[R-390] Thermal Stability and Top and Bottom Covers?

[David C. Hallam]

I have never had a 390A, but I have always run my 390 with a small 
muffin fan on the underside directed at the the series pass voltage 
regulator tubes.  Between the rectifiers and the regulators, a lot of 
heat is generated.  I don't know about thermal stability, but the 
components will be a lot happier.

David
KW4DH


On 10/16/2016 12:22 PM, Bob Camp wrote:
> Hi
>
> The 390 runs hotter than the 390A so it is a bit more “happy” with a bit of
> moving air. Spacing the radios about 3” apart in a normal open back rack
> is fine for the 390A. Maybe a bit more space is better on a 390. It also depends
> a bit on how many you are stacking. If you have three 12’ racks full of radios all
> next to each other,  that will require different cooling than two radios in an
> otherwise empty rack.
>
> Bob
>
>
>> On Oct 16, 2016, at 12:11 PM, Jerry O. Stern <jsternmd at att.net> wrote:
>>
>> I am rack mounting my R390A and R390 and have always read that covers should
>> not be used in cabinets.  My cabinet has a wide open rear, dDo I need to
>> install a fan for circulation?  Would a fan create too much thermal
>> fluctuations to affect performance noticeably?
>>
>>
>>
>> Jerry NY2KW
>>
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