[ICOM] got the ptt fixed

Sat Jan 9 14:08:02 EST 2010

Hi Vern. Go to Icom America, then to Amateur. You should find the 761 
listed, then you will find the different problems. Before someone 
directed me there, (I had been MANY times, but just forgot about it), I 
had a horrible intermittent with my 761 getting hard of hearing. All I 
had to do was lightly (and I mean LIGHTLY!!!) tap the radio ANYWHERE, 
and it would be ok for a short time. I can't tell you how many times I 
was in it, tightening ground screws, etc. It always worked OK for a 
while and the problem would come back. A fellow poster on here directed 
me right to the Icom solution. Replace the norm/preamp relay.
I think it was RL151, but not sure.
They are still available but being the stubborn person I am, I 
disassembled the radio to get to that board. Took the plastic cover off 
of the relay and used a small piece of business card with Deoxit-5 on 
it. That was well over a year ago and it's been OK ever since.
I'm willing to bet you have a dried out cap in the display circuit.
Heck, I had a small digital clock that did the same thing. Strange 
digits. Since I had nothing to lose, I took it apart. I removed the 
caps and measured their ESR. Sure enough , NFG. Replacement of those 
caps restored the clock.

regards,

ron
N4UE

-----Original Message-----
From: Fern <crc at cyberlink.bc.ca>
To: ICOM Reflector <icom at mailman.qth.net>
Sent: Sat, Jan 9, 2010 1:19 pm
Subject: [ICOM] got the ptt fixed

Hi Ron: Thanks for your reply. This radio has already had the cursed 
pll vco
caps replaced already by a previous owner. I wasn't going to bed till I 
found
the problem. One of the grounds at the mic connector was the culprit 
(it was
broken off so it was intermittent) plus the manual xmit switch uses the 
same
ground (which is what kind of threw me off for a bit). I did make one 
contact on
75 meters (at 2:00 am) when I finally put the 761 on the air and got 
good
reports. I like the speed of the automatic antenna tuner. I just made 
some
contacts this morning with some of the guys that I know (again on 75 
meters) and
the transmit audio is great. Initially, when using the processor, I was 
told
that the audio was on the rough side but I see that one has to back off 
on the
mic gain when the processor is switched on. I don't have to do that 
when using
the old icom 745. I'll go back into the alignment of the 761 ( I did 
get a copy
of the service manual with it) and see if I missed an
adjustment to fix that problem. That radio will put out an easy 150 
watts out
if it's cranked up but best to leave at around the 100/110 watts level. 
It's a
bit of a job to get at the second oscillator adjustment as it's buried
underneath the switching power supply so one has to temporarily get the 
ps out
to get a the reference trimmer as it was off enough to want to correct 
it. The
hm-36 hand mic that came with it doesn't work as the previous owner's 
pussy cat
had chewed up the cord but I may just have a replacement cord around. 
I've used
an hm-12 which work ok but tried an hm-23(similar to hm-12 but has dtmf 
pad on
the back of it) and it's an even better mic as the frequency response
accentuates the high's a bit more.
So all I have to worry about is why did the frequency disply show 77E
instead of the frequency (hopefully it's just a bad connection 
somewhere's and
not in the pll or vco circuitry).
Where is this "knowledge base" site that you're referring to? I google 
for
the 761 problems last night but didn't get anything.
73 from Fen VE7GZ

----- Original Message -----
From: <bonddaleena at aol.com>
To: <icom at mailman.qth.net>
Sent: Saturday, January 09, 2010 6:32 AM
Subject: Re: [ICOM] no ptt transmit on IC-761

> Hi Fern. Did you look on Icon's "knowledge base"? I bought a 761 
years
> ago, during a move. It had (has) a great receiver, but the transmit 
was
> dead. I feared it was the finals, but a trip to Scott at MTS 
confirmed
> it was the dreaded 'crummy trimmer syndrome". He replaced them all 
and
> aligned it for a better than reasonable price and other than a dirty
> T/R relay (easy fix), it has been perfect.
> I sure wish I had a buck for every problem those $%^&* caps have
> caused!!
>
> ron
> N4UE
>
>
> -----Original Message-----
> From: Fern <crc at cyberlink.bc.ca>
> To: ICOM Reflector <icom at mailman.qth.net>
> Sent: Sat, Jan 9, 2010 1:58 am
> Subject: [ICOM] no ptt transmit on IC-761
>
>
> I just acquired an Icom IC-761 today. At times, the radio will not
> transmit with
> ptt (it's definitely not the microphone as I've tried 3 different 
mics)
> but at
> times it will work using the VOX option. Also, the manual xmit key 
will
> not
> key up the transmitter. I have done the cpu reset with no 
improvement.
> It lost
> the frequency display at one point and then came up with 77E shown in
> lieu of
> the frequency. Shutting the radio off and then back on will restore 
the
> frequency display but still no manual ptt for xmit. Has anyone seen
> this
> problem? Any help with this would be greatly appreciated. 73 from Fern
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> To support QSL/QTH.net: http://www.qsl.net/donate.html
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> To support QSL/QTH.net: http://www.qsl.net/donate.html

-------------------------------------------------------------------------
-------

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.430 / Virus Database: 270.14.130/2607 - Release Date: 
01/08/10
07:35:00
----
Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
Icom Users Net: Sundays, 1700Z, 14.316 MHz
Icom FAQ: http://www.qsl.net/icom/
To support QSL/QTH.net: http://www.qsl.net/donate.html