[R-390] Cleaning the Megacycle bandswitch

[dog]

The early 2nd Xtal oscillator switch (148) is indeed phenolic, I still 
have it out. I'm sure the older one is too, but I'll have to remove it 
to check. It needs cleaning anyhow. I have some De-Ox I can be sparse 
with. Good thing I didn't spray that old can of 'Crown 8070 Electrical 
88' cleaner on it. That stuff was great though, but you can't get it 
anymore. It was great on pots.


On 10/10/2018 20:22, Guido Santacana wrote:
> You are correct Larry I had a bad experience using Deoxit on a Phenolic
> wafer switch in a multiband radio.Since then I never sprayed Deoxit on
> Phenolic wafer switches. What I did with the R390A was to apply it with a
> fine brush only on the contacts being extra careful to avoid letting much
> Deoxit on the wafer. It worked but your mileage may vary. I am sorry about
> not mentioning that detail before but thanks for bringing it up.
>
> 73s
>
> Guido
>
> On Wed, Oct 10, 2018 at 8:02 PM Larry H <larry41gm at gmail.com> wrote:
>
>> I believe that most of the RF deck switches are ceramic, so a little
>> cleaner or solvent on them is not a problem.  But, the 2nd xtal osc switch
>> is phenolic and it can absorb chemicals and damage it by reducing it's
>> insulating characteristic.  Care to not get any cleaners or solvents on
>> them is important.  Deoxit is good to use on them, but not on  the phenolic
>> part.
>>
>> Regards, Larry
>>
>> On Wed, Oct 10, 2018 at 7:32 AM Guido Santacana <gsantacanav at gmail.com>
>> wrote:
>>
>>> What I have done to clean the switch in the rf/crystal deck is to go over
>>> it carefully with a camel hair brush dipped in Deoxit. This is done just
>>> before returning the RF deck to the main chassis. When everything is back
>>> in its place I move the switch through all bands. It has worked for me.
>>>
>>> 73s
>>>
>>> Guido KP4FAR
>>>
>>> Sent from my iPhone
>>>
>>>> On Oct 10, 2018, at 9:37 AM, dog <agfa at hughes.net> wrote:
>>>>
>>>> It appears that the gain in my 390A will change over time. I've tried
>>> changing tubes to no avail. Then I noticed that if I rocked the Megacycle
>>> Change the gain goes back to 'normal' and stays there for a while. It's
>>> also noisy changing bands. What is the recommended procedure to clean
>> that
>>> switch?
>>>> Dave
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