[Icom] Weird, SEND relay on IC756PRO, again

Adam Farson [email protected]
Sat, 29 Mar 2003 23:14:29 -0800 

Hi Doug,

One could conceive of the contacts being stuck together with a thin layer of
oxidation or other impurities between them. When voltage is applied to the
coil, it will cause the contact springs to press harder against one another,
and reduce the resistance of the contact area.

As an initial check, you could try tapping the relay with a plastic
screwdriver handle. If this clears the low-resistance path in the "off"
(receive) state, the above explanation is probably valid. In any event, you
will need to replace the relay.

Good hunting! Best 73,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/
Icom FAQ site:
http://www.qsl.net/icom/


-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Doug Faunt N6TQS +1-510-655-8604
Sent: Saturday, March 29, 2003 18:33
To: [email protected]
Cc: [email protected]
Subject: Re: [Icom] Wierd, SEND relay on IC756PRO, again


Yep.  "partially welded"?  Is that possible?

73, doug

   From: Adam Farson <[email protected]>
   Date: Sat, 29 Mar 2003 17:49:15 -0800

   Hi Doug,

   Silly question: Did you disconnect the cable from the SEND jack and
measure
   the open- and closed-circuit resistance right at the jack?

   If you get teh same readings when measuring directly at the jack, teh
relay
   contacts may be partially welded. You will then need to replace the
relay.
   You can order a  replacement part from Icom Parts (1-800-USA-ICOM).

   Cheers for now, 73,
   Adam VA7OJ/AB4OJ



   -----Original Message-----
   From: [email protected] [mailto:[email protected]]On
   Behalf Of Doug Faunt N6TQS +1-510-655-8604
   Sent: Saturday, March 29, 2003 16:24
   To: [email protected]
   Subject: [Icom] Wierd, SEND relay on IC756PRO, again


   To bring this up again, I've got a very wierd situation here.

   I'm now seeing 1.5 ohms across the SEND relay when open (RX) and .6
   ohms when in TX mode.  It changes very reliably, but obviously, not
   enough.  It was working for a while, driving the TX circuit on a THP
   HL700B amp, which has got a 10K resistor to 5V for input signal to an
   IC.

   I've not done any significant debugging, but am very puzzled.
   Any ideas?

   73, doug

   ----
   Your Moderator: Dick Flanagan W6OLD, [email protected]
   Icom Users Net: Sundays, 1700Z, 14.315 MHz
   Icom FAQ: http://www.qsl.net/icom/


   ----
   Your Moderator: Dick Flanagan W6OLD, [email protected]
   Icom Users Net: Sundays, 1700Z, 14.315 MHz
   Icom FAQ: http://www.qsl.net/icom/

----
Your Moderator: Dick Flanagan W6OLD, [email protected]
Icom Users Net: Sundays, 1700Z, 14.315 MHz
Icom FAQ: http://www.qsl.net/icom/