Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Icom IC-7000 VHF/UHF Transceiver "Adjustment Mode"

Hi,

I recently bought an Icom IC-7000 transceiver from the estate of a
"silent key". The UHF power output, although the radio is set to
"100 percent power" (all bands), puts out about 50 percent on the
UHF band. UHF watt meter indicates around 18 watts when it
should be 35 watts. Note: Other bands are just fine at 100 percent.

I downloaded the service manual from www.mods.dk and followed
the procedure to enter the "Adjustment" mode. However, I can not
change any settings beyond the "Total Gain (430)! My intention
was to increase the "100 percent" value, which is beyond the "Total Gain"
adjustments, to see if the power goes up. Note: I am using a proper dummy
load.

I couldn't find in the service manual or service manual addendum
any information regarding this issue.

By any chance, did you encounter the same situation?

Thank You in Advance, John N3AOF

PS, Remove "ine" from my email address


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Default Icom IC-7000 VHF/UHF Transceiver "Adjustment Mode"

Do a web search for iCom. They will answer your questions...

I would suspect a problem in the final output, or in the drivers. If
you have the service manual, follow through by verifying the supply
voltages to the final and modulator sections. Also, verify the
carrier amplitude.

I don't know the unit, but also check in the user book to see if there
are any settings for reduced power output.

I am assuming that all the standard procedures of antenna match and
etc has been done...


Jerry G.



On Oct 13, 1:10*pm, wrote:
Hi,

* * *I recently bought an Icom IC-7000 transceiver from the estate of a
"silent key". * The UHF power output, although the radio is set to
"100 percent power" (all bands), puts out about 50 percent on the
UHF band. * UHF watt meter indicates around 18 watts when it
should be 35 watts. *Note: Other bands are just fine at 100 percent.

* * I downloaded the service manual fromwww.mods.dkand followed
the procedure to enter the "Adjustment" mode. *However, *I can not
change any settings beyond the "Total Gain (430)! * My intention
was to increase the "100 percent" value, which is beyond the "Total Gain"
adjustments, *to see if the power goes up. * Note: I am using a proper dummy
load.

* * *I couldn't find in the service manual or service manual addendum
any information regarding this issue.

* * *By any chance, did you encounter the same situation?

* * * *Thank You in Advance, *John N3AOF

PS, *Remove "ine" from my email address


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Default Icom IC-7000 VHF/UHF Transceiver "Adjustment Mode"

On Fri, 15 Oct 2010 08:37:50 -0700, Jerry G. wrote:

Do a web search for iCom. They will answer your questions...

I would suspect a problem in the final output, or in the drivers. If you
have the service manual, follow through by verifying the supply voltages
to the final and modulator sections. Also, verify the carrier
amplitude.

I don't know the unit, but also check in the user book to see if there
are any settings for reduced power output.

I am assuming that all the standard procedures of antenna match and etc
has been done...


1. Make sure the SWR on the UHF antenna is 1.5:1 or below. If ok it could
be the hybrid output device. Not knowing the 7000 I would assume that it
would have a separate output device for UHF. However I would verify the
power input to the device and its voltage and AGC circuits before deeming
it bad.



--
Live Fast, Die Young and Leave a Pretty Corpse
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Default Icom IC-7000 VHF/UHF Transceiver "Adjustment Mode"

In article ,
wrote:

I downloaded the service manual from
www.mods.dk and followed
the procedure to enter the "Adjustment" mode.


John-

If I understand, you are trying to increase power beyond 100%. My
thought is that you are getting all you can with the hardware you have.
The hardware may be defective and the computer can't compensate for that.

My problem is with frequency adjustment. When I enter the Adjustment
mode, I can set the oscillator frequency to exactly what it should be.
However, frequency returns to the previous value when I leave the
Adjustment mode. If I re-enter Adjustment mode, the oscillator
frequency goes back to the correct value, and again reverts when exiting
Adjustment mode.

Do you or anyone else know what I might be doing wrong? Is there a step
I'm missing that makes changes "take"?

Fred
K4DII
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Default Icom IC-7000 VHF/UHF Transceiver "Adjustment Mode"

On Wed, 13 Oct 2010 13:10:28 -0400, wrote:

I recently bought an Icom IC-7000 transceiver from the estate of a
"silent key". The UHF power output, although the radio is set to
"100 percent power" (all bands), puts out about 50 percent on the
UHF band. UHF watt meter indicates around 18 watts when it
should be 35 watts. Note: Other bands are just fine at 100 percent.


Easy. Q401 or something around it.

See block diagram on Page 3-5 of the service manual. The driver blob,
IC504, drives all the bands. There are 3 separate power amps.
Q301/Q302 for HF, Q501 for VHF, and Q401 for UHF. Since everything
except UHF is working, methinks everything up to and including the
driver blob is also working.

I have no idea what's wrong, but I have a guess based on experience
fixing one of these abomination. The solder connection between the
rear panel UHF connector and the PA PCB is possible broken. Anything
else would case zero power output. The fact that you have some power
output means that the output stage is probably working, but little of
the produced RF is making it to the watts guesser.

Ummm... that brings up an other problem. Make sure your wattmeter is
working, accurate, and that you do your testing into a dummy load, not
an antenna. There's nothing more frustrating that troubleshooting a
working radio only to find your test equipment at fault.

I downloaded the service manual from
www.mods.dk and followed
the procedure to enter the "Adjustment" mode. However, I can not
change any settings beyond the "Total Gain (430)! My intention
was to increase the "100 percent" value, which is beyond the "Total Gain"
adjustments, to see if the power goes up. Note: I am using a proper dummy
load.

I couldn't find in the service manual or service manual addendum
any information regarding this issue.


Some free advice on working on the IC-7000. It's one of the worst
mechanical radio nightmares I've ever had to deal with. Some hints
and warnings:

Pulling the boards are hell because the self stripping screws are only
good for perhaps a few insertions and removals before the threads are
stripped in the aluminum casting. Be VERY careful when removing and
inserting screws.

The plastic front panel on the radio section has a connector
eventually going to the control head. Good luck getting it out and
back in. Take photos of how the cable it tangled behind the panel or
you'll never get it back together. Also, take photos of how the wires
and cables are routed, as they're not obvious or easy to guess.

Removing the PA board is a mess. The driver blob, IC504 is attached
to the casting by two inaccessible screws (someone forgot to drill
clearance holes in the PA PCB). Therefore, you have to unsolder the
leads to IC504 in 5 places in order to remove the board. Lots of
other unsoldering to be done. See:
http://802.11junk.com/jeffl/Icom%20IC-7000/
http://802.11junk.com/jeffl/Icom%20IC-7000/PA-circuit-side.jpg
The circles and ovals are what needs to be removed before the PA board
can be removed. IC504 are the 5 purple circles near the top.

Notice that the driver blob is still attached to the casting after
removing the PA board:
http://802.11junk.com/jeffl/Icom%20IC-7000/Everything.jpg

Note the two (purple circle) solder points per UHF connector on the
right. That's where I guess(tm) your problem is hiding.

Also, don't get any water into the radio. The multitude of flex PCB
ribbon connectors on all the boards tend to rot quickly.

I have a mess of other non-complimentary things to say about the
mechanical design of the IC-7000, but I must admit that as long as
it's working, it sure is a nice little radio. It's just that it was
never designed to be repaired.

I have some more photos if you need them.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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