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I purchased an IC7000 with the condition that will not transmit on all HF bands. ?VHF/UHF transmit at the designed power out in all modes. ?Receiver works excellent in all bands all modes. ?Since VHF/UHF transmit proves that the Driver circuit works I have focused on the HF circuit. ?With a scope, I see hf signal through the driver and through the power transistors Q301 and Q302. ?The bias current is set properly. ?All board traces seem to be in-tack and pass the signal through to the ANT1 connector when terminated with a dummy load, but the signal barely registers on the external power meter when the power control is set to 100%.
Any help for further troubleshooting will be greatly appreciated.
Thanks
Tommy KF4RWG
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Measure the current from the power supply, if 18-20 odd amps then the power is being generated, but being lost in the RF LPF or certainly ?in that path, if current only 2-3 amps, then the HF pa transistors are not been driven! ? KR ? Andrew ?
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From: [email protected] <[email protected]> On Behalf Of Tommy Wooten via groups.io
Sent: 21 January 2025 00:35
To: [email protected]
Subject: [ic7000] IC7000 no HF Transmit? I purchased an IC7000 with the condition that will not transmit on all HF bands. ?VHF/UHF transmit at the designed power out in all modes. ?Receiver works excellent in all bands all modes. ?Since VHF/UHF transmit proves that the Driver circuit works I have focused on the HF circuit. ?With a scope, I see hf signal through the driver and through the power transistors Q301 and Q302. ?The bias current is set properly. ?All board traces seem to be in-tack and pass the signal through to the ANT1 connector when terminated with a dummy load, but the signal barely registers on the external power meter when the power control is set to 100%. Any help for further troubleshooting will be greatly appreciated.
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Double check for fuse oxidization if using the factory power cords.... Pop them out and re-insert etc.
Measure the current from the power supply, if 18-20 odd amps then the power is being generated, but being lost in the RF LPF or certainly ?in that path, if current only 2-3 amps, then the HF pa transistors are not been driven! ? KR ? Andrew ? ? I purchased an IC7000 with the condition that will not transmit on all HF bands.? VHF/UHF transmit at the designed power out in all modes.? Receiver works excellent in all bands all modes.? Since VHF/UHF transmit proves that the Driver circuit works I have focused on the HF circuit.? With a scope, I see hf signal through the driver and through the power transistors Q301 and Q302.? The bias current is set properly.? All board traces seem to be in-tack and pass the signal through to the ANT1 connector when terminated with a dummy load, but the signal barely registers on the external power meter when the power control is set to 100%. Any help for further troubleshooting will be greatly appreciated.
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Andrew,
I set each band to FM and measured the power supply current at each band.? I found that 160M measured 5 amps and 6M measured 20 amps.? The current increased from 160M to 6M in a linear fashion.? The external RF power meter never shows more than a few milliwatts at any of the bands.
Where should I measure the signal along the hf filter path?
Thank you so much.
Measure the current from the power supply, if 18-20 odd amps then the power is being generated, but being lost in the RF LPF or certainly ?in that path, if current only 2-3 amps, then the HF pa transistors are not been driven! ? KR ? Andrew ? ? I purchased an IC7000 with the condition that will not transmit on all HF bands.? VHF/UHF transmit at the designed power out in all modes.? Receiver works excellent in all bands all modes.? Since VHF/UHF transmit proves that the Driver circuit works I have focused on the HF circuit.? With a scope, I see hf signal through the driver and through the power transistors Q301 and Q302.? The bias current is set properly.? All board traces seem to be in-tack and pass the signal through to the ANT1 connector when terminated with a dummy load, but the signal barely registers on the external power meter when the power control is set to 100%. Any help for further troubleshooting will be greatly appreciated.
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Hi Andrew
do you know the full history of the radio?
There are many factors that could produce the results you describe.
The fact that the radio is drawing 20A at 6M means that power is being dissipated but not exiting the antenna port into a load.
