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[Articles Home]  [Add Article]  

Icom IC7000 Tuner Connector Warning!

Bob Lewis (AA4PB) on August 22, 2006
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IC-7000 & Tuner Warning!

I have had to make a change to my Icom/SGC tuner interface circuit to make it function properly with the new IC-7000 radio. It appears that Icom internally shares one of the tuner connections with its temperature sensor circuit on this radio. You must be very careful what you connect to the IC-7000 tuner connector. Some of the little circuits that we are used to plugging into the Icom tuner connector in order to make the TUNE button work can upset the temperature sensor circuit. In some cases this may prevent the fan and over temperature warning from coming on, resulting in “cooking” the finals in the radio!!!

The relevant tuner connection is pin-1 (TKEY). This pin can be pulled to ground via an open collector circuit during tune operations (this is what the Icom AH-4 tuner does). You must not have any applied external voltage or load on this pin during normal radio operation or you risk damage to the radio.

Bob Lewis (AA4PB)

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Icom IC7000 Tuner Connector Warning!  
by AB2MH on August 22, 2006 Mail this to a friend!
Hmm. My 7000 cooked two sets of finals. It's now on its way back to Bellevue, WA.

I have a N2VZ Turbo Tuner attached to mine.

Does anyone know if the N2VZ Turbo Tuner will cause this?
 
Icom IC7000 Tuner Connector Warning!  
by KI4NX on August 22, 2006 Mail this to a friend!
There's a good website to check on the 7000 add-ons. It's K0BG's site: www.k0bg.com it has the information about the tuners and that sensor connection on pin one.
 
RE: Icom IC7000 Tuner Connector Warning!  
by N3OX on August 22, 2006 Mail this to a friend!
AB2MH: Probably. Looks like you found your problem, from AA4PB's other post in the Elmers forum it seems that few of those devices are okay, only Icom tuners and maybe one or two others.

73,
Dan
 
RE: Icom IC7000 Tuner Connector Warning!  
by AB2MH on August 22, 2006 Mail this to a friend!
Where do you see this on Alan's website?

The only thing I see is this, under "miniature rigs":

>>>>Here is an important caveat about the IC-7000. The port on the rear apron of the IC-7000 designed to interface with the AH-4 auto coupler is configured differently than the IC-706 series. Pin 1 (TKEY) input is shared internally with the temperature control circuitry. This pin MUST be left floating. If it isn't, the fan may not come on as required, which can lead to failure of the final transistors!

Devices used to mimic the AH-4, and trick the IC-706 into transmitting 10 watts of carrier are not compatible with the IC-7000. This includes the suggested circuitry from SGC, at least one of the older model screwdriver controllers, and most small tuner modules. The only US made one known to work correctly is from Better RF, and designed specifically for the IC-7000. Their older IC-706 model is not compatible. There is also an Australian one designed by Owen Duffy, VK1OD, which is compatible. If you are using one of Bob Lewis' (AA4PB) Ham-Kit interfaces, remove R1 (33k) entirely, as it is not needed.<<<<

I've noticed that when tuning, the temp gauge would go down to almost 1/4 of where it was before. But when receiving/transmitting it stays the same as if no tuner were connected.

So I suspect my 7000's final failures had a different cause.
 
RE: Icom IC7000 Tuner Connector Warning!  
by AB2MH on August 22, 2006 Mail this to a friend!
N3OX wrote:

> AB2MH: Probably. Looks like you found your problem,
> from AA4PB's other post in the Elmers forum it
> seems that few of those devices are okay, only Icom
> tuners and maybe one or two others.
> 73,
> Dan

Maybe, but I have used the rig extensively before for two months with the Turbo Tuner and have had no problems whatsoever. Also, when the finals failed, the rig was no hotter than it was during normal operation. In fact the last failure wasn't after any significant TX time at all and the rig wasn't even warm.

I did email N2VZ but have gotten no response on this.
 
RE: Icom IC7000 Tuner Connector Warning!  
by AE7Q on August 22, 2006 Mail this to a friend!
With previous Icom radios, some devices (eg, the MFJ-1925i2) that connected to the 4-pin tuner port, simply connected pins 1 (KEY) and 2 (START). If you do that on the IC-7000, you end up providing an UNWANTED voltage on pin 1, and the IC-7000 will show a (false) inflated temperature, and the fan will run.

If you DO NOT connect pins 1 and 2 together, OR replace the connection with a diode in the proper orientation (if such is required by the external device), the problem does not occur.

For more information, see http://home.comcast.net/~hamlakemn/ah4/ah4.htm

Also, the inference that pin 1 has a different function than on previous Icom radios, and that this function has something to do with the temperature sensing circuitry, is incorrect.

