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Discussion Starter · #1 · (Edited)
The Normal temp range for a Tivo 2 - Pioneer, Toshiba, Humax brand is between 35 C and 39 C degrees . And I live in Texas, 38 C (101 F) is a normal day.

What screws up the temperatures reported like 45 C or 47 C as normal is the case designs and the intended air flow path.

These early models came with feet of clay, literally.. the coaster sized standoffs they had for feet collapsed into whatever they stood on over a short period of years. Pioneers being the exception.

Pioneer used both firm solid feet, and had air vents on the Left and Right side of the cases.. so when the feet collapse they did not "block the air vents".

For the Toshiba and Humax branded models this was not the case. The feet collapsed covering the front air vents underneath the case and blocking the ability of the rear facing exhaust fan to pull clean cool air from the room into the case and over and under the mainboard and exhausting it out the back. This is not good.

To make matters worse, to protect my Tivos I placed a soft foam table mat between the stacked AV devices and this contributed to covering the vents and making the seal near air tight. Cleaning off the debris of the disintegrating clay feet just made the seal that much tighter.

I think this happened to a lot of people back in the day without realizing it and may have made Tivo 2's not last as long as they should have, heat contributes to a shorter hard drive life as well.

My solution was to go to Home Depot and buy some silicone gelly squares with self adhesive and place them next to where the clay feet pinion used to go."Clear Bumpers SKU 100698 by Everbuilt". They raise the body 3/4 of an inch off of wherever they stand and keep the air path open.

In my case my Tivo 2's immediately dropped from a bare minimum of 42 C down to 37 C right away and dip even lower if the air conditioner is on.

Replacing the fans on these models is challenging, WeekKnees and some places have drop in replacements. But I prefer to use the Noctuna NF-A6x35 FLX. Widely available.. but not extremely cheap or extremely expensive these are the same depth as the orignals, but only 60 mm not 70 mm fans. But the CFM airflow and the dBM noise levels far exceed that of the originals.

These are three-wire fans, but come with adapters for a PC molex, with fixed speed resistor adapters for Normal, Low and Ultra-low speeds, and a 150,000 hr MTB mean time between failure.. or about 7 years.

In my case it was a simple process of using the Molex connector provided with the fan to snag power from the DVD power connector and reconnect it.

The Molex provided is a dual sided Male and Female back to back adapter style which goes in-between the power cable and the original DVD socket.. so no extra special wiring is required.. its as close to a drop in adaptation as you can imagine.

And you can still explore the lower speeds with the Low and Ultra-low speed resistors. Even the "lowest" still produces more CFM and lower dBM than the original fan.

The temperature sensor is not a part of the original fan power connector and still works after tapping power this way.

The fan itself is 10 mm "smaller" than the original in the Toshiba and Humax branded Tivo 2's but I found wire tie wraps suitable temporary replacements for the mounting screws. The grill in the back has jagged edges which bite into the silicon noise reduction mount points of the Noctua design.

The wire tire wraps also allow centering the Noctua label side of the fan on the center dias of the "Raised" fan vents on the back of the case.. so there is the least disruption to air flow possible.

Longer term.. or I would have bought them before replacing the fan with the Noctua.. is a 60 mm to 70 mm fan adapter, which is simply a ring with mounting holes for a 60 mm fan and a 70 mm fan so the mounting screws for each have something to bite into when they are put back into the back of the chassis. They basically look like a gasket for a cylindrical object with the thickness for screws to bite.

I used to wonder why they used an Exhaust fan (a push method) as opposed to an Intake fan to cool the interior. But this arrangement makes sense to me now.

Stacked AV gear usually all exhaust hot air out the back of their cases.. because of this convention.. any odd man out.. that has an intake fan on the backside.. would be inhaling the hot air exhausted out the back of another AV component.. and to make matters worse.. hot air rises quickly rather than spreading out as it rises.. so it would channel the hottest gases into the intake fans of a component stacked on top.. which is already the farthest unit from the floor where it might have better cooling.

This same effect would take place no matter if the intake fan were in the front or zigzagged back and forth.

The best is one convention which is to exhaust all hot air out the back and let it rise.. and pull in fresh cool air from the larger room in the front. This does bring the potential of picking up dust from the air.. but is far less of an immediate problem than inhaling hot air from the back.

Also its rather non-intuitive.. but pulling in air from under the front lip of the case means its dragged just slightly under the case giving any dust a chance to be snagged by a deliberate strip of filter material.. or as a result of gravity.. before actually being pulled up and into the case.

And the point of entry on these units is at the bottom of the main circuit board and underneath the power supply.. so dust has to actually travel around to the top side in order to deposit on chips and other parts. This maximizes the gravity filter effect.. with no filter material to clean out on a regular basis.. dust collecting underneath the outside of the case becomes more likely.

This dynamic totally changes if the bottom vents are blocked.. in that case air "seeps" in due to the vacuum effect of the exhaust fan from any seams or corners of the sides of the case.. and maximizes the potential for depositing dust on top of the circuit board and components.
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