Tune button
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MARCO EVANGELISTA
Hello,
my 7000 is connected to the radio port of a MFJ-993B tuner. Unfortunately, the tune button on the 7000 does not trigger the low power keying of the transmitter. The TUNE message on the display lights up for a moment but then goes out immediatly afterwards. Note that the 993B tunes up well when I manually set low power and RTTY mode and push the PTT. I need your help! Thank you. Marco IU8HXM
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Paul Hansen
The 933B by itself is only going to sense RF. You won’t have control of it without the MFJ-5123I interface cable. What you are seeing is normal without the interface cable.
Thank you,
Paul W. Hansen, W6XA Amateur Radio Service 2134 Carthage Road Tucker, GA 30084 (864) 222-3539 office www.amateurradioservice.com
From: ic7000@groups.io [mailto:ic7000@groups.io] On Behalf Of MARCO EVANGELISTA
Sent: September 13, 2018 09:22 To: ic7000@groups.io Subject: [ic7000] Tune button
Hello,
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Hi Paul,
thank you for your answer. My 7000 is connected to the radio interface of the 993B using an original MFJ-5123I cable. Please also note that when I push the tune button on the 7000, the "Reverse" needle of the SWR meter of 993B has a pronounced forward dip and the 993B emits a tone. Immediately afterwards, the needle goes back to the initial position. No power from the IC-7000. The needle also dips when I change band. Best regards, Marco IU8HXM
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James Johnston <jimthej@...>
I have the same setup. When tuning stops, it is usually caused by the #1 wire breaking at the molex connector. If you have a tool for removing molex pins, you can solder in a jumper
toggle quoted messageShow quoted text
Since mine is a travel rig, I pack a spare cable. Jim Johnston
On Sep 13, 2018, at 13:48, MARCO EVANGELISTA <marcoevang@...> wrote:
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Norm Stewart
Assuming you have the 993 interface cable in the 7k 4 pin tuner
port, there does seem to be a problem with some radios - my 993
tuner worked fine with a 706, but the same cable did not work with
the 706MKIIg or the 7000. I assume that the start line is not
being pulled low enough by the radio to trigger the tuning. I put
an external push button to momentarily ground the start line, and
all works as expected with both of the newer radios. Norm w6nim On 9/13/2018 2:22 AM, MARCO EVANGELISTA
wrote:
Hello, -- Sent from my antique Win7 desktop
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Hello,
I have noticed that under particular circumstances, the tune button works as expected. After many trials, I have discovered the following sequence to have that button working: - Power up the 993B - power up the 7000. At this stage the Tune button does not work. When pushed, the red TUNE lamp on the display lights up and immediately afterwards it lights down. The transmitter is not keyed. 1) Make a tuning cycle by setting low power in rtty mode and pushing the PTT 2) Power down the IC-7000 3) Power up the IC-7000. Now the Tune button works! I really wonder what the problem is, and if the issue concerns the 7000 or the 993B. Any help will be much appreciated. 73 Marco IU8HXM
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I am guessing here. Icom changed the PTT circuit at some point. The signal from the tuner to the radio needs to be a ground. In the past, it was a +12V.
If you are using an older design tuner, it may place a 12V on the tune command lead. This has two effects – it may or may not cause the radio to start a tuning cycle, and the radio will report an over-temperature condition. This is because the radio has +8Vdc pull-up on that line that is also part of the thermocouple and by inserting 12Vdc the radio thinks it is running hot.
Icom tuners, and the IT-100 from LDG, correctly place a ground on that lead. Others may not. If your MFJ has an option to place a low/ground instead of a high/12Vdc on the control lead from the tuner to the radio, the whole setup may work better.
73,
Kevin N5KRG
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Marco, The 7K requires a voltage on pin 2 (Start) of the Tuner port when it is powered up to recognize that there is an AH-4 compatible tuner connected. In the 993B tuner, the voltage that goes to that pin comes from a PIC CPU port called WAKEUP. It sounds like the WAKEUP signal (which is used as a pullup voltage to several circuits) is not driven high by the tuner until you go through the sequence you mentioned that works. When you power cycle the 7K the second time, it then sees pin 2 as "high" and works normally. Anything you do to wake up the tuner before powering up the 7K should make it work.
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Hi Steve,
thank you very much. I'll do as you say. 73 Marco, IU8HXM
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You might check the voltage on Tuner port pin 2 to ground (pin 4 or chassis) after you first power up the tuner and radio and then after "waking up" the tuner and power cycling the radio to verify that is the problem.
Steve, W3AHL
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Hi Steve,
I have done a few voltage measurements on pin 1 and pin 2 (negative on chassis) under various conditions: A) 993B on and 7000 off, before waking up Pin 1: 0,03 V, Pin 2: 1,43 V B) 993B on and 7000 on, before waking up Pin 1: 0,02 V, Pin 2: 4,52 V C) 993B on and 7000 on during "tune" button keypress, before waking up (tune button does not work) No change with respect to condition B) D) 993B on and 7000 on, after manual tuning cycle (tuning OK, but tune button is not yet working) Pin 1: 3,03 V, Pin 2: 4,52 V E) 993B on and 7000 off, after manual tuning cycle Pin 1: 0,03 V, Pin 2: 1,46 V , i.e. almost same as condition A) F) 993B on and 7000 on, after waking up Pin 1: 3,01 V, Pin 2: 4,63 V, almost same as D) F) 993B on and 7000 on, during "tune" button keypress, after waking up (tune button works as expected) Pin 1: 0 V, Pin 2: 3,04 V What changes before and after wakup is that before Pin 1 is at 0V, whilst after it is at 3V and it goes to 0V during tune button keypress. Turning the 7000 only off and then on leaves the system in the "after wakeup" condition (tune button works). Turning both the 7000 and 993B off, then 993B on and then 7000 on leaves the system in the "before wakeup condition" (tune button does not work). Is the fault caused by the 993B or by the 7000 or by both? Thank you. 73 Marco, IU8HXM
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Marco,
To determine if the tuner is pulling pin 1 low in condition B, disconnect the tuner interface cable at the radio's tuner port and measure Tuner port pin 1 to ground. It should be 3 VDC. If so, then the 993B tuner is pulling that line low when it shouldn't. Stevek W3AHL
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MARCO EVANGELISTA
Steve,
under the "before wakeup" condition, when the cable is connected to the 993B, but disconnected from the IC-7000, Pin 1 is at 0V. Marco IU8HXM
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I'm traveling until about October 3 and don't have access to my 7K's nor test equipment. Will try to look into it more when I get home. Meanwhile contact MFJ support.
Steve, W3AHL
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