When you feed additional voltage into a circuit that is not designed for it, it can raise the supply voltages in various UNRELATED circuits throughout portions of the radio that share the same voltage supply. Definitely NOT a good idea.
 
RE: Icom IC7000 Tuner Connector Warning!  
by AA4PB on August 22, 2006 Mail this to a friend!
Since we don't have a schematic for the IC-7000 we can't tell for certain how the circuit on that pin works or exactly what is going on. I do know that putting a pull up resistor on the TKEY pin causes the fan to run and that changing the value of that resistor will change the speed of the fan. Obviously it is related to the temperature circuit in some manner, intentional or not. A number of people using various non-icom tune modules have reported failure of the output transistors. Is it related? I don't know but I would sure check out the operation of the radio to be sure the fan works correctly with a device connected to the tuner port.

 
RE: Icom IC7000 Tuner Connector Warning!  
by AE7Q on August 22, 2006 Mail this to a friend!
"Since we don't have a schematic for the IC-7000 we can't tell for certain how the circuit on that pin works or exactly what is going on."

Yes we do. The IC-7000 service manual ($32) includes the schematics; see page 11-9 (logic board). Applying a voltage greater than +3vDC to the KEY pin will (through only a diode) be applied DIRECTLY to the +3vDC power line in the radio.
 
RE: Icom IC7000 Tuner Connector Warning!  
by K0BG on August 22, 2006 Mail this to a friend!
There are two problems associated with after-market "tuner modules".

One is a hard connection (short) between pins 1 and 2 (TKEY and TSTART respectfully), then any resistor (even a large value one) paralleled with a cap (1000 uF) to pin 3 (nominal supply voltage). The reason is, this places the nominal supply voltage on a CPU pin designed for 5 vdc. While this worked with the 706 (apparently), it doesn't work with the 7000.

To wit (IC-7000), if the resistor value is low (10K or so), the fan runs full speed. As the value increases, the fans slows. If the value is over 33K or so (depending on the internal temperature), the fan stops. But.... the temperature sense circuitry is swamped by the value of the resistor. It appears (based on trial and error) that this causes the fan to come on too late for proper cooling.

AB2MH notwithstanding, several other amateurs have reported final failures in their IC-7000s. Further investigation has revealed that every single one I have corresponded with had been using either some sort of tuning device that tricked the transceiver to output a 10 W carrier, or was using one of the various after-market screwdriver antenna controllers.

To be fair about this, some after-market tuner emulators either use a PIC exactly emulating the AH-4 (Owen Duffy, VK1OD), or use the CI-V port (Better RF for the 7000, not their original 706 unit!). These, along with some screwdriver controllers that use one of these interconnections scenarios are safe to use.

However, there are a bunch of legacy devices that are not compatible, and most assuredly will cause the finals to fail.

If you want to be safe, here is a circuit that will work with either radio, and in fact ANY Icom with an AH-4 port: If pin 2 (TSTART) and pin 3 (nominal supply voltage) are bridged with a 100K resistor (which tricks the Icom into thinking an AH-4 is connected), then a short (or an open collector is closed) is applied between pin 1 (TKEY) and pin 4 (ground), will cause the transceiver to transmit with a 10 watt CW carrier. As K5LXP has suggested on his web site, this action can be instigated with a simple relay control driven by the DC applied to a screwdriver's motor.

Two final comments. First, DO NOT ASSUME what you have been safely using with your 706 is fully compatible with your new 7000. Chances are, it is not.

Lastly, every single Icom transceiver has a slightly different implementation of the AH-4 interface. Just because your specific AH-4 emulating interface works on an Icom 706, does not mean it will work successfully with any other Icom transceiver. This is IN DEFFERENCE to advertised hype! In short, when in doubt, leave it out!

Alan, KBG
www.k0bg.com
 
Icom IC7000 Tuner Connector Warning!  
by SWANMAN on August 22, 2006 Mail this to a friend!
Use Icom tuners (AT-180) and you'll be fine!
 
RE: Icom IC7000 Tuner Connector Warning!  
by AB2MH on August 23, 2006 Mail this to a friend!
>>>>>To be fair about this, some after-market tuner emulators either use a PIC exactly emulating the AH-4 (Owen Duffy, VK1OD), or use the CI-V port (Better RF for the 7000, not their original 706 unit!). These, along with some screwdriver controllers that use one of these interconnections scenarios are safe to use.<<<<<<<


The Turbo Tuner uses CI-V.
 
RE: Icom IC7000 Tuner Connector Warning!  
by AB2MH on August 23, 2006 Mail this to a friend!
Swanman wrote:

> Use Icom tuners (AT-180) and you'll be fine!

