Codan 8525 problems

Submitted: Sunday, May 22, 2011 at 10:00
ThreadID: 86466 Views:3749 Replies:5 FollowUps:4
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Hi All,

We have been using a Codan 8525 (with remote head) HF radio for years. Intermittently it has failed to transmit, usually resuming operation after reseating all connections. But now it has decided to stay in no-transmit mode. All other functions seem ok, receive is fine, speaker audio is muted when the press-to-talk switch is pressed, but the tx light remains dead when it should be responding to audio modulation.

The antenna is mounted on the bullbar with heavy braided earthing to the vehicle body and also bonnet lid to body.

The 8525 tx is supposed to power down if not properly loaded, so have replaced antenna feed cable - no joy. The jumper connectors on the tapped whip are clean and the jumper is ok. My next step is probably to set up a long wire antenna (8.2m at 8022 Mhz?) so as to rule out the tapped whip.

I've been through the archive and got some good suggestions there to explore, also the Yahoo Codan site, but would welcome any further suggestions. Without comment from others I find it very easy to blindfold yourself by committing to your own invalid assumptions!

Any thoughts?

TIA

John
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Reply By: Member - Stephen L (Clare SA) - Sunday, May 22, 2011 at 11:17

Sunday, May 22, 2011 at 11:17
Good Morning John

We have the same radio and have had it since new, and a great radio it is. A good number of year ago, I was having the very same problem as you, could receive OK, but could not get a transmission out. I still have a tap antenna and checked all fitting and it all seemed OK.

Took the main box out and the remote head and sent it off to Adelaide for repairs. I received a phone call back about a week later and they said that they could not fault the unit, so can I send down the microphone. It turned out that there was a dry solder joint in the microphone, they fix the problem and has still been working faultlessly for over 10 years since the problem was fixed.

Weather this is the same problem, but take the whole unit out and take it to someone that knows their job and it could be as simple as my problem.


Regards


Stephen
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AnswerID: 455111

Follow Up By: Andrew & Jen - Sunday, May 22, 2011 at 11:44

Sunday, May 22, 2011 at 11:44
Hullo John
Before removing anything, I would suggest you get the microphone checked.
If you have a comms company handy, it might be worth just driving to them and ask for the mic to be checked. If none handy, try to borrow someone's mic and try it.
They are relatively cheap to replace.
Mine played up - dry joint - and I now keep it as a spare after someone soldered it for me.
Cheers
Andrew
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Reply By: MEMBER - Darian, SA - Sunday, May 22, 2011 at 11:29

Sunday, May 22, 2011 at 11:29
Love your last line John :-o).....how true.
Ditto to Stephen L - I'm no HF technician but my first thought in response to your description was the mike, in that the press to talk button initiates the TX mode.
AnswerID: 455112

Reply By: Member - Tony (ACT) - Sunday, May 22, 2011 at 12:16

Sunday, May 22, 2011 at 12:16
Had the same set in our 47 Troopie, and it had the same fault as yours. It was the Hand Mike at fault.

Take it out to Watts in Fyshwick, they will fix it. The other thing was the main box was full of dust and that stopped the Auto tune from working at all times when tunning.
AnswerID: 455115

Reply By: Member - John and Val - Sunday, May 22, 2011 at 15:34

Sunday, May 22, 2011 at 15:34
Thank you everyone for your thoughts. Consensus says microphone, so it's coming apart today. If that doesn't solve it, then to the local experts (Watts) tomorrow.

Cheers

John
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AnswerID: 455125

Follow Up By: Member - John and Val - Sunday, May 22, 2011 at 17:42

Sunday, May 22, 2011 at 17:42
Well, took the mic apart, all looked good, ptt switch did what it should, resoldered all soldered connections, still looked good, ptt switch still did what it should, reassembled - it works!

Hate it when they fix themselves. Strongly suspect a ptt switch with poor contacts - next time a squirt of contact cleaner before panicking.

Cheers

John
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Reply By: SelmerVI - Monday, May 23, 2011 at 14:22

Monday, May 23, 2011 at 14:22
Hi John, you can borrow my mic if you wish to test - can bring it to the next club meeting. I too have the 8525 remote head (with Selcall). Or give me a call.
Hendo
AnswerID: 455230

Follow Up By: SelmerVI - Monday, May 23, 2011 at 14:23

Monday, May 23, 2011 at 14:23
S'okay, saw you have fixed it, no need to borrow my mic! Cheers Hendo
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FollowupID: 728170

Follow Up By: Member - John and Val - Monday, May 23, 2011 at 14:33

Monday, May 23, 2011 at 14:33
Thanks Hendo. Appreciate the offer and may well call on you if it un-fixes itself again as easily as it fixed itself!

Cheers

John
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