Heat solution- surgery required

[User_0423]

EDIT- 6/28/18: I have now completed the addition of the large heat sink and it is running cool. See my post below for details.

I’ll open with the disclaimer that this solution is not for everyone, and there are easier ways to keep your Tablo cool enough. Since my warranty is up, I live in the south, and I’ve had a few heat related issues, I wanted to try out an idea to properly solve the heat issue on the Tablo. Under normal operation in my equipment room, it gets hot to the touch. After having some issues I learned here to stand it on its side, but this is not a long term solution.

I cannot add any pics here since I don’t see a way to attach them, and apparently Photobucket no longer allows forum links. Looking for a better solution and liking to over-engineer things, I looked at the parts involved.

The bottom of the Tablo is a thin plastic cover that has low grooves that terminate in vents on either side. It has 4 legs that press a steel heat plate against the upper case and hold the circuit board in place. Under this is a steel plate that acts as a heatsink. It is attached via thermal compound to the circuit board. The plastic cover acts as an insulator since it does not conduct heat as well as metal. This of course keeps us from burning our fingers worse when we touch it. The various laptop cooler/heatsink (defroster tray) suggestions here make use of this and reduce the heat to a decent level, but are not the best thermal solution since the plastic insulates some of the heat.

Since I had a number of computer fans leftover from various projects, I found an 80mm one that would fit in the center of the plastic cover. The idea here is to mount the 80mm fan so it will cool the steel plate via airflow. To do this, you have to remove and drill the plastic cover. I marked the mounting holes for the fan and then drew diagonal lines from them to find the center. After I did that, I used a 3" hole saw to cut out the center hole. Tip: Use a slow speed portable drill and clamp the plastic in a vice and support it with your free hand. I tried using a drill press w/ machinist vice and snapped off two of the legs. Then drill out the 4 mounting holes to 13/64" and use regular computer case fan screws to mount the fan. The best fan to use is a USB powered one, but since mine was a 12V case fan, I used an old power supply via some adapted wiring.

This fan is high RPM and too noisy, but stage 2 will involve a better heatsink to replace the damaged plastic cover. I’m thinking a 7 x 4.5" bottom unit will screw on and I can use nylon standoffs in the holes to provide proper clamping pressure. I’ll likely use a tall (3.5") heatsink so I can use it as a base and then install the 80mm fan on one end.

I’ve had my Rube Goldberg setup running on its side for several hours now and the bottom is cool.I noticed when getting channel info the Tablo does not seem to lag as bad as it had been doing. Using a laser thermometer in a 77 degree ambient room, with the fan on, the plastic cover measured 81.5 degrees.

Turning the fan off and waiting just 5 minutes returned a temperature of 87 degrees. With the TV on and tuned to a local channel, I saw 98 degrees after 5 minutes (10 total w/o the fan).

Turning the fan on, it dropped to 89 degrees in under a minute. After 2 minutes it was around 83 degrees.

My conclusion here is that the heat plate as designed is inadequate. With a proper heat sink and a fan, the device should last far longer.
EDIT- Here’s a pic of the installed fan. Thanks for the tip on how to upload, I’m not a fan of icons.

[zippy]

Why waste more energy powering a fan to cool the heat sink.

Just go with a stirling cpu cooler.

[Daniel454]

It may vary with time of membership or # of posts but I do see where pics can be added via the “upload” button, the 7th icon over when replying to posts…

But just for the record, not sure why, but not everyone experiences these heat problems… Just passed my 3rd year anniversary with my 4 tuner Tablo (and my parents have had one for about 18 months), no fan, not sitting side ways, nothing.

Mine sits on a shelf about 12 inches from the ceiling in a non air conditioned closet (door closed) along with a router and 2 hard drives.

Rooms around the closet are kept at no less than 74 degrees during the day.

Never, not a single time, have I had ANY heat issues with the Tablo. The few issues I have had were almost entirely caused by signal issues. (Or Roku firmware issues).

In fact the first year I had it, I even had it powering both the connected HDD as well as it provided the power for my inline antenna pre-amp… Still no issues.

[Daniel454]

I say all that because I don’t want people reading these forums and thinking they ALL have heat issues.

If yours does, I apologize and I really like the out of box thinking and effort put into doing the modification and appreciate you sharing it with others.

[User_0423]

Thanks for the info. I have uploaded a pic of the fan installed.

[User_0423]

[quote]Why waste more energy powering a fan to cool the heat sink.

Just go with a stirling cpu cooler.[/quote]
Why waste more time reading the first sentence of my post?

I’ll open with the disclaimer that this solution is not for everyone, and there are easier ways to keep your Tablo cool enough.

[zippy]

But you closed your post by implying that the heat plate design is inadequate and with a proper heat sink and a fan, the device should last far longer.

If one were to accept that postulate then any solution is possible. Even keeping the tablo next to the beer in the refrigerator in your man cave.

[User_0423]

[quote]But you closed your post by implying that the heat plate design is inadequate and with a proper heat sink and a fan, the device should last far longer.

If one were to accept that postulate then any solution is possible. Even keeping the tablo next to the beer in the refrigerator in your man cave.[/quote]
My apologies. I forgot the less than golden rule of the Internet- if you post you’re giving away $100 to everyone in the world, someone will come along and complain that you’re not giving away $101.