Unfortunately the AT-180 does not control a screwdriver antenna.
 
Icom IC7000 Tuner Connector Warning!  
by PE1JLJ on August 23, 2006 Mail this to a friend!
I am using the IC7K, wth an AT100Pro and the LDG IC2/AC-1 6" CABLE.

This combination doesn't seem to have any side effects on the fan; it starts during transmit, it stops without problems.

I haven't seen the temp indication go in the red area at all, even while being prolonged used on 6m FM.

YMMV though.

There are modifications that will let the fan run 24x7; if you look around you can find the service manual easily as well as the mods for the fan, TX extensions etc.

I found them within minutes ;-)
 
RE: Icom IC7000 Tuner Connector Warning!  
by K0BG on August 23, 2006 Mail this to a friend!
There is another issue with the tuner port, and although it has been mentioned previously, it bears repeating.

A lot of after-market devices, including some screwdriver controllers, antenna tuners, and digital interfaces, use the tuner port (or Accessory socket) for power. Icom states you can draw power up to one amp from pin 8 of the accessory port. Although no specs are published about the current draw from pin 3 of the tuner port, most folks assume up to one amp is okay as this is what the AH-4 draws when it's tuning.

Both of these ports are fused (4 amps for the 706, and 5 for the 7000), and both are switched on and off by a switching transistor. If you short either of these ports to ground, there are three failure scenarios.

First, the fuse will blow which doesn't happen often. Secondly, the switching transistor will fail (usually open). And lastly, and most likely, the circuit board trace will melt. The latter two failures are costly ones to repair.

Further, the voltage drop across these ports with a one amp load imposed on them, is just over 1 volt less than the supply voltage. While this might be okay for short durations like the tuning cycle of an AH-4 or other tuner using the port for power, long term draw means that 13 watts or so of heat is being absorbed by the radio's circuitry.

I'm of the opinion that if you need the radio to supply switched power to an ancillary device, that you use a properly buffered relay to do the task.

Alan, KBG
www.k0bg.com
 
RE: Icom IC7000 Tuner Connector Warning!  
by WA2JJH on August 23, 2006 Mail this to a friend!
It seems every new "Swiss Army DC-daylight" rigs do not have decent designed finals. It is always a good idea to run reduced power at first with a new tuner.

The FT100D had major final problems. It was not until the rig undergone many revisions, that it could be used normally.

Even still, I was told to run 2/3 power on UHF, because the final brick really could not output 25W for long.

Heat dissipation, high current, and final shut down/pwr foldback has always been an issue with the first few production runs of these small wonders.

I waited until the FT-100D was almost out of production before I purchased one.

I am sure ICOM is all too aware of their new mobile gem. Check for ICOM updates as well as the many knowledgle hams on e-ham.

It does seem that a ham first finds the problem and a cure. The company then learns from that. A revision is made The revision should be offered for free from the company if it is a major one.

The small print always says.......we reserve the right to revise without notice.

I am waiting a while before I buy the 7000. My late serial number FT-100D is still working after 4 years.
 
Icom IC7000 Tuner Connector Warning!  
by N6FM on August 23, 2006 Mail this to a friend!
Dwayne at LDG has assured me that "All LDG tuners that are capable of interfacing to an IC-7000 handles
pin 1 of the Icom interface exactly the same way as the Icom AH-4."

Mine has been working fine.


 
RE: Icom IC7000 Tuner Connector Warning!  
by K9LMM on August 23, 2006 Mail this to a friend!
My AT-7000 works fine too.

K9LMM
Larry
 
RE: Icom IC7000 Tuner Connector Warning!  
by K8RBW on August 23, 2006 Mail this to a friend!
My LDG tuners with updated firmware for the IC-7000 have been functioning fine as well. I, too, contacted Dwayne and he had informed me that there was no problem.

73
Dick
K8RBW
 
Icom IC7000 Tuner Connector Warning!  
by KK8ZZ on August 23, 2006 Mail this to a friend!
I've used the Turbo Tuner (with the recent IC-7000 firmware update) for 6 months with the Little Tarheel HF antenna (FABULOUS ANTENNA, BTW -- even on 40 and 80!) with no problems, including semi-long keydown at 10 watts when going from 6M to 80M... great combination from my viewpoint... KK8ZZ Solon, Ohio
 
Icom IC7000 Tuner Connector Warning!  
by W1YW on August 24, 2006 Mail this to a friend!
Thanks to K0BG for the clarity.

The IC-7000 is rapidly becoming (perhaps) the most popular, new HF rig. And this sort of info is critical.

