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I have seen some 847 with the same problem, and there's a common thing, they all where using some interface for FT8.
Maybe an excesive audio or impedance problems, I dont know, fry something related to the modulation stage. There is a carrier, algo works in 2m, but in HF is gone, so SSB obvioulsy wont work. Have a tech friend with 3 847 with the same problem and cant proceed properly because cant find a decent service manual. Any help will be appreciated.
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How are you keying the rig?? If you key the rig with CAT, the audio
needs to come in from the mike plug in the front.? Key the rig via
the TRS jack, feeding audio in to the same, and it should work.?
Similarly, if you are doing VHF/UHF packet, key the rig and feed
audio into the DIN port.? For the TRS port, you'll need a resistor
and DC-blocking cap to merge the audio and PTT signals; it's the
same "interface" as is often used to interface to an HT.? The DIN
port has separate PTT and Audio pins, but it's for FM Packet.
For some unknown reason, keying the rig via CAT takes the audio from
the mike input, which is probably the least useful place to take it
from.
Greg? KO6TH
HI8RMQ via groups.io wrote:
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I have seen some 847 with the same problem, and there's a
common thing, they all where using some interface for FT8.
Maybe an excesive audio or impedance problems, I dont know,
fry something related to the modulation stage. There is a
carrier, algo works in 2m, but in HF is gone, so SSB obvioulsy
wont work. Have a tech friend with 3 847 with the same problem
and cant proceed properly because cant find a decent service
manual. Any help will be appreciated.
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Keying with CAT, but those radios are not in use anymore, the have no output in HF SSB. They have carrier in Fm, Am, but no modulation.
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Right.? If you key with CAT, but feed the FT-8 / Packet audio in
from the back, the audio will not reach the transmitter.? SSB will
have no output, and AM / FM will be carrier only.? The only way to
use CAT is to feed the audio in from the Mike jack in the front
(which is annoying).? Yaesu expects you to key the rig from the TNC
via the jacks on the back of the rig.? Look in the manual, pages 16
& 17.
If you key with CAT and then talk into the microphone, you should
see proper power and audio in all modes.
Greg? KO6TH
HI8RMQ via groups.io wrote:
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Keying with CAT, but those radios are not in use anymore, the
have no output in HF SSB. They have carrier in Fm, Am, but no
modulation.
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On more question if you key the transmitter with te mic in ssb, is it working?
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Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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Yes, but talking very loud you may get maybe 5w in SSB. In Fm (Hf only) or am, is barely audible. Carrier is good, 100W in Fm, but modulation almost gone. It works fine in vhf and uhf. Have 2 radios, same problem.
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Correct.? The audio is "basically" gone, down probably 50+ db.? I
was able to force a marginal FT-8 signal through from the back by
moving it from a "Line Out" jack on the PC to the Speaker out, and
cranking up the volume.? The radio survived doing this once, but I
do NOT recommend this.
What you describe is definitely a problem, but it's in the design
of the rig, not your particular copy.? All 847's behave this
way.? To use FT-8 or Packet radio you need to key the rig via the
same port the audio is coming in on (TRS for HF SSB, DIN for VHF/UHF
FM), and NOT use CAT for keying / PTT.? The alternative is to use
CAT for keying the rig, but wire your audio input into the Mike
connector on the front.? You choose one method or the other.? You
cannot do both (CAT for PTT, rear jacks for audio) with the 847.
Greg? KO6TH
HI8RMQ via groups.io wrote:
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Yes, but talking very loud you may get maybe 5w in SSB. In Fm
(Hf only) or am, is barely audible. Carrier is good, 100W in Fm,
but modulation almost gone. It works fine in vhf and uhf. Have 2
radios, same problem.
_._,_._,_
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Thank you very much. But now I cant use the radio on Ssb HF. Something can be done?
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How do you have things wired?? A pencil scribble diagram will help a
lot.
Greg? KO6TH
HI8RMQ via groups.io wrote:
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Thank you very much. But now I cant use the radio on Ssb HF.
Something can be done?
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Late to the party.? So from the sounds of it you have no modulation or very little in any mode.? SSB, AM, FM or data.? That should be rather easy to troubleshoot.? Just inject a audio signal (10mV at 1kHz) into the mic jack and signal trace the audio through the TX audio chain.? All you need is a oscilloscope or even a antique signal tracer will work.? Just follow the mic audio chain using the block diagram.
?
Mikes Radio Repair
KC3OSD
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Correct me please if i am wrong.
The TS says that there is no modulation in phone and in digital mode, on HF?
There is modulation on 2 meter, and 70 centimeter, in all modulation modes, digital and phone?
--
Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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Correct. The modulation in HF is very very low, talking very loud may give 3 or 4 w
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So no power in HF in FM mode? Then the fault is in the HF PA section, Q3002, or the preceding BPF.
--
Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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Further up the discussion he stated 100 watts FM on HF, so PA is fine. Perhaps the OP could clarify if any power on AM, CW and FM on HF, just so we are not getting confused.
So no power in HF in FM mode? Then the fault is in the HF PA section, Q3002, or the preceding BPF.
--
Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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Very low audio, so SSB on HF is at much 3W.
Powers on other modes all fine, AM, FM, CW, but theres no audio noticeable on FM or AM.
Just happens on HF.
?
?
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Great, if power output is ok on FM and CW then your PA is working. Do you have the same low SSB on VHF? Where were you feeding audio in to the rear? Which port on the back? Finally, what test equipment do you have?
Very low audio, so SSB on HF is at much 3W.
Powers on other modes all fine, AM, FM, CW, but theres no audio noticeable on FM or AM.
Just happens on HF.
?
?
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Please just make a video and post it as private on YouTube. Folks can then see exactly what’s going on and broach a comment.
De Spence G5STO Sent while portable! please excuse typos.
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On 20 Aug 2024, at 12:30, Andy Bosworth via groups.io <sidthepop@...> wrote:
? Great, if power output is ok on FM and CW then your PA is working. Do you have the same low SSB on VHF? Where were you feeding audio in to the rear? Which port on the back? Finally, what test equipment do you have? Very low audio, so SSB on HF is at much 3W.
Powers on other modes all fine, AM, FM, CW, but theres no audio noticeable on FM or AM.
Just happens on HF.
?
?
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HI8RMQ if you want us to point you at the possible fault. You have to gif answers to our questions consistently. And gif answers to what you are asked.?
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Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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This is the preamp area, the left top ic manages audio input into hf,vhf,and uhf.
Part is not clearly readable, but I think is Q1063 or Q1053.
?
Yellow line is the traced path from 1Khz audio input from mic.
Blue is the command data to control the audio to be output in the red line.
Red line measures noise, not the 1Khz signal as I think it should.
Maybe a more experienced mate could observer something from this.
?
?
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These chips were are current mirrors, you will not see the mic signal around here, look upstream towards the modulator and SSB filter.
73
Andrew
?Get BlueMail for Android ?
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On 21 Aug 2024, 03:57, at 03:57, "HI8RMQ via groups.io" <rafael_mota@...> wrote: This is the preamp area, the left top ic manages audio input into
hf,vhf,and uhf.
Part is not clearly readable, but I think is Q1063 or Q1053.
Yellow line is the traced path from 1Khz audio input from mic.
Blue is the command data to control the audio to be output in the red
line.
Red line measures noise, not the 1Khz signal as I think it should.
Maybe a more experienced mate could observer something from this.
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Mike KC3OSD
Andy Bosworth
Spence G5STO
Andrew Lenton