[Ccarc] icom-7000 tuner warning

[Tom Murray]

Found this on e-Ham website.

Tom Murray   KB9WSL

Icom IC7000 Tuner Connector Warning!
Bob Lewis (AA4PB) on August 22, 2006
View comments about this article!

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)

Icom IC7000 Tuner Connector Warning!  Reply
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!  Reply
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!  Reply
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!  Reply
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!  Reply
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!  Reply
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!  Reply
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!  Reply
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!  Reply
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, KØBG
www.k0bg.com

Icom IC7000 Tuner Connector Warning!  Reply

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!  Reply
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!  Reply
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!  Reply
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!  Reply

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, KØBG
www.k0bg.com

RE: Icom IC7000 Tuner Connector Warning!  Reply

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!  Reply

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!  Reply

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!  Reply
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!  Reply
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!  Reply

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