ICOM M-802 Troubleshooting (From an Excellent Sticky)

[TMT2]

John…Thanks for your reply on the "sticky" – all very helpful to an SSB “rookie” like me! Some quick answers to your questions and some details on “symptoms” I am experiencing:


Original Problem: ICOM M-802 shows continuous "THRU" versus "TUNE" on any band and TX indicator bar not showing "transmit" strength.


Some qualifiers: After reading all I could get my hands on for troubleshooting (the manual is less than adequate), my entire SSB set-up appears to have been professionally installed (this is a new to me boat). I have an ICOM M-802 with AT-140 Tuner and a 35" backstay antenna. I am not using KIS counterpoise - I have 4' copper ribbon to the keelbolts. All connections are professionally soldered, clipped, sealed and clean with sealing tape in appropriate places above and below deck.

The M-802 is configured in the set-up mode for AT-140. I have checked the physical condition of all connections from the transceiver to the AT-140 and cleaned, inspected, tightened all connections. I am not using KISS – I have a 4” copper ribbon to the keel bolts.

The “no transmit” bar problem is new…and I can receive station traffic (albeit weak) due to marina RFI. The AM signals from commercial stations are the strongest (in the marina) but I have been able to faintly hear some of the cruising nets on USB. This weekend I will take the boat out and troubleshoot from “pure water” vice being surrounded by electronic infrastructure (RFI in Marina)). I do know that I must turn off the Xantrex inverter and all of the other RFI noise-makers on the boat to get the cleanest reception (that’s when I can faintly hear the USB nets in the marina) and the M-802 is directly tied to the battery bank. My most curious concern is that I cannot hear the time tones on 2.5, 5.0, 10.0 or 20 Mhz bands. Am I correct that this needs to be my “receive” litmus test?

I performed the “tune test” you detailed in your reply to the "sticky" after verifying the AT-140 selection in setup. When I select a frequency and press “tune” – the “TUNE” indicator flashes then “THRU” appears and remains constant. I will check the auto tuner connection on the back of the transceiver this weekend – I have jiggled it but not yet removed the connector from the box to verify the pins are contacting and will do that this weekend and report back. The radio is in a cabinet (in the salon) that is not susceptible to being bumped or moved and it is bolted down to the shelf. It is a good possibility (as you mention) that a cable could have “failed”…I will check continuity and ohm out all cables this weekend as well and report back. When inspecting the AT-140 tuner cables, I have reseated/cleaned the copper ribbon connection but have not removed the “tuner control wiring” to verify pin contact (will do that this weekend too). I also cleaned the connections from the AT-140 to the backstay antenna (thru deck) and ensured that the drip loop is in place. I found no corrosion anywhere below deck except patina on the copper ribbon (expected)…all other connections with nuts/washers were clean and shiny…I will verify the tuner control and signal wiring connections with a meter soon (pin to pin/coax to coax)…re-assemble and try the “TUNE/TRU” test again.

I think I need to complete all of your continuity/physical connection instructions first before I move on to item (f) in your troubleshooting advice. I am comfortable with testing wires & pin-outs for continuity but taking readings from respective pins for signal/power measurements is a less comfortable area for me…I am not afraid of it…just diligent in wanting to know “exactly” what pin/wire needs what setting on am/ohm meter to get accurate reading to report back to an expert mentor like you. I think your instructions in the "Sticky" post are detailed enough for me to work with in my ignorance.


I really appreciate your time and detailed instruction – I know it’s hard to help when you aren’t looking at it directly. I am grateful that you expend the effort and time to help fellow cruisers in need and applaud you for the outstanding instructional products you have put out on the forum – they are simply invaluable and demonstrative! I can do this – and with your help may end up sending the “right” component to ICOM for repair if the infrastructure in the boat turns out to be sound. YES – this helps a LOT! Thanks for your patience and I will come back with another post on a separate thread to ensure you see my report and that others can learn for your excellent advice/help.

Respectfully – Steve
TMT2
Gulfstar M53 Ketch sv TAKE ME THERE!
Tampa FL