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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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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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.
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Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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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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Correct. The modulation in HF is very very low, talking very loud may give 3 or 4 w
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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?
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Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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Re: Receiver Audio Volume
Receivers ok.
Problem is on HF, all bands.
Audio input management? is indepent for HF, VHF, UHF, so I guess the module that handles the HF audio is bad somewhere. Sadly I dont have a signal tracer.
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Re: Receiver Audio Volume
Does the receive signal strength also increase?? Is it the same on every band or only one band.? It could be dirty/arced relay contacts or a relay with bad solder joints (common on most HF rigs of the era).? There are relays for each band to switch in and out the band pass filters and there are RX/TX relays.
?
Mikes Radio Repair
KC3OSD
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Re: Receiver Audio Volume
First of all check your powerkabel, connectors, fusses, and fuse holders, for bad contacts.
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Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.
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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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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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Thank you very much. But now I cant use the radio on Ssb HF. Something can be done?
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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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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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I have noticed that I can have the 847 on for a while and then when key the CW key, the speaker volume suddenly increases.? Anybody else experience this?? It don't know if the receive sensitivity has gotten better or not.
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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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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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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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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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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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Andy Bosworth
Mike KC3OSD