[ICOM] Icom 765 Problem

Tue Oct 11 22:53:16 EDT 2005

Gary and group,

First, glad to hear from you and thanks for the tips on the 765.
Hope the new position is working out just fine, seemed to recall that you
did something with the railroad at some point?

The 765 problem.
You and the others were correct, the amps in question are located on what
Icom calls the "Main Unit" or main board.
It is accessed by removing the bottom cover of the radio.
Next remove about half a dozen Phillips screws which retain the main unit
circuit board to the metal chassis.
I then unplugged three multi-pin connectors located in the center/side of
the board.
With those connectors removed, the main board could be flipped over, keeping
the rest of the wiring and cables intact.
A close exam with a lighted magnify glass reveled a couple of faults.
First, the solder connections on the CW filter were cracked, simple matter
with the rework station to desolder and then properly resolder these.
This the filter unit which is attached to the board with two small
bolts/nuts.

Next I checked the connections in the AF amp stage, not really stood out as
bad, but I was able to rework all of those connections as well.
I touched up a few other questionable spots and then reassembled the unit.
It seems to play just fine right now, but time will tell.
The problem seems to present when the unit has been sitting unused for 2-3
days.

Once again thanks for the all help and suggestions from Gary and the group.

73 Bruce W1UJR 

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Gary Fiber
Sent: Sunday, October 09, 2005 12:12 AM
To: ICOM Reflector
Subject: RE: [ICOM] Icom 765 Problem

Hi Bruce,

Yes I am the same Gary, thanks for the nice words.
I still do a few shows for Icom but have not since Dayton. I also changed
jobs since then.
I now work for the Washington State Patrol. The job title is longer than my
arm.
I am an " Electronics Communications Systems Technician - Field ".
I am handle the surveillance electronic devices for the agency I work for.

Look those solder joints over well seems to me one of the techs found those
cracked pretty often when symptoms such as yours arose.
The display and S-meter are operating normally?

Gary K8IZ

At 07:08 PM 10/8/2005, you wrote:
>Thanks Gary, right on target.
>Removed the lower cover this evening, found the ICs bolted to the case.
>Tomorrow I will remove the main unit so I can properly rework the 
>solder connections.
>Of course will report back to the board with the results.
>
>Is this the same Gary who as a tech support rep for Icom?
>If so, I owe you many thanks, you helped me on a number of occasions, 
>and are one of the major reasons I bought and continue to buy Icom
products.
>
>73 Bruce W1UJR (ex KG2IC)
>
>-----Original Message-----
>From: icom-bounces at mailman.qth.net 
>[mailto:icom-bounces at mailman.qth.net] On Behalf Of Gary Fiber
>Sent: Saturday, October 08, 2005 5:09 PM
>To: ICOM Reflector
>Subject: RE: [ICOM] Icom 765 Problem
>
>Bruce,
>
>Going from old memory its seems to me if the radio is upside down, 
>knobs facing you the audio amps are on the left side using the chassis 
>as the heat sink, they are T)-220 cases or similar and the tabs are 
>bolted to the chassis. There were two of them as I remember the solder 
>joints on the leads would get cracked.
>
>Gary K8IZ
>
>
>At 10:16 AM 10/8/2005, you wrote:
> >Hi Paul,
> >
> >Do you recall which transistors in question, Icom schematic numbers?
> >Appears that they are located on the main board, right?
> >Was it a process to correct, did you need to remove the main board?
> >
> >Tnx - Bruce W1UJR
> >
> >-----Original Message-----
> >From: icom-bounces at mailman.qth.net
> >[mailto:icom-bounces at mailman.qth.net] On Behalf Of paul at w8aef.com
> >Sent: Friday, October 07, 2005 11:33 PM
> >To: ICOM Reflector
> >Subject: Re: [ICOM] Icom 765 Problem
> >
> >Check the audio output transistors for cold solder joints.  My '765 
> >had several, cold solder joints, that is.
> >
> >de Paul, W8AEF
> >
> >----- Original Message -----
> >From: "Bruce J. Howes" <bhowes at suscom-maine.net>
> >To: "'ICOM Reflector'" <icom at mailman.qth.net>
> >Sent: Saturday, October 08, 2005 2:25 AM
> >Subject: [ICOM] Icom 765 Problem
> >
> >
> > > 765 #2 seems to have developed a bit of a problem.
> > > I turned it on last night to very low audio, could hear the 
> > > signals, but at a very low level, even with the AF gain full open.
> > > Thinking that something may have happened to the speaker I removed 
> > > the top cover and inspected the connector and speaker, no fault found.
> > > Just for good luck, and using a highly refined technique, I 
> > > sharply rapped the chassis, BINGO, audio output full bore.
> > > Reinstalled the cover and she played fine for the rest of the evening.
> > >
> > > Tonight, similar problem, initial low audio, following by a good 
> > > audio of static crackling, almost like a thunderstorm.
> > > I removed the antenna, static is still there.
> > > The received audio, AM, sounds quite nice, aside from the static.
> > >
> > > Any suggestions?
> > > Thought this might be a case of the PLL wax migration fault, but 
> > > not sure as the audio is clear and not distorted.
> > >
> > > Tnx.
> > >
> > > 73 Bruce W1UJR
> > >
> >----
> >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/
> >
> >
> >
> >----
> >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/
>
>Gary Fiber K8IZ
>GROL PG-19-6691
>Washington State Resident
>
>
>----
>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/
>
>
>
>----
>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/

Gary Fiber K8IZ
GROL PG-19-6691
Washington State Resident

----
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/