73,
Chip W1YW
 
RE: Icom IC7000 Tuner Connector Warning!  
by N1DL on August 24, 2006 Mail this to a friend!
I am using the IC-7000 and N2VZ Turbotuner daily without problems. 73 de N1DL
 
RE: Icom IC7000 Tuner Connector Warning!  
by W5JON on August 24, 2006 Mail this to a friend!
ICOM IC-7000, Turbo Tuner, Little Tarheel, 6 Months, absolutely NO problems. 73, John W5JON
 
RE: Icom IC7000 Tuner Connector Warning!  
by W5TD on August 24, 2006 Mail this to a friend!
Why doesn't the 7000 just leave the fan on all the time, as the Icom 706 original did? A constant running fan means a cooler radio, which means a radio that will last longer also.

73s John W5TD
 
RE: Icom IC7000 Tuner Connector Warning!  
by WA2JJH on August 24, 2006 Mail this to a friend!
The constant flowing fan was the fix for the ft-100D.
Problem is current consumption goes up. So those that had dreams of hours of low power QRP operation are out of luck.

One size never fits all. Seems that the K2 or some TEN-TECs are the way to go for portable batt. apps.

Perhaps ICOM wanted low current draw on RX on the 7K. Also mobile rigs do not hsve much space for a good heat sink.

 
RE: Icom IC7000 Tuner Connector Warning!  
by AD5X on August 25, 2006 Mail this to a friend!
I have the MFJ-929 auto-tuner (great tuner, by the way) with the MFJ-5114I transceiver interface cable connected to my IC-7000. I spent a lot of time last night looking at fan operation and temperature indication both with and without the tuner connected. Testing was done by doing key-down tests of the IC-7000 (into a dummy load of course) and recording the temperature change versus time (as best I could looking at that little bargraph on the IC-7000), as well as observing fan operation. I started without the tuner connected. After testing, I turned off the IC-7000 for about an hour so it started at the same temperature when I began tests again using the MFJ-929. Anyway, I saw no differences in temperature vs time, or fan operation with or without the tuner connected.

I also have an MFJ-994B that I'll test later today and report on. I don't expect any problems, as the MFJ-994B uses an open collector transistor only on the KEY input to the IC-7000.

Phil - AD5X
 
RE: Icom IC7000 Tuner Connector Warning!  
by KQ4KK on August 25, 2006 Mail this to a friend!
OK, so which after market tuner does this so called damage. All I see is lots of posts that say MY aftermarkettunerdoesnodamage.

Does any?

I also have a 7000TurboTunerLittleTarheal combo..

thanks,
Kent
KQ4KK
 
RE: Icom IC7000 Tuner Connector Warning!  
by AD5X on August 25, 2006 Mail this to a friend!
I've verified that the MFJ-994B tuner causes no problem with the IC-7000. This also applies to the MFJ-994, MFJ-993, and MFJ-993B as these all have the same tune control output (just an open collector transistor - no pullup resistor).

Phil - AD5X
 
RE: Icom IC7000 Tuner Connector Warning!  
by N4ZKF on August 26, 2006 Mail this to a friend!
I don't know. I tried to by a N2VZ tuner but he won't answer the phone or return a voicemail.

Does anyone else like theirs?
 
Icom IC7000 Tuner Connector Warning!  
by W8QT on August 26, 2006 Mail this to a friend!
The BetterRF Co.'s 7000 TUNE Control is OK. They use an open collector transistor to pull the TKEY line down.
 
Icom IC7000 Tuner Connector Warning!  
by K2UBG on August 27, 2006 Mail this to a friend!
The IC-7000 @ K2UGB mobile is on it's second set of finals. I write to say that I got the Turbotuner from N2VZ shortly after getting the 7k back from Icom(around 6-20-06) and have used it heavily ever since. No problems whatsoever and I would seriouly doubt there is any way that the turbotuner would cause a problem. Bill's device is a class act that works. Period. I have done daily, constant hf mobile for days on end and no probs.

73's and talk on your radio

John/K2UBG
 
RE: Icom IC7000 Tuner Connector Warning!  
by K5MDM on August 29, 2006 Mail this to a friend!
I was about to hook my IC 7000 to the antenna boss II but you guy have me confused, will it work ok? thanks murray please send a personal email to : radioranch@qth.com
 
RE: Icom IC7000 Tuner Connector Warning!  
by N4ZKF on September 6, 2006 Mail this to a friend!
I'm glad to hear that. I just ordered an N2VZ tuner for my 7000 yesterday. Ant is a Hi-Sierra Sidekick.

Anyone want to buy an I-box that came with it?
It doesn't work with the 7000, just the 706.

73 Dave
 
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