As an FYI to all here, this is what I wrote yesterday, in the other thread ("sticky")....and this was before I had any of the above additional info....
The below may be of help to others...
More later, when I have time....gotta' take my Mom to another appt...
~~~~~~~~~~~~~
Steve,
Sorry I missed this post....I don't check this "sticky" often....(next time, please start a new thread with any tech questions/troubleshooting issues, and someone is sure to help you out quickly...)
As for the specifics....
Quote:
Originally Posted by TMT2
troubled by a problem I have and don't know how to troubleshoot it if you'd be willing to advise
My ICOM 802 is showing "THRU" consistently on the screen vice "TUNE." I have an AT-140 auto-tuner and a 35" backstay antenna set up. Can you advise mo on how to troubleshoot this and get back in the "TUNE" range?
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Steve, it sounds like the M-802 is not configured for the AT-140; or AT-140 is not connected and/or the connection has failed; or (fairly unlikely) the AT-140 has failed....
Steve, you didn't say if this is a new problem, or has it always been this way??? (assuming it is a NEW problem)
Nor did you say whether or not you are receiving anything on the M-802??
(assuming you ARE receiving something, but cannot transmit much due to lack of AT-140 functionality)
So, I'll need to go over things one-step-at-a-time....
1) The M-802 display should flash "TUNE" (along the top line of the display, just to the left-of-center of the display) when you press the TUNE button (top button, just to the right of the display)....
If the M-802 display is showing "THRU" at this location, when you press the TUNE button, then the AT-140 is not getting the tune signal / the M-802 is not configured for the AT-140; or the AT-140 is not connected / not connected correctly....(or that the AT-140 has failed)
2) First we need to verify that the M-802 is configured for the AT-140 (and at the same time we'll make sure you're set for "auto-tune" as well...)
a) Enter "Initial Set Mode"....(see page 49 of the M-802 manual)
Entering set mode
---Turn the power OFF, if the transceiver is powered On
---While pushing [MODE SET], push [POWER] to turn he power On to enter initial set mode.
b) Use Group knob to select
"Icom Tuner"
c) Use Channel knob to select "AT-140"
d) Use Group knob to select "Auto Tune"
e) Use channel knob to select "On"
The turn M-802 Off and then turn it back On....
3) Next, do the test above again....
Press TUNE button and verify what the M-802 display shows....
a) If it flashes "TUNE" and then shows "TUNE" after it has completed tuning, you are all done, and everything is now working....
b) If the display still shows "THRU", then the
wiring / connectors from the M-802 to the AT-140 may have failed, chafed, broken, come un-done", etc..
c) Please physically check the auto-tuner connector on the rear panel of the M-802's Main unit, this is a small rectangular white connector on the left side of the Main Unit's rear panel, just to the left of the ground screw, and just to the left and slightly above the Main Antenna connector.....
This connector should have 4 wires on it, and should be mated completely into the matching connector on the radio....(to remove, it pulls straight out....and to re-attach, it pushes straight in...)
Check / be sure this connector is completely seated/attached....and that all 4 wires are well attached to the captive pins of the connector....(this is the only part of the M-802 that is fragile and I don't like it at all....but, it is what it is...)
If these connections prove to be good....then try the test again, press the TUNE button and verify what the M-802's display shows.....if it flashes "TUNE" while tuning and then shows "TUNE" afterward, you're done, and all is working well....
If it still shows "THRU". proceed to next step...
d) The AT-140 has two short "pig-tails" of wire coming out if it....one is the coaxial cable, and one is the tuner power and control wires....
The plugs that connects the tuner power and control wires may be a problem here...
Physically inspect these plugs, just like you did with the tuner control
plug on the rear of the M-802 itself....verify that they are mated completely and that all 4 wires are seated in their captive pins correctly....(also verify that there is no
corrosion on these connections.....shouldn't be any if proper
installation procedures were followed, but 'ya never know...)
If these connections prove to be good....then try the test again, press the TUNE button and verify what the M-802's display shows.....if it flashes "TUNE" while tuning and then shows "TUNE" afterward, you're done, and all is working well....
If the display still shows "THRU", then proceed to the next step...
e) As I wrote above, you didn't say whether or not you are receiving anything on the M-802??
(assuming you ARE receiving something, but cannot transmit much due to lack of AT-140 functionality)
Assuming you ARE receiving okay, we can assume the coaxial cable and its connections are okay...but they might just be okay enough to allow some
reception, but fail upon application of transmit RF power....
So, please inspect the coaxial cable and both connections, to verify it is in good order....
If these connections prove to be good....then try the test again, press the TUNE button and verify what the M-802's display shows.....if it flashes "TUNE" while tuning and then shows "TUNE" afterward, you're done, and all is working well....
If the display still shows "THRU", then proceed to the next step...
f) It is possible (although unlikely) that your AT-140 itself has failed....but if you have a volt meter, you can check to see if you are actually getting proper voltage from the M-802's tuner connector, and then also check at the AT-140 end of the tuner power / control cable...
PLEASE ONLY attempt to measure these voltages, if you know exactly what you are doing....as you may short-out some of these wires and blow an internal fuse (inside the M-802)....
And, if you do NOT have any voltage on Pins 3 and 4, this is probably what has happened...
Looking at the rear, from left to right....pins 1, 2, 3 and 4....
Pin 1 = Key signal = +0.5vdc to +0.8vdc DURING TUNING ONLY
Pin 2 = Start / Thru signal output
Pin 3 = +13.6vdc
Pin 4 = Negative / Ground
If you do have proper voltages on Pins 3 and 4 (13.6vdc, or whatever your present
battery voltage is), then when you press the TUNE button, with your meter on Pin 1 and 4, you should see the .5 to .8vdc signal....
If these voltages are good...connect the plugs back up, and then try the test again, press the TUNE button and verify what the M-802's display shows.....if it flashes "TUNE" while tuning and then shows "TUNE" afterward, you're done, and all is working well....
If the display still shows "THRU", then proceed to the next step...
{If the voltages are NOT there, especially the 13.6vdc on across Pins 3 and 4, then I suspect a blown internal fuse in the M-802....
And, here you should also proceed to the next step...}
g) The next step is to call Icom
Service and tell them all that you have done, including any voltage checks, etc....
You've likely got either a blown internal fuse (step "f" above) or a defective / faulty AT-140....
In either case, Icom
service will be able to help you out....
Note, you CAN change the fuse yourself IF you know what you're doing....and if you find you need to send your AT-140 into Icom for
repair, the closest Icom
service center is in Tallahassee....
Icom
Service Center -
Florida
5046 Tennessee Capital Blvd.
Tallahassee, FL 32303
Phone: (800) 649-5783
Fax: (850) 575-0346
Icom America, Inc.
Service Department
12421 Willows Road NE
Kirkland, WA 98034
Phone: (800) 306-1380
I hope this helps...
Sorry the answer is so long....but I didn't have much info from you to
work with, so I had go through everything step-by-step....
fair winds...
John
s/v Annie Laurie