[Premium-Rx] HF-2050 Heating (Again)

[Williams, Barry]

I noticed that if you replace the screws in the HF-2050 power supply you
have to be careful to insure that the power supply is in full contact
with the top cover.  If you replace the top two screws loosely and then
invert the radio to replace the two screws on the bottom you can press
the power supply upward as you tighten the screws, then replace the
bottom cover and turn the radio back over to tighten the top two screws.
At this point the top cover should be .015 inches or so above the
chassis.  When you replace the screws in the top cover the cover will be
hard against the top of the power supply, this will conduct the heat
away much better than if the power supply is not against the top cover.
My radio had the power supply about .030 inches below the top cover so
there was no contact.  

 

This does not reduce the requirement for forced air cooling, but will
allow the power supply to operate at a much lower temperature.
Unfortunately the top of the power supply covers many of the cooling
vents, so cooling a power supply that is not in contact with the top
cover will be difficult even with fans.  Mounted this way the cover and
power supply are at the same temperature.  I would recommend checking
the electrolytics and tantalums, the easiest way is to buy new units and
replace them.  I used exact replacements for the large blue
electrolytics and for the small units I used whatever brand I could find
with a 105 degree C rating.  The receiver has been perfectly dependable
and now works like I expected.

 

Thanks,

Barry

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