ICOM VHF Question/Problem

S

Sea Bitt

Member
exMember
Joined
Jul 29, 2005
RO Number
18475
Messages
174
I have an ICOM M402 with a problem when transmitting. Seems when I try to transmit the unit will beep and display all characters on the display and stop transmitting. Wondering if anyone else had the same problem?

More information, I checked the SWR and it is OK so antenna seems to be OK. Receive is OK, as is low power setting which by the meter is about a 1 watt. Seems to be a high power transmit problem and once in awhile it will work for a few seconds. Could be a heat related problem. I called ICOM and for $50 they will give me an estimate to fix with a hourly rate of $90. So their recommendation is to “buy new" and forget trying to get it fixed. Sound familiar? This unit is also one with the remote microphone capability which I installed so I can use on fly bridge or cabin. I found out you can't use the mic or cables from the M402 for any of the new radios so would need to rewire everything. This unit is DSC capable, which leads to another issue. How do you un-program MMSI code in the unit?

Has there been reports of emergency call from a radio with the wrong MMSI numbers? Are you libel for not removing the code? So what do you do with a mostly receive only radio (low power only)? Car, home, junk pile, sell it or just trash it?
 
Can you find someone selling another M402? I had one of those and liked it, but the problem you're explaining sounds like a power board issue or not enough power available when transmitting. If it were a portable, I'd say the battery was dead/not charged. Check to be sure you don't have an issue with a ground.

As for the MMSI, just program a new number over it, like all zeros or something. That's what I did when I sold mine. I didn't want a radio out there with my MMSI code in it. You can program it up to like 5 times as a consumer. After that, you need to have Icom do it.

You can get the manual here, and it has directions on programming the MMSI (page 11):
http://www.icomamerica.com/en/downloads/Default.aspx?Category=99
 
It is very likely that you have a bad power connection outside of the radio. While on low power or receiving, the current draw is modest but when you try to transmit at 25 watts, the current causes the voltage to the radio to drop. The radio reboots itself when you stop transmitting and displays the normal "every thing lit up" test display.

Go through and wiggle the wiring to the radio and spray it with WD40 or better.
 
sounds as if you are getting RF in to the radio...perhaps a chafed cable, missing ground or defective antenna connector. You might try hooking it up to a separate, free standing antenna...that would prove whether it is the radio itself or something in your installation.
 
The Icom 402's MMSI number can only be programmed twice so if you decide to get rid of it, you'll only have one opportunity to overwrite your MMSI numbers with nine zeros.

I'd agree with rbmitchell above and suggest you carefully verify the DC wiring to your radio. No twisted wire splices and both positive and negative leads to a known good power source capable of providing at least 15 amps DC. You can verify by measuring the voltage at the power leads during high power transmit. If the voltage sags, you've found the problem.

If you can't troubleshoot the problem, EBay has a couple of M402s for sale, one new-in-box for, I think, $129.00.

Bill
 
Problem:
I have an ICOM M402 with a problem when transmitting. Seems when I try to transmit the unit will beep and display all characters on the display and stop transmitting. Wondering if anyone else had the same problem?

Suggested Solution by rbmitchell:
It is very likely that you have a bad power connection outside of the radio. While on low power or receiving, the current draw is modest but when you try to transmit at 25 watts, the current causes the voltage to the radio to drop. The radio reboots itself when you stop transmitting and displays the normal "everything lit up" test display.
Rbmitchell had the correct answer. It was a bad barrel connected in the power line. Replaced cord and all is well. Thank you and Boat Ed for another solution and saving me money which pays for the Boater Ed Subscription.
Thanks to all.
Bruce
 
You must log in or register to reply here.
Back
Top