I have a problem with my ICOM 735 transceiver. It has done me well for 23
years now, but just recently I have noticed raspy CW and SSB signals on
receive, on an intermittent basis. This problem comes and goes, often in
long intervals and does not seem to be affected by temperature. It sounds
simply like an unclean signal with a raspy note on top of it. I am so far
unable to determine if this affects my transmit signal or not, I did get a
poor report once during this condition, but during another transmission at
another time I did not. I have the complete service manual for this rig,
but am a bit unsure where to start.

Any ideas appreciated.


Larry VE7EA

"Larry Gagnon" wrote in message
newsp.t5ngu3n2aiss39@localhost...
I have a problem with my ICOM 735 transceiver. It has done
me well for 23 years now, but just recently I have noticed
raspy CW and SSB signals on receive, on an intermittent
basis. This problem comes and goes, often in long
intervals and does not seem to be affected by temperature.
It sounds simply like an unclean signal with a raspy note
on top of it. I am so far unable to determine if this
affects my transmit signal or not, I did get a poor report
once during this condition, but during another transmission
at another time I did not. I have the complete service
manual for this rig, but am a bit unsure where to start.

Any ideas appreciated.


Larry VE7EA


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


Maybe your receiver is being desensed by a nearby and new
source of strong RF energy?

Could it be that you left the noise blanker on and are
noticing its effects on strong signals?


Ed, NM2K

On Mon, 28 Jan 2008 21:14:52 -0800, Ed Cregger
wrote:


Maybe your receiver is being desensed by a nearby and new
source of strong RF energy?

No, I thought of that. Another rx nearby not being desensed.

Could it be that you left the noise blanker on and are
noticing its effects on strong signals?

No, but thanks anyways - I've been through all the obvious stuff...


Larry

On Mon, 28 Jan 2008 09:14:53 -0800, "Larry Gagnon"
wrote:

I have a problem with my ICOM 735 transceiver. It has done me well for 23
years now, but just recently I have noticed raspy CW and SSB signals on
receive, on an intermittent basis. This problem comes and goes, often in
long intervals and does not seem to be affected by temperature. It sounds
simply like an unclean signal with a raspy note on top of it. I am so far
unable to determine if this affects my transmit signal or not, I did get a
poor report once during this condition, but during another transmission at
another time I did not. I have the complete service manual for this rig,
but am a bit unsure where to start.

Any ideas appreciated.


Larry VE7EA


Generally this is due to the VCO trimmer caps and may be localized to
one VCO currently. I forget the switching range of the VCO but that
should be written in the service manual likely in the theory of
operation section of the service manual.

If one trimmer cap is in trouble all will be soon. Icom has been
using some ceramic dieletric caps in place of the plastic dieelectric
caps. Changing out the caps generally cures the trouble.

Gary K8IZ

On Tue, 29 Jan 2008 05:24:03 -0800, Gary P. Fiber
wrote:


Generally this is due to the VCO trimmer caps and may be localized to
one VCO currently. I forget the switching range of the VCO but that

Gary: yes I think you've nailed it. I was pointed to the Icom knowledge
base at their website and it was there too. Thanks for your help!