[ICOM] Icom R-8500 PLL Problem

[Ken Simpson, W8EK]

The oscillator was the problem for sure.  I used some cleaner in that 
area, and it came back to life, and has been working for close to a 
day now, and seems to be working all of the time.  Hopefully it is fixed!

Thanks.

73,

Ken, W8EK


Adam Butler wrote, On 7/2/2011 2:05 PM:
> Ken,
> 
> Check and see if the trimmer cap for the 
> oscillator adjustment is shorted. You may be able 
> to clean it up by rocking it back and forth a few 
> times but as the other person said, plan on 
> changing it out if this does fix it as it will 
> come back to haunt you.  The adjustment for that 
> oscillator should be pretty straight forward and 
> only a frequency counter is needed from what I recall.
> Why a trimmer just sitting there shorts is beyond 
> me but the others are correct and several Icoms seem to have trimmer issues.
> I never had any issues when I had my 8500 but I 
> sold it recently and only use the older R7000 and 9000 receivers.
> 
> I do not know why my replies are showing me as 
> Adam! I'm really Steve!  I need to look into that 
> as I have it set correctly for this email account.
> 
> Good Luck!
> 
> Steve
> 
> At 12:49 PM 7/2/2011, you wrote:
> 
>>Thanks very much.
>>
>>It appears that the problem is in the oscillator.  I turned it upside
>>down and took it apart, and then fired it up to see what would happen.
>>   Same problem.  With it turned on, I carefully banged on the
>>oscillator module, and BINGO.  I heard white noise, as I had the
>>squelch open and the audio turned up.  It stayed that way (that is
>>apparently working, with the display no longer blinking) for a minute
>>or two, until I turned the receiver right side up.  Now it is back to
>>the way it was, and nothing seems to bring it back to life.  But at
>>least that does say that it is likely in the oscillator area.
>>
>>Time to put the scope on it, and see what goes (or does not go), and
>>if the problem can be fixed easily.  Of course the easy fix would be
>>to add the extra high stability CR-293 oscillator module, but at about
>>$300, I think I will wait on that!
>>
>>Thanks.
>>
>>73,
>>
>>Ken, W8EK
>>
>>
>>GGLL wrote, On 7/2/2011 12:53 PM:
>> >       Ken, if the reference oscillator trimmer is faulty, the basic
>> > oscillator would not work, and so the whole radio. Icom has many
>> > problems with PLL and associated (which become dirty with time) trimmers.
>> >
>> >       Check the ref osc trimmer noting its 
>> position and turning it back and
>> > forth a couple ot turns, although this may bring it to working condition
>> > again, it is wise to replace the component as soon as you can.
>> >
>> > Regards
>> > Guillermo - LU8EYW/W.
>> >
>> > El 02/07/2011 11:00, Ken Simpson, W8EK escribió:
>> >>
>> >> Thanks, Adam.
>> >>
>> >> The problem I have is different that his (at least I think so), in
>> >> that it is simply the blinking display, that I think indicates a PLL
>> >> problem.
>> >>
>> >> I hate to send it out for repair, especially if it is something simple.
>> >>
>> >> However, if a PLL is unlocked, I would think it would only be one PLL,
>> >> and would work on some frequencies and not others.  That is why I am
>> >> wondering if I am missing a jumper, or something simple like that.
>> >>
>> >> Thanks.
>> >>
>> >> 73,
>> >>
>> >> Ken, W8EK
>> >>
>> >>
>> >> Adam Butler wrote, On 7/2/2011 12:32 AM:
>> >>> Not sure if this will help but I came across a post at radioreference
>> >>> today from a guy with a similar sounding problem. He did not go into
>> >>> detail as his post was to rant about shipping costs back to Icom but
>> >>> maybe you could ask him what he knows of the issue.
>> >>>
>> >>> The post is here:
>> >>> 
>> http://forums.radioreference.com/icom-receivers/215381-r8500-canadian-service-depot-finally.html
>> >>>
>> >>> At 05:33 PM 7/1/2011, you wrote:
>> >>>
>> >>>> I have an Icom R-8500 receiver that came from a silent key.
>> >>>>
>> >>>> It would appear that it has a phase locked loop problem.  The
>> >>>> frequency on the display is flashing all the time, regardless of what
>> >>>> frequency I put in.  That also means no audio, basically like the
>> >>>> squelch is fully on.
>> >>>>
>> >>>> However most every other function appears to work.  I did do a reset,
>> >>>> and that makes no difference.
>> >>>>
>> >>>> It is almost as if there is a jumper some place that is needed, but I
>> >>>> can not find any information like that.  Of course it is a bit hard to
>> >>>> ask the silent key about it!
>> >>>>
>> >>>> Any one have any suggestions?
>> >>>>
>> >>>> Thanks.
>> >>>>
>> >>>> 73,
>> >>>>
>> >>>> Ken, W8EK
>> >>>>
>> >>>> Ken Simpson
>> >>>> E-mail to W8EK at FLHam.net or W8EK at arrl.net
>> >>>> Voice Phone  (352) 732-8400
>> >>>>
>> >>>>
>> >>
>>----
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> ----
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> Icom Users Net: Sundays, 1700Z, 14.316 MHz
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>