" I found that 160M measured 5 amps and 6M measured 20 amps"
Something must be getting hot. A infrared camera would help detecting the hot areas
James
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I will check the circuit, set the power to 5% for safety
73
Andrew
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On 21 Jan 2025, 21:17, at 21:17, "Tommy Wooten via groups.io" <kf4rwg@...> wrote: Andrew,
I set each band to FM and measured the power supply current at each
band.
I found that 160M measured 5 amps and 6M measured 20 amps. The current
increased from 160M to 6M in a linear fashion. The external RF power
meter
never shows more than a few milliwatts at any of the bands.
Where should I measure the signal along the hf filter path?
Thank you so much.
On Tue, Jan 21, 2025 at 12:15?PM Andrew Lenton via groups.io <a=
[email protected]> wrote:
Measure the current from the power supply, if 18-20 odd amps then the
power is being generated, but being lost in the RF LPF or certainly in
that path, if current only 2-3 amps, then the HF pa transistors are not
been driven!
KR
Andrew
*From:* [email protected] <[email protected]> *On Behalf Of *Tommy Wooten
via groups.io
*Sent:* 21 January 2025 00:35
*To:* [email protected]
*Subject:* [ic7000] IC7000 no HF Transmit
I purchased an IC7000 with the condition that will not transmit on all HF
bands. VHF/UHF transmit at the designed power out in all modes. Receiver
works excellent in all bands all modes. Since VHF/UHF transmit proves that
the Driver circuit works I have focused on the HF circuit. With a scope, I
see hf signal through the driver and through the power transistors Q301 and
Q302. The bias current is set properly. All board traces seem to be
in-tack and pass the signal through to the ANT1 connector when terminated
with a dummy load, but the signal barely registers on the external power
meter when the power control is set to 100%.
Any help for further troubleshooting will be greatly appreciated.
Thanks
Tommy KF4RWG
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If there is a problem with the transmit chain before the forward / reverse power measurement circuit reducing the power may not change to amount of power drawn by the PA.
Most transceivers control the drive from the forward power measured by the For/Rev circuits.?
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True, but nothing is coming the aerial socket so there is an issue post PA and LPF probably a pin diode!
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On 22 Jan 2025, 13:35, at 13:35, "J.D. Barron via groups.io" <jeter.d.barron@...> wrote: If there is a problem with the transmit chain before the forward /
reverse power measurement circuit reducing the power may not change to
amount of power drawn by the PA.
Most transceivers control the drive from the forward power measured by
the For/Rev circuits.
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I received the radio in this condition.? The only evidence of rework from the previous owner was the rx/tx relay had been replaced.? Some of the thru holes for the relay leads had been disturbed.? Maybe the “no TX” issue was the reason the owner replaced the relay.? I removed the relay and closely inspected the traces and thru holes.? Everything seems to be intack.? As I mentioned, the receive works exceptional in all bands.? This tells me that all LPFs are working.? I tried the TX TOTAL GAIN adjustment procedure but no increase in power out. ? I am adding a couple of schematic views.? First is the rx/tx relay just beyond the PA circuit.? The second is the forward/reverse detector for the power control and SWR. ?
Thanks Tommy KF4RWG
True, but nothing is coming the aerial socket so there is an issue post PA and LPF probably a pin diode!
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On 22 Jan 2025, 13:35, at 13:35, "J.D. Barron via " <jeter.d.barron=[email protected]> wrote:
>If there is a problem with the transmit chain before the forward /
>reverse power measurement circuit reducing the power may not change to
>amount of power drawn by the PA.
>Most transceivers control the drive from the forward power measured by
>the For/Rev circuits.
>
>
>
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Ok, I have done some additional test at 10M where the supply current is around 15 amps.? When in FM TX, there is a quick rise in temperature on the surface of the board near the circuit of L303 located between the two power FETS.? Power setting has no affect on the results. ? Could there be an oscillation???
I have attached this portion of the schematic.
