Hi Art... thanks for your interest... Here are my responses to your questions:

Q : 1) Does the display show anything when it starts acting up ?

The display behaves normally during this problem.. I can change frequencies, bands, and other options. The volume and everything else
works as well. It's only white noise that comes up... the station (and all
stations) are gone.

2)
Did you try using an external p/s and/or good batteries, and if so do
you get same response ?

I have tried new akaline, and fully charged NiMH batteries.. several sets.
They don't make a difference.


3) Before taking it apart have you tried
cooling the whole radio by putting it in a fridge (not the freezer )
for a little while and see if the problem goes away (temporarily)?

No! I haven't tried that yet, but I will give it a shot today and see what happens! I'll report back here.

Yesterday, I left the radio out in my 40F degree garage for about 9 hours, then turned it on, while I was out there with it.

No difference in radio behavior... FM came in strong for 2 mins, then disappeared. AM was completely dead.

Do you still think it could be thermal related?

On Mar 21, 12:06*am, OnkyoMan
wrote:
Yesterday, I left the radio out in my 40F degree garage for about 9
hours, then turned it on, while I was out there with it.

No difference in radio behavior... FM came in strong for 2 mins, then
disappeared. *AM was completely dead.

Do you still think it could be thermal related?

--
OnkyoMan

It is too early tell . Have you tried using an External p/s and notice
any difference ? While powering it up can you measure the current and
notice if it is same as when it goes into the non-fuctional
condition ? Also , by tapping on the cabinet , is there an
intermittant connection somewhere ?

On 03/20/2011 09:06 PM, OnkyoMan wrote:
Yesterday, I left the radio out in my 40F degree garage for about 9
hours, then turned it on, while I was out there with it.

No difference in radio behavior... FM came in strong for 2 mins, then
disappeared. AM was completely dead.

Do you still think it could be thermal related?



I don't think you can find a fault that way. A cold solder joint or a
faulty component would be very localized. The current flows through some
abnormally high resistance and heats that area enough to deform it
relative to surrounding areas. If you freeze the whole thing, nothing
changes.

I've gotten some advice that it might be a trimmer capacitor which has been known to go bad on these radios. Does that make sense as a possibility to any of you?

Can you recommend a good source these capacitors?

Thanks,

Matt

On 3/21/2011 2:43 PM, OnkyoMan wrote:
I've gotten some advice that it might be a trimmer capacitor which has
been known to go bad on these radios. Does that make sense as a
possibility to any of you?
[...]


Probably not, because a trimmer would be unlikely to be in both the
FM and shortwave sections since they probably use totally separate
RF and IF amplifiers.

Whatever the cause is, it is in a section that is common to all bands.

Of course, carefully changing out a trimmer capacitor shouldn't
_hurt_ anything as long as you have the ability to readjust it
properly once installed. Also, there may be message threads
somewhere out there in cyberspace that describe the symptoms caused
by that particular trimmer.


Best of luck,


Kevin, WB4AIO.
--
http://nationalvanguard.org/
http://kevinalfredstrom.com/

On Mar 21, 9:57*am, dave wrote:
On 03/20/2011 09:06 PM, OnkyoMan wrote:

Yesterday, I left the radio out in my 40F degree garage for about 9
hours, then turned it on, while I was out there with it.

No difference in radio behavior... FM came in strong for 2 mins, then
disappeared. *AM was completely dead.

Do you still think it could be thermal related?

I don't think you can find a fault that way. A cold solder joint or a
faulty component would be very localized. The current flows through some
abnormally high resistance and heats that area enough to deform it
relative to surrounding areas. If you freeze the whole thing, nothing
changes.

The original symptom was stated as : A) works for a few seconds B)
reception turns to Noise (and no audio) on all bands . When left in a
cold garage at 40* for 9 hours FM started to work for Whole Two
minutes ! Thermal as thermal can be .

Thank you for your suggestions!

It is starting to look a bit more like the problem might be centered the trimmer capacitor. One user told me to simply rotate that capacitor a bit,
and now the radio works perfectly on FM. SW and MW are still completely dead though... the volume only amplifies the white noise.

Now I'm trying to ID a good source for trimmer capacitors. If anyone has a suggestion, please let me know! I'd like to find a high quality replacement, if possible.

Thanks,

Matt

On 3/22/11 15:22 , OnkyoMan wrote:
Thank you for your suggestions!

It is starting to look a bit more like the problem might be centered the
trimmer capacitor. One user told me to simply rotate that capacitor a
bit,
and now the radio works perfectly on FM. SW and MW are still completely
dead though... the volume only amplifies the white noise.



Check the antenna select switch, and the DX/Local switch. It
sounds like you have some oxidation in your unit. These switches, if
oxidized, will produce the very symptoms you describe, especially
true if FM is now working.

Throw these switches several times. Move the toggle in a circle
until you get some change in the noise.

I experience this regularly with my own Sat 500.


Now I'm trying to ID a good source for trimmer capacitors. If anyone
has a suggestion, please let me know! I'd like to find a high quality
replacement, if possible.


IF it's working, you may not need one. It sounds like you have
oxidation on the rotor contact, which is preventing this trimmer
from completing it's circuit configuration. Now that you have it
working, move the rotor back and forth a few times, it will be fine
for quite a while.


Thanks,

Matt

On Mar 22, 4:14*pm, "D. Peter Maus" wrote:

* *Check the antenna select switch, and the DX/Local switch. It
sounds like you have some oxidation in your unit. These switches, if
oxidized, will produce the very symptoms you describe, especially
true if FM is now working.

* *Throw these switches several times. Move the toggle in a circle
until you get some change in the noise.

* *I experience this regularly with my own Sat 500.

Could you get the same results with a squirt of cleaner in the switch
innards?