The key for Dish DVR's if airflow
UNDER the DVR. I use very inexpensive plastic coasters for chair legs by gluing one on top of the other and then placing them under each of the four feet. This should be done no matter where the DVR is placed because in my experience it can make a great difference.
As for the Joeys: they get HOT, but they have lots of fairly big ventilation slits AND they don't seem to exhibit any unreliable behavior that can be attributed to the heat produced by the Joey. Any unreliability at a Joey has always been software or some internal defect in my experience. So, I don't see a case for attempting to do anything to cool a Joey. Joey's get really hot, but that is what they do and should still work well. Just leave plenty of room for heat to escape the Joey and outside air for flow around it. I would not put a Joey in a cabinet, but put it OUTSIDE the cabinet, even if out of sight behind or beside the cabinet on the floor even so that heat can escape the Joey. Joey's are not as delicate as the DVR with its precious (and heat producing) HDD that should be protected from even vibrations. I would not bother with a laptop for a Joey since you can put that thing almost anywhere where the heat can escape.
As for enclosed spaces such as cabinets or the like, Dish or TiVo Roamio DVR's placed in an enclosed space will NEED extra cooling, otherwise the H3 will exhibit unreliable behavior and the speed of the fan will greatly increase making a lot of noise desperately trying to cool itself. I lived through that. If the fan is in high speed, then it is TOO HOT and will NEVER get the DVR cool enough for reliable service. Putting a full-size, but inexpensive laptop under the H3 solves all heat related problems, and is an easy, cheap, but highly effective solution for any DVR.
As for the TiVo Roamios: the Roamios are notorious for its poor air flow and under-powered fan, and this can cause the fan to increase speed and produce noise and possibly exceed the temperature of its operating range. All manner of costly and time-consuming and trouble-some
(for me, disconnecting, removing, and replacing and reconnecting the DVR in the stack is the MOST difficult of the entire notion of cracking open the DVR just for a cooling solution) DYI's for fan replacement are discussed and done by those with plenty of time on their hands, but nothing is more simple and, yet, still highly effective as just slipping a full size laptop fan to do the same job. All done in a matter of SECONDS and no additional cost, back breaking removals from stacks and hard to reach electrical outlets (USP's) nor mess of a work bench, and never missing a recording either.
Yes, connecting the fans to the USB's of each DVR USB port has worked fine for MANY YEARS, and is often the ONLY place left to get power for the fans. I believe both the H3 and Roamio USB's were designed to power low load devices, so their presence connected to USB for power has never been an issue for either DVR over the MANY YEARS.
A laptop fan is an easy, rational, elegant solution for DVR's that are in need of additional cooling, so long as the DVR is capable of powering the fan, and most LATER model DVR's are designed to providing modest power for "future" devices by the DVR company. The laptop fan need not fancy or expensive. It should be of approximate size so that the all or the at least the great majority of the DVR can rest upon it providing airflow over most of the botton of the DVR.
While some prefer the longer, more expensive, and troublesome DYI internal fan replacement of a TiVo Roamio, a fair number of TiVo Roamio owners have opted for the laptop fan solution and are pleased with it, including yours truly. Now, a DYI to exchange an HDD for a new one or a bigger one is worth the trouble, but not for merely providing additional cooling when a laptop fan can be slipped under the DVR in seconds.
As for the concern of dust, that is a fair concern, but hardly what it was decades ago. A great many modern devices and over time we have learned that while dust can contribute to heat being retained among other problems, it nonetheless proposes only a minimum of concern, while HEAT and the lack of airflow or the lack of fan cooling the device is the REAL and even IMMEDIATE killer, not the dust. I know of and even have devices that over the many, many years probably have a great deal of dust, even with the fan sucking out the heat and some of that dust, but continue to work just as well as day one some 10 years ago. In fact, attempting any dust removal from such dusty devices as an AVR--with their massive ventilation slits that allow huge amounts of dust and other fairly big things--can create more problems than it is supposed to solve, and even KILL the device. While there is a right and proper way to do it very delicately, I don't know anyone (people who do know and repair or design the things) who recommends any attempt at dust removial, unless it is an attempt to SAVE a malfunctioning or even dead device (like an AVR) with nothing to lose as a last attempt. The thinking on dust has evolved over the decades, and equipment has improved in that regard, as well. Techs today are just not all that troubled by it as they once were.
So, laptop fans are a great solution for whatever devices may require more cooling, and certainly NOT absurd. It may be absurd to NOT consider a laptop fan as an option
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