Any suggestions are appreciated
Thanks Tommy KF4RWG
I received the radio in this condition.? The only evidence of rework from the previous owner was the rx/tx relay had been replaced.? Some of the thru holes for the relay leads had been disturbed.? Maybe the “no TX” issue was the reason the owner replaced the relay.? I removed the relay and closely inspected the traces and thru holes.? Everything seems to be intack.? As I mentioned, the receive works exceptional in all bands.? This tells me that all LPFs are working.? I tried the TX TOTAL GAIN adjustment procedure but no increase in power out. ? I am adding a couple of schematic views.? First is the rx/tx relay just beyond the PA circuit.? The second is the forward/reverse detector for the power control and SWR. ?
Thanks Tommy KF4RWG
True, but nothing is coming the aerial socket so there is an issue post PA and LPF probably a pin diode!
?Get BlueMail for Android ?
On 22 Jan 2025, 13:35, at 13:35, "J.D. Barron via " <jeter.d.barron=[email protected]> wrote:
>If there is a problem with the transmit chain before the forward /
>reverse power measurement circuit reducing the power may not change to
>amount of power drawn by the PA.
>Most transceivers control the drive from the forward power measured by
>the For/Rev circuits.
>
>
>
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Hi Tommy
Check for open or short circuits after L305.
Open l306 or c337 or shorted c326
James?
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James I think you have a typo.? Instead of c337 I think you meant c327?? I have already checked for shorts and opens in this area.? It is interesting that the age of this unit does not have L306 and c326.? Later schematics (attached) do not have these components. One thing I have not checked is L305 for shorts or opens.? I would have to unsolder from the circuit to check this. I wonder if c319 or c320 could have an affect if open, ?I will check. One thing I have not mentioned is that r317 and r318 are dark from excess heat.? I did remove them and they both checked 10 ohms.? Possibly L304 is shorted or open?
I will report my findings.? Keep the ideas coming
Thanks Tommy
On Wed, Jan 22, 2025 at 5:55?PM James Tiberius via <nono2212000= [email protected]> wrote: Hi Tommy
Check for open or short circuits after L305.
Open l306 or c337 or shorted c326
James?
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Your schematic is somewhat different than mine . See attached.
Can I get a copy of your manual?
James?
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Looks like I can't attach a file?
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I will try to send you a link tomorrow.? There are 4 updates since the initial release.? Two in 2008, 2009 and 2010.
On Wed, Jan 22, 2025 at 8:26?PM James Tiberius via <nono2212000= [email protected]> wrote: Looks like I can't attach a file?
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Hi you need to see if there is RF before the LPF area, how is the RF board connected to filter board look there. As you changed bands check the LPF relays' actually energised.
RX received may be a red herring, as if we're stuck on 6M the RF at 80 m would whizz through uninpeaded.
I have two in the workshop when I get back I will make some measurements. On my working units.
The RX path,? may not go through the TX low pass filters, I will scower the circuit diagram and get back
RX normaly goes through band pass filters.
This is not an easy radio to work on, in fact one of the worst
73
Andrew
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On 22 Jan 2025, 18:30, at 18:30, "Tommy Wooten via groups.io" <kf4rwg@...> wrote: I received the radio in this condition. The only evidence of rework
from
the previous owner was the rx/tx relay had been replaced. Some of the
thru
holes for the relay leads had been disturbed. Maybe the “no TX” issue
was
the reason the owner replaced the relay. I removed the relay and
closely
inspected the traces and thru holes. Everything seems to be intack.
As I
mentioned, the receive works exceptional in all bands. This tells me
that
all LPFs are working. I tried the TX TOTAL GAIN adjustment procedure
but
no increase in power out.
I am adding a couple of schematic views. First is the rx/tx relay just
beyond the PA circuit. The second is the forward/reverse detector for
the
power control and SWR.
Thanks
Tommy KF4RWG
On Wed, Jan 22, 2025 at 8:50?AM Andrew Lenton via groups.io <a=
[email protected]> wrote:
True, but nothing is coming the aerial socket so there is an issue post PA
and LPF probably a pin diode!
