Reply
 
Thread Tools Search this Thread
 
Old 10 September 2007, 12:57   #1
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
icom M421 cutting out

When I transmit on my Icom m421 the screen goes blank, the whole radio cuts out and then a couple of seconds later comes back on (even if I hold transmit down).

I can't find any obvious dodgy connections on the way up to it and the only other thing I can think of that wouldn't need it to be sent back on warranty return would be bad contacts on the mic. Unfortunately I can't figure out how to get the mic off and I can't find the instructions! Any ideas?
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 10 September 2007, 13:12   #2
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Nos;

It sounds as if you've got an insufficient power condition. Probably due to a poor connection on the 12V supply or return, or, in the case of a new installation, could be too-small diameter wire.

When you transmit, the radio is probably trying to pull in the neighborhood of 5 to 7 amps. Sounds as if you're pulling down the supply voltage enough to kill at least the display, possibly even shut the entire radio off. It comes back on again because once the thing shuts down, it stop drawing power.

You can verify the problem by connecting it directly to the battery with an temporary power feed (use an in-line fuse if you're afraid of the direct connection; won't hurt anything.)

Luck;

jky
__________________

__________________
jyasaki is offline   Reply With Quote
Old 10 September 2007, 13:30   #3
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
That's what I thought but I can't find any evidence to support that after having my head in the console for 2 hours. (granted I need to try powering up with a direct connection).

It'll work with squelch at 0 and volume at full too-and yet won't transmit on low power.

__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 10 September 2007, 14:01   #4
Member
 
ashbypower's Avatar
 
Country: UK - England
Town: Salisbury/Poole
Boat name: Blue C
Make: XS 600
Length: 6m +
Engine: 125hp Opti
MMSI: 235082826/235909566
Join Date: Jan 2004
Posts: 1,439
Nos,
Have you checked the VSWR? some sets (don't know about the 421) will shut down if VSWR is thro' the roof.
__________________
Brian C
Harbour Sea School & APS Marine Centre
ashbypower is offline   Reply With Quote
Old 10 September 2007, 14:14   #5
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
No-it was transmitting fine up til about a few weeks ago then it started. It's still receiving OK.It hadn't been used for 3 weeks previously.

I'm not even seeing any change to the display before it cuts out either.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 10 September 2007, 14:36   #6
Member
 
Country: Other
Town: Oakley
Boat name: Zerstörer
Make: Ribcraft
Length: 5m +
Engine: Suzuki DF 140
MMSI: 235050131
Join Date: Jun 2003
Posts: 3,931
Matt,

Check all the negative wiring carefully. I know its hard because boats always seem to have tons of wiring spaghetti. Might be worth running a new earth !
__________________
http://www.xfire.com/download/
Biggles is offline   Reply With Quote
Old 11 September 2007, 04:29   #7
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,610
Batery switch?

Nos,

I had exactly that problem about a month ago after I managed to prove SRs also make good paddling pools (don't ask! ) - got salt water into my battery switch, and found a "creeping death" - started as the radio dying when I cranked the engine / transmitted, a week later the engine wouldn't even crank, and even just use of the choke button was enough to kill the VHF momentarily. 2 days later and the battery was as good as a sandbag under the seat for the amount of juice getting through the switch.

One new battery switch later and all worked fine! The moral of this story: check more than just your connections.......
__________________
9D280 is offline   Reply With Quote
Old 11 September 2007, 05:58   #8
Member
 
ashbypower's Avatar
 
Country: UK - England
Town: Salisbury/Poole
Boat name: Blue C
Make: XS 600
Length: 6m +
Engine: 125hp Opti
MMSI: 235082826/235909566
Join Date: Jan 2004
Posts: 1,439
Quote:
Originally Posted by Nos4r2 View Post
No-it was transmitting fine up til about a few weeks ago then it started. It's still receiving OK.It hadn't been used for 3 weeks previously.

I'm not even seeing any change to the display before it cuts out either.
Matt in that case I'm the rest check for a high resistance joint, and switch contacts, before ripping out the TX.
__________________
Brian C
Harbour Sea School & APS Marine Centre
ashbypower is offline   Reply With Quote
Old 11 September 2007, 14:19   #9
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Thats what I'm hoping it is too. I'll have another look through it all before the end of the week and see what I can find.
What seemed unusual though is the cutting out and coming back on while the tx button is held down-ie when it comes back on I've still got the TX button held.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 11 September 2007, 14:26   #10
Member
 
ashbypower's Avatar
 
Country: UK - England
Town: Salisbury/Poole
Boat name: Blue C
Make: XS 600
Length: 6m +
Engine: 125hp Opti
MMSI: 235082826/235909566
Join Date: Jan 2004
Posts: 1,439
Matt, have you got a multimeter? if so try taking a voltage measurement at the closest feed point to th VHF and see if the voltage collapses when you TX.
__________________

__________________
Brian C
Harbour Sea School & APS Marine Centre
ashbypower is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 03:31.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.