also expect it to be in the final stage. If it was in the driver, then 2 metres and 70 centimetres would be questionable too.
Again, it's not a power supply issue, and the PA okay.
Thanks for the tips so far; seasons greetings...
de M1GEO.
-.-
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Re: [IC-7000] Strange issues with output power
Considering the power output is directly related to frequency, I'd guess
that you are correct in assessing a bad or disconnected capacitor, probably
in the excitation/driver section somewhere. Poor supply power is not a
likely issue, since output is normal on some bands.
Randy - K5MW
From: ic7000@... [mailto:ic7000@...] On Behalf Of
George
Sent: Thursday, December 20, 2012 11:42 AM
To: ic7000@...
Subject: [IC-7000] Strange issues with output power
Hi All.
I have had an Icom IC-7000 for over a year now, having bought it second
hand. Today I went to use the for a few SSB QSOs on 20 metres when I
realised I couldn't get more than 40 watts out.
Initially I thought that the PA amp may be at fault, but after playing
around some more, I learned that the power I get varies wildly with band.
Setting the radio to 100% power out, I get the following measured powers
with a Bird Thruline into a dummy load:
- 160 metres, 1 watt.
- 80 metres, 1 watt.
- 40 meters, 10 watts.
- 20 metres, 40 watts.
- 12 metres, 60 watts.
- 10 metres, 90 watts.
- 6 metres, 30 watts.
- 2 metres, 49 watts (fine).
- 70 cms, 37 watts (fine).
It seems the issues are in the HF PA, i.e. anything on Antenna 1. I'm not
sure what the issue is. I think something like a capacitor gone down, or a
relay stuck? I'm not sure.
Any help would be greatly received.
Thanks in advance.
George Smart, M1GEO.
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Re: [IC-7000] Strange issues with output power
Sounds strange but if you?have the original fuses better try cleaning them..? They will cause voltage drop when u transmit.???
Click on this to find?Bob & Carolyn's??position:??
??
From: George <george.smart1@...>
To: ic7000@...
Sent: Thursday, December 20, 2012 10:42 AM
Subject: [IC-7000] Strange issues with output power
?
Hi All.
I have had an Icom IC-7000 for over a year now, having bought it second hand. Today I went to use the for a few SSB QSOs on 20 metres when I realised I couldn't get more than 40 watts out.
Initially I thought that the PA amp may be at fault, but after playing around some more, I learned that the power I get varies wildly with band. Setting the radio to 100% power out, I get the following measured powers with a Bird Thruline into a dummy load:
- 160 metres, 1 watt.
- 80 metres, 1 watt.
- 40 meters, 10 watts.
- 20 metres, 40 watts.
- 12 metres, 60 watts.
- 10 metres, 90 watts.
- 6 metres, 30 watts.
- 2 metres, 49 watts (fine).
- 70 cms, 37 watts (fine).
It seems the issues are in the HF PA, i.e. anything on Antenna 1. I'm not sure what the issue is. I think something like a capacitor gone down, or a relay stuck? I'm not sure.
Any help would be greatly received.
Thanks in advance.
George Smart, M1GEO.
[Non-text portions of this message have been removed]
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Re: [IC-7000] Strange issues with output power
I should point out that I have done a full reset (power up plus band up and band down). The radio is powered by a 50 amp 13.8 volt power supply - I am aware that the rig is sensitive to voltage changes (I've used it on batteries) - This is a fault, but not the PA. I guess something like a relay stuck in the LPF or a capacitor has died?
The fact the radio will do 95 watts on 10 metres implies it's fine.
Any advice greatly received.
George, M1GEO.
|
Re: [IC-7000] Strange issues with output power
Try a full reset On Dec 20, 2012, at 12:42 PM, "George" <george.smart1@...> wrote: Hi All.
I have had an Icom IC-7000 for over a year now, having bought it second hand. Today I went to use the for a few SSB QSOs on 20 metres when I realised I couldn't get more than 40 watts out.
Initially I thought that the PA amp may be at fault, but after playing around some more, I learned that the power I get varies wildly with band. Setting the radio to 100% power out, I get the following measured powers with a Bird Thruline into a dummy load:
- 160 metres, 1 watt.
- 80 metres, 1 watt.
- 40 meters, 10 watts.
- 20 metres, 40 watts.
- 12 metres, 60 watts.
- 10 metres, 90 watts.
- 6 metres, 30 watts.
- 2 metres, 49 watts (fine).
- 70 cms, 37 watts (fine).
It seems the issues are in the HF PA, i.e. anything on Antenna 1. I'm not sure what the issue is. I think something like a capacitor gone down, or a relay stuck? I'm not sure.
Any help would be greatly received.
Thanks in advance.
George Smart, M1GEO.
[Non-text portions of this message have been removed]
|
Steve W3AHL