[TenTec] Orion Heat Problems (Internal) SOLVED

[Leonard J. Umina]

SUMMARY:   THE ORION HEAT DISSIPATION CAN BE AN ISSUE DURING CONTESTS IN 
WARM CLIMATES
                     ESPECIALLY FOR LONG PERIODS OF OPERATION. **

(OR)              I SHOULD HAVE BOUGHT THE COOLING FAN BUT I'M NOT SURE 
IT WOULD HELP
                     ANYWAY.

In Northern California it's HOT.  My shack is air conditioned when I 
decide to run it, but our electric costs
are about twice the national average on a good day (when we actually 
have power) and that's often not
the case on hot days.  The nuclear reactor sits about 30 miles away idle 
because unions stole the re-bar
instead of installing it and the billion dollar albatross stands as a 
monument to one party politics and
the coordinated corruption that comes from having only one group of 
thieves in government, but I digress.

I am a casual operator most of the time, typically running my Orion for 
1-3 hours at a whack.  No problem
this way.  In the past I operated mostly QRO contesting and when I'm 
running the amp I have some extra
fans I place near it to keep things cool.  Inadvertently these helped 
the Orion but keeping the air moving.

This time I decided not to run QRO, which meant the Orion would be 
generating heat.  Consequently the amp fans were off.

A few hours into the contest my radio crashed.  I was changing bands and 
I got a garbled display.  I felt the
radio.  Quite warm.  Crap.  I quickly called a spare computer fan into 
service, wired it to my 12 volt supply and placed it on the case of the 
Orion over some vent holes.  This seemed to do the trick.  The shack 
usually gets
to about 85 degrees quickly, even when it's cold outside (in CA that's 
65 or lower) because of my super
overclocked computing system, not to mention lights and the radio, laser 
printer and so on.

I operated most of the remainder of SS with no heat issues....but it was 
only 85.

I decided to look into the heat issue a bit and surmised that the case 
ventilation is inadequate.  (common sense needs verification here, just 
ask the XYL).  As I looked over the problem I noticed that the only real 
opportunity to fix internal heat accumulation was the speaker cutout.  
Since I use an external speaker anyway I had to see what would happen.

Well, here are the results....

The internal speaker is simple to remove.  One screw, one connector.  
 From an engineering perspective, its probably a good idea to put a 
resistor on that connector to replace the speaker to keep the audio amp from
being unloaded. It depends on the design of the circuit, but be forewarned.

Removing the speaker appears to double the heat flow from the Orion, and 
that corner is where most of the heat appears.  In the Tim Taylor spirit 
though I wanted to do better.  I took my simple variable speed computer 
fan (with a little pigtail switch for H/M/L) and used some double sided 
mounting tape to secure it to the top
cover.   I set the switch for L which is silent and brought the power 
pigtail out the back of the radio under the
chasis cover (the wire is flat and thin, it fits).

I then ran 12V to the pigtail.

Heat problem GONE.  The radio runs very cool.

There could be some other solutions if you want the internal speaker.  I 
noticed TenTec uses a sponge layer
around the speaker since the case itself holds the speaker in position.  
It looks like removing most* of that
sponge layer (remove the speaker first, it lifts out) would still 
provide the mechanical stability of pressure from the top cover but 
there would be added airflow around the edges of the speaker.  It's not 
much - perhaps 1/16th to 1/8 of an inch around the speaker but that 
could be significant.

Be careful handling the speaker.  When I removed mine I noticed a coax 
and connector just below the speaker
that was seriously compressed.  Apparently if you put pressure on the 
case of the Orion it pushes in and the speaker can compress this 
coax/connector.  [The computer fan doesn't come close to taking as much 
room as the speaker]. (depthwise)

My fan is mounted at the square corners with double sided 3M tape.  It 
is just larger than the cutout.

So what caused the heat problem?

My guess is that the new firmware with the "hardware" mod to the radio 
causes more heat dissipation than the original design allowed for.  This 
happens because changing state (ie turning up the clock) can cause 
semiconductors to generate more heat.  I'm not sure if the band scope 
mods do this, or if it's a firmware
issue (yes, running a different program can cause heat changes because 
it can change the rate at which the
address lines toggle among other things.  Usually this is not a problem 
but it can be.  Just ask any PC gamer.)

It can also be a bad memory chip in my radio of course, but I doubt it.

One good thinkg is that the Orion has lots of room inside and its quite 
probable that someone with more mechanical ability that I have (none) 
could install an internal fan and keep an internal speaker.  My touch 
analysis (highly scientific - this sides warmer) indicates the heat 
comes from the front right side of the radio
during operation - right where the speaker is, so moving the speaker 
elsewhere is probably the ultimate goal.

As I write this the radio has been on for 24 hours and feels like its at 
room temperature (ie metal feels cool to the touch).

73,
Len
WT6G

* Not all.  Obviously you want the speaker to stay in place.  My bet is 
you can leave four triangle pieces
   around the speaker's square mounting bracket and get added airflow 
while still holding the speaker
   in place.  This solution has not been tested.  It WILL improve 
airflow but I opted for MORE POWER!

** No, I don't believe in global warming.  Its complete bullshit, and I 
can say that because I am not
    federally funded so I can speak the truth with impunity - at least 
until disagreement with the
    official politic becomes a hate crime.  Does anyone else out there 
remember what it was like when
    we had freedom?


PS There are some really cool computer fans out there.  I have one that 
has blue LED's in it and a variable speed control.  At some point you 
know that my quick mod is going to be doctored a bit because I'm 
wondering what the Orion is going to look like with blue light 
projecting from inside the case - or perhaps red.

The idea reminds me of the days when all radios had a warm red glow - 
kind of a visual that went hand in hand with the friendly times we 
enjoyed chatting with friends.

Now theres a product idea - LED lights under the radios wire front panel 
stand so you can see your logbook on field day with internal blue lights 
that change to red on TX, perhaps with modulation peaks....  Get to work 
MFJ, but I want credit for the idea.

I didn't start out this way, I once watched MTV for 20 minutes with my 
granddaughter!