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On 22 Jan 2025, 13:35, at 13:35, "J.D. Barron via groups.io"
<jeter.d.barron@...> wrote:
If there is a problem with the transmit chain before the forward /
reverse power measurement circuit reducing the power may not change to
amount of power drawn by the PA.
Most transceivers control the drive from the forward power measured
by
the For/Rev circuits.
|
This sounds like the output gets may be damaged, remove the drive and see what the current is, should fall the biased only
73
Andrew
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On 22 Jan 2025, 21:58, at 21:58, "Tommy Wooten via groups.io" <kf4rwg@...> wrote: Ok, I have done some additional test at 10M where the supply current is
around 15 amps. When in FM TX, there is a quick rise in temperature on
the
surface of the board near the circuit of L303 located between the two
power
FETS. Power setting has no affect on the results.
Could there be an oscillation???
I have attached this portion of the schematic.
Any suggestions are appreciated
Thanks
Tommy KF4RWG
On Wed, Jan 22, 2025 at 1:30?PM Tommy Wooten via groups.io <kf4rwg=
[email protected]> wrote:
I received the radio in this condition. The only evidence of rework from
the previous owner was the rx/tx relay had been replaced. Some of the thru
holes for the relay leads had been disturbed. Maybe the “no TX” issue was
the reason the owner replaced the relay. I removed the relay and closely
inspected the traces and thru holes. Everything seems to be intack. As I
mentioned, the receive works exceptional in all bands. This tells me that
all LPFs are working. I tried the TX TOTAL GAIN adjustment procedure but
no increase in power out.
I am adding a couple of schematic views. First is the rx/tx relay just
beyond the PA circuit. The second is the forward/reverse detector for the
power control and SWR.
Thanks
Tommy KF4RWG
On Wed, Jan 22, 2025 at 8:50?AM Andrew Lenton via groups.io <a=
[email protected]> wrote:
True, but nothing is coming the aerial socket so there is an issue post
PA and LPF probably a pin diode!
?Get BlueMail for Android ?
On 22 Jan 2025, 13:35, at 13:35, "J.D. Barron via groups.io"
<jeter.d.barron@...> wrote:
If there is a problem with the transmit chain before the forward /
reverse power measurement circuit reducing the power may not change
to
amount of power drawn by the PA.
Most transceivers control the drive from the forward power measured
by
the For/Rev circuits.
|
Hi,
You need to find out if there is RF power being generated.? The current is a clue, so switch to USB key up you should draw a few amps bias current, the speak CQCQ ect, the current should peak in sympathy with you voice. If it remains high you have a fault in the PS.
If the current remains the same check mic gain if ok, then you have no drive.
KR
Andrew
Get back to me
Do you have a spectrum analyser?
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On 23 Jan 2025, 01:33, at 01:33, "James Tiberius via groups.io" <nono2212000@...> wrote: Thanks Tommy
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Andrew Yes the current supply varies with usb modulation.? That is why I put the mode to FM for the supply current test.? The odd thing to me is that the supply current is substantially higher with the higher bands.? I do see a smaller but discernible ssb modulation in current at 160M. The FM transmit at 10M a quick rise in heat on the PCB near L303.? I do see a high level of RF at the output of each of the PA transistors and the level is substantially lower at the L305 output and down stream through the LPF to the ANT1.? As a result the output power at ANT1 is only milliwatts on the external power meter and dummy load.
I hope this description help's. ?
Thank you Tommy
Hi,
You need to find out if there is RF power being generated.? The current is a clue, so switch to USB key up you should draw a few amps bias current, the speak CQCQ ect, the current should peak in sympathy with you voice. If it remains high you have a fault in the PS.
If the current remains the same check mic gain if ok, then you have no drive.
KR
Andrew
Get back to me
Do you have a spectrum analyser?
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On 23 Jan 2025, 01:33, at 01:33, "James Tiberius via " <nono2212000=[email protected]> wrote:
>Thanks Tommy
>
>
>
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Andrew Lenton
