[ICOM] Icom 765 - loss of audio & transmit !

[Will]

Thank you so much...........I'll dig out my spectacles and have a wonder
through the VCO in due course. I have ordered replacement trimmers from
Sprague-Goodman in NY and intend, whatever the case, to replace these
trimmers again
Thanks all round

Will

2009/9/21 Gary P. Fiber <gfiber at comcast.net>

> Could be a trimmer or the VCO is unlocked would be my guess. There is a
> voltage that is switched to turn on the VCO in use, might have a look at
> that when the problem is there.
>  If it were the LPL loop then the dead spots would repeat every few kHz
> all they way through the tuning range of the 765. Both are voltage
> measurements.It would not hurt to check both and the rest of the VCO
> alignment while he is looking at the PLL board.
>
> Gary K8IZ
>
> Will (by way of Dick Flanagan <dick at k7vc.com>) wrote:
> > I own a fairly late model ICOM 765. About 2 years ago I replaced the
> > VCO trimmers; these were bought direct from Icom UK as I was
> > experiencing many of the symptoms related to the need to replace
> > them. Raspy SSB audio etc etc.   I was, at the time, not convinced
> > that the replacement trimmers were of the ceramic type but, after a
> > call to their head office in Kent, England, I was assured that they
> > would do the trick. The replacement procedure went without a hitch
> > and all has been well since.  The past few days I have had the
> > following experiences. When I switch the rig on, I more or less
> > immediately lose any audio and am unable to transmit on 7 Mhz or
> > below. Switching bands up to 10, 14, 21 Mhz etc both transmit and
> > receive is fine but when I go back to 7, 3.5 or 1.8 Mhz, I cannot
> > hear a thing nor am I able to transmit.  I switch the rig off and
> > leave it for a while and, on a intermittent basis, when I switch it
> > on again, I can transmit and receive on 7 Mhz or below. The audio
> > then fails as does the ability to transmit. There is definately an
> > intermittent fault, be it a dry joint or a dodgy bit of switching on
> > the bands mentioned. I think I may have a faulty VCO trimmer but has
> > anyone else experienced this. In particular, the fact that it is only
> > affecting 7 Mhz and below ???  kind regards Will / GM0HKS
> >
> >
>
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