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[TenTec] Orion Heat Problems (Internal) SOLVED

To: tentec@contesting.com
Subject: [TenTec] Orion Heat Problems (Internal) SOLVED
From: "Leonard J. Umina" <len@brasspounders.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 03 Nov 2008 09:17:54 -0800
List-post: <mailto:tentec@contesting.com>
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!





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