[TenTec] Cooling the Orion

[Tommy]

I do not recommend this mod as there is no engineering/technical justification for it, however it  is my personal choice to do so.

Having been a microwave circuit design engineer and having designed several integrated circuits in my career, I have an 'obsession' about keeping heat out of solid state devices. My Orion has the Ten Tec fan on the heat sink. The Orion sits in a custom shelf, open in the front, back, and both sides. It sits with the bail up  and about four inches clearance on the top in front, and about seven inches clearance on the top, in the back.

During normal operations, meaning with it running all day, I observer the top of the case getting, not hot, but very warm to the touch. (It is most likely designed to withstand this (small) heat build-up, but I just don't like it. A digital therometer just placed on top of the Orion, shows a 15 to 20 degree F temperature rise above ambient during normal operation (primarily CW).

The Orion has one of the best sounding internal speakers I've ever heard on a Ten Tec piece of equipment, however I use either headphones or an external speaker. Dead PC power supplies normally have a 12 vdc fan in them that seldom go bad. The PC pwr supply fans I have in my junk box have mounting hole spacings of 3 1/4 inch. Remove the Orion top cover and the internal speaker has mounting holes that are spaced 3 1/4 inches. The depth of the internal speaker is deeper than that of the pwr supply fans.

VERY BASIC

Remove the speaker plug from it's socket in the top of the Orion. Remove the speaker bracket, then the  four screws holding the speaker to the custom bracket.The holes in the speaker bracket are tapped, so find some mounting screws that will fit in the tapped holes. (Do not use a washer/nut on the upper side of the speaker bracket as the top cover would no longer fit on the Orion.) Select the length of the fan mounting screws so that with the fan mounted, the end of the screw is at least 1/16 inch below the rubber vibration pad on the speaker bracket.

The old PC pwr supply fan is noisy when run at 12vdc. I added a 100 ohm  resistor in series with the +12vdc wire going to the fan. (If you do this, don't forget to put heat shrink tubing over the resistor and the soldered leads.) The points I selected to obtain +12vdr is the very same point where the rear +12vdc RCA connector obtains it's voltage and the ground connection is the same point on the vertical PC board in the rear  of the Orion that is used for the +12vdc RCA connector shell. I very carefully soldered the + and - fan dc supply leads to those two points. I ran the fan wires along the vertical aluminum panel on the right side, internally, of the Orion and I used 'spot-tie' to hold it snuggy to the other wires along that same location.

RESULTS

Not earth-shattering -- doesn't improve/degrade performance the least bit -- but now there in no temperature rise with  the digital therometer sitting on top of the Orion for a full day's operation. The top cover remains at ambient temperature all day. The main thing that may be gained by doing this is some help in possibly preventing long-term failure problems due to sustained heat environment in the Orion.

As I said, I'm  kinda obsessed with keeping all solid state devices as cool as possible. Took about  2 hours to complete.

Tom - W4BQF