I closed my post based upon my experience with my Tablo. Why don’t you ask someone that has experience designing electronics about how well components do with heat? Unlike automobile engines that operate more efficiently at a certain temperature (hence the use of thermostats), components do better and last longer when cooler. As another example, why do CPU overclockers seek better cooling when overclocking? Just because a component can exist in a 125F environment does not mean that is an optimum environment for it.

Logically, any solution is not possible for various reasons. For example, let’s try to buy a “stirling cpu cooler”. Since I did not know what that was, I looked it up. These use the “Stirling engine” that was tried by MSI back in 2008. The first obstacle is where do you buy one? The web buzzed about the idea 6-10 years ago, but now no one is selling one at retail. If they are, it’s a pretty well kept secret. Even Stirling Cryogenics has no retail link on their site. The issues with a Stirling cooler then are twofold: Supply and cost. Since the design is complex, it is likely very expensive to buy. Contrast this with the below cost of around $30 for the fan and tools, which uses common parts and tools. From what I’ve learned so far, even adding a large heatsink to replace the bottom cover would not cost over $50.

Next, the fact that heat complaints in this forum are ongoing (I counted about 50 in a search here), this is indicative that there is a problem with the original design. The Tablo is a fairly recent product, so the user data will be more limited than a device that has been in production for say 10 years. Users have taken steps to solve the problem such as turning the unit on its side, but that is not a long-term solution, more like a band-aid. The issue is heat and how to remove it. The solution is to remove the heat. The most affordable way to remove heat is via air cooling. Even liquid cooled engines and CPUs use air to cool the cooling medium via a radiator. As I inferred in my post, plastic is an insulator. To effectively transfer heat, a conductor (the opposite of an insulator) is needed. The best way then to cool the Tablo is to either attach a conductor to the steel heat plate and passively (heatsink) or actively (via a fan) cool that or cool the heat plate. My fan idea does the latter in that the plastic is cut away so cooling air can directly reduce the temperature. As my brief temperature research showed, the fan idea is effective. In my case, it cost me nothing since I had the tools and parts needed. If you had to buy everything, it would still be around $20-30 depending on where you source the parts.

[zippy]

Since you like to tinker no one said buy versus build a stirling engine that powers a fan.

And yes I was in R&D for 42 years. But I’m not afraid of the heat. Is the heat exceeding 130F? I have multiple tablo units approaching the 4 year mark. Still humming alone with the original WD Element disks. Sometimes I wish they would die so I could purchase a newer model.

And I live in the southwest. You don’t know what heat is until you hit the 100F mark. But it’s a dry heat.

[User_0423]

I was in R&D for 42 years.

Then why make a statement you know to be untrue?

[quote]…with a proper heat sink and a fan, the device should last far longer.

If one were to accept that postulate…[/quote]
The use of heatsinks and fans to extend component life is a widely accepted practice. Here’s an example from an engineering student:

1001.3751.pdf

However, for the last few years, as the processors got more and more powerful, it has become mandatory that a CPU requires a multifin heat sink as well as a fan that ensures reasonable air flow through the cooling fins as the overheated processors exhibit a shorter maximum life span and often results in problems like system freezes or crashes [2].

It’s good you have not had a heat issue with your Tablo. Many others including me have.

And I live in the southwest. You don’t know what heat is until you hit the 100F mark. But it’s a dry heat.

Again, good for you, but inapplicable to me. In the summer I’ve ridden my motorcycle in 116F indicated ambient on a freshly paved road in riding gear. That’s as hot as I’d care to be. I feel the same way about my electronics, especially when they have exhibited problems.

BTW, a day later and still cool running.

[zippy]

“The use of heatsinks and fans to extend component life is a widely accepted practice”

Did the new hdhomerun move away from fans. How about airtv and the airtv player. Roku had only one model that contained a fan and they abandoned that design. FireTv sticks and dongles. Chromecast?

And as my IPhone"s CPU got more and more powerful and contained more memory I often complained to Apple about the noisy fan. Thank God Apples tablet has a beefed up fan.

Spend some time in the Coachella valley.

[User_0423]

Looks like you’re just here to argue, so I’m not going to waste any more time on you. It is counterproductive to what I came here to do.

The point of this thread was to offer a solution for those that needed it, and that has been accomplished. When I obtain a larger HS to replace the bottom panel I’ll post an update.

[Radojevic]

Roku had only one model that contained a fan and they abandoned that design.

Yes, my Roku 4 has a CPU fan, and ran around 55C.
My Roku Ultra, with no fan, runs around 75C.

Abandoning a design doesn’t mean the design was flawed.

Your Tablos are running hot, and straight… you won the Tablo components lottery.
Others won’t be so fortunate with the same ambient temperatures, and humidity levels.

[User_0423]

I bought a fairly large (7.5" x 4.75") heat sink on eBay for about $33 shipped. It’s large enough to cover the bottom of the Tablo and I was able to align the bottom cover and drill 4x holes for mounting. I used some nylon 1/4" diameter spacers from the hardware store to press down on the original heat plate. I had to cut these down to .67" long. I also had to pick up some longer (1.5") #4 screws on eBay for about $6. I then applied some thermal compound and installed the heat sink. I will attach relevant photos in the event anyone else wants to try this.

I’ve had it installed now for about 30 minutes and the heat sink is about room temp. The top of the Tablo is slightly warm.

If any issues develop, I will post them here.