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GEN mode probelm
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Hi, friends, I have noted in my FT980, in GEN mode, at any frenquency when I active TX in USB the current in the final state (METER I), rise uo to 10 A, even without audio in microphone and DRIVE and MONI en minimun. In LSB the current is zero, normal. Any hint to this anomaly? Tnx.... CP6CL - JOSE Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525 |
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Hello Jose, I checked this scenario on my FT-980 and it is not doing that.? I tried to key up on 14.005 and 14.5 MHz. No Ic current in any mode, on any freq. Have you had this radio since new?? If not, then you could have a CB mod for GEN TX.? They did that to get on 11m USB back in the days. 73, Wald N4PL
On Friday, May 29, 2020, 11:27:32 PM EDT, jose carlos leon via groups.io <josecarlosleon48@...> wrote:
Hi, friends, I have noted in my FT980, in GEN mode, at any frenquency when I active TX in USB the current in the final state (METER I), rise uo to 10 A, even without audio in microphone and DRIVE and MONI en minimun. In LSB the current is zero, normal. Any hint to this anomaly? Tnx.... CP6CL - JOSE Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525 |
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Hi, Wald, very thanks for reply. This radio is not new, it is a gift of a friend.? Maybe one circuit is defectived. Very thanks. Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El martes, 2 de junio de 2020 03:29:13 p.?m. GMT-4, Wald N4PL via groups.io <n4pl@...> escribió:
Hello Jose, I checked this scenario on my FT-980 and it is not doing that.? I tried to key up on 14.005 and 14.5 MHz. No Ic current in any mode, on any freq. Have you had this radio since new?? If not, then you could have a CB mod for GEN TX.? They did that to get on 11m USB back in the days. 73, Wald N4PL
On Friday, May 29, 2020, 11:27:32 PM EDT, jose carlos leon via groups.io <josecarlosleon48@...> wrote:
Hi, friends, I have noted in my FT980, in GEN mode, at any frenquency when I active TX in USB the current in the final state (METER I), rise uo to 10 A, even without audio in microphone and DRIVE and MONI en minimun. In LSB the current is zero, normal. Any hint to this anomaly? Tnx.... CP6CL - JOSE Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525 |
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Hi Jose,
A good idea by Wald to check for GEN TX mods. There is a Gen folder in the Files section with some RF board pictures and info. I was looking for items to add to the Files section and found an item about FT-980 batteries. Take a look at "FT-980 Batteries". I would try starting the FT-980 with no batteries to see if the default program clears the problem. Then put fresh batteries in. 73 Roger VE7LB |
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Thanks, Roger,? I will check it. Battery on radio are new for a moment. Is only with USB at any band. (The current rise up to 10 A without any modulation on microphone. In LSB all is ok). Jose Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El miércoles, 3 de junio de 2020 02:50:46 p.?m. GMT-4, Roger VE7LB <roger_ve7lb@...> escribió:
Hi Jose, A good idea by Wald to check for GEN TX mods. There is a Gen folder in the Files section with some RF board pictures and info. I was looking for items to add to the Files section and found an item about FT-980 batteries. Take a look at "FT-980 Batteries". I would try starting the FT-980 with no batteries to see if the default program clears the problem. Then put fresh batteries in. 73 Roger VE7LB |
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Are you thinking on autooscilations)? Thanks, good hint. Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El jueves, 4 de junio de 2020 11:36:08 a.?m. GMT-4, Fred_N8YX <n8yx@...> escribió:
Put a dummy load and a frequency counter on the antenna connector. Key the rig. Is RF being generated? If so, at what frequency? 73 - Fred, N8YX |
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Jose, Fred has a good point.? It would be good to know what your rig is putting out in GEN mode.? You were saying it was drawing a significant current.? If it were generating a real USB signal, the current should be zero (actually, the idle current, with no mic audio).? It would be great if you could connect a spectrum analyzer or a frequency counter after the dummy load.? Yes, this could be self-oscillations. Let us know of your progress. 73, Wald N4PL
On Thursday, June 4, 2020, 12:02:21 PM EDT, jose carlos leon via groups.io <josecarlosleon48@...> wrote:
Are you thinking on autooscilations)? Thanks, good hint. Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El jueves, 4 de junio de 2020 11:36:08 a.?m. GMT-4, Fred_N8YX <n8yx@...> escribió:
Put a dummy load and a frequency counter on the antenna connector. Key the rig. Is RF being generated? If so, at what frequency? 73 - Fred, N8YX |
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Yes, I will use an oscilloscope to view the frequency. The current is high even without microphone, but only in USB. Thanks. Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El jueves, 4 de junio de 2020 04:28:53 p.?m. GMT-4, Wald N4PL via groups.io <n4pl@...> escribió:
Jose, Fred has a good point.? It would be good to know what your rig is putting out in GEN mode.? You were saying it was drawing a significant current.? If it were generating a real USB signal, the current should be zero (actually, the idle current, with no mic audio).? It would be great if you could connect a spectrum analyzer or a frequency counter after the dummy load.? Yes, this could be self-oscillations. Let us know of your progress. 73, Wald N4PL
On Thursday, June 4, 2020, 12:02:21 PM EDT, jose carlos leon via groups.io <josecarlosleon48@...> wrote:
Are you thinking on autooscilations)? Thanks, good hint. Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El jueves, 4 de junio de 2020 11:36:08 a.?m. GMT-4, Fred_N8YX <n8yx@...> escribió:
Put a dummy load and a frequency counter on the antenna connector. Key the rig. Is RF being generated? If so, at what frequency? 73 - Fred, N8YX |
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Hello Gang, Maybe I misunderstood the question but The came from the factory to able to just receive in GEN mode.? Yaesu and others had ways to get the 980 to transmit on GEN.? I bought a FT-980 that transmitted on GEN and I used that on 60 meters.? I had the separte channels? in memories so all I had to do was turn on the rig and hit a memory button.? Worked great until others got 60 meter (5 mhz) and could use other modes and frequencies.? Cheating on power was obvious as I heard stations on m7 80 meter half loop but several stations always got better signals than I did.? I worked 21 DXCC entities plus 41 states including KH6 and KL7. 73 dave K4JRB ? ? ? _._,_._,_ |
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Hi guys, ?I have measured the output frequency in this abnormal mode that my FT980. ?I remind you of the problem: "In the GEN mode, when the USB is activated, the current (uo to10 A) and power output of the radio are high, even without modulating the microphone. In LSB it does not happen". ?Well, I measured all frequencies at the output of the 50 ohm dummy load, both OM and many others (1.8, 3.7, 6.1, 7.1, 8.1 10.1, 12.1, 14.1, 18.1, 20.1, 21.1, 24.9, 26.1, 28.5 and 29.8 MHz ). In all of them, the output frequency is the same as that shown on the display. ?In LSB mode there is no current and output. In AM is, depending
on the position of the DRIVE control.
? Dr. José Carlos León Ortega UDI- Universidad para el Desarrollo y la Innovación Tel. (591 3) 3422525
El jueves, 4 de junio de 2020 05:33:19 p.?m. GMT-4, Dave Thompson <thompson@...> escribió:
Hello Gang, Maybe I misunderstood the question but The came from the factory to able to just receive in GEN mode.? Yaesu and others had ways to get the 980 to transmit on GEN.? I bought a FT-980 that transmitted on GEN and I used that on 60 meters.? I had the separte channels? in memories so all I had to do was turn on the rig and hit a memory button.? Worked great until others got 60 meter (5 mhz) and could use other modes and frequencies.? Cheating on power was obvious as I heard stations on m7 80 meter half loop but several stations always got better signals than I did.? I worked 21 DXCC entities plus 41 states including KH6 and KL7. 73 dave K4JRB ? ? ?
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I did a little research in the Technical Supplement. Short of a circuit malfunction or (unknown) modification, there should be no way that Ham/Gen VFO selection logic should unbalance the various mixers, the Balanced Modulator or alter the BFO frequency.
So, a couple of questions: Did the radio ever work properly? If so, what happened immediately prior to the failure? One thing I would check is the setting of TC4001 (another member hinted about this). Consult the Technical Supplement for the procedure and the frequency to which it is set. The symptoms are characteristic of a malfunctioning Balanced Modulator; that is, one whose Carrier Null point isn't set properly. Since everything in this rig is tied to a couple of reference oscillators and logically derived from them, we need to figure out if it's an adjustment issue or a logic fault. 73 - Fred, N8YX |
Very thanks, Fred, unfortunately I don't know the history of the radio, it was a gift.
Now, if the problem is due of bad adjustem in a VCO or oscillator, the problem should be also in HAM mode, not only in GEN mode.
I repeat: in HAM everything is normal, but in GEN in USB mode, the current is high even without audio on the microphone. In LSB it is normal.
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Fred, No FT-980 ever had GEN TX unless it was modified by the owner.? I did have one years ago that Phil K4DPK modified? and he did not use the risky Yaesu recommended mod.? 73 Dave K4JRB -----Original Message----- |
开云体育have 2 980s from 1982,1983 shortly after purchase, yaesu contacted original owners and offered a general transmit board. they asked 9.95$ to cover handling. easy installation was drop in, solder couple pins into already existing board, connect couple wires. said you needed to use an external low pass filter if ever using the gen for new bands. they had a separate set of wider band pass filter for gen coverage and they would not be adequate for fcc supression. have the directions somewhere. both still operate properly after all these years there was a hodge podge mod put together by the ft user group people, but very complicated. probably still have in my ft newsletters from back then bob donchez wb3hyb On Jun 6, 2020, at 10:21 AM, Dave Thompson <thompson@...> wrote:
? Fred, No FT-980 ever had GEN TX unless it was modified by the owner.? I did have one years ago that Phil K4DPK modified? and he did not use the risky Yaesu recommended mod.? 73 Dave K4JRB -----Original Message----- |
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Back into this thread after a few days hiatus spent playing with non-ham-radio things.
Since the transceiver's history is unknown, the first rule of troubleshooting comes into play: "Assume nothing". Set the two reference oscillators per the Technical Manual. Then examine the behavior when on the Gen VFO...did it change? In terms of modifications, there are three potential classes here: Those which Yaesu published or offered (including the General Coverage RF Unit module), those which the Fox Tango Club and affiliated persons published...and those which never were documented, were partially finished, etc. At some point in the past, the transceiver might have had a homebrewed/undocumented modification designed to accomplish a specific objective other than enabling the Gen VFO to transmit. Going back to the Balanced Modulator and other mixer circuits: After verifying reference oscillator settings, the next thing needed in this area is to confirm proper operation at the circuit on both Ham and Gen VFOs when in USB and LSB. This will give potential insight for the next part of the process. With an accurate frequency counter, look at the output of Q4007 (2SC535A) or the input of Q3009 (MC1496P; the Balanced Modulator). Do so in USB and LSB when in Ham and Gen VFO mode. Referring to the data in the Technical Supplement, one should see signals of 8984.5 or 8990.5KHz (mode dependent) at these points. What is seen here? 73 - Fred, N8YX |
N4PL
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