Hot T2

[fangios]

Hi all,

My T2 runs extremely hot. It is so hot that I could almost burn myself on it. I am running a Toshiba 1GB drive in it.

Any suggestions?

[prl]

Is any part of the case particularly hot?

What height is the HDD?

[sub3R]

... Any suggestions?

If you have a temperature probe, take a temperature measurement of the area that you think feels hot. I was concerned about the temperature of the tuners in our T2 after feeling how hot the F to PAL coax adaptors were on both tuner inputs. But even though the tuners felt quite hot to touch, tuner A only measured 51ºC with the ambient temperature at the time around 24ºC. The tuner cases were hotter than the F to PAL coax adaptors.

The tuners were much hotter than the 1TB Hitachi HDD which felt barely warm to the touch when it was running. I would class that HDD as running cool.

Make sure you have plenty of space for ventilation all around the T2 & preferably not in in enclosed cabinet unless it is very well ventilated top & bottom. Air flow from the bottom to the top through the T2 is essential.

I also did away with the T2’s rubber feet that continually fell off, & replaced these with slightly higher feet. These may not improve air flow much but at least they stay stuck. I used Pro-Tec Madico 7/8" (22mm) self-stick 23268 black surface protectors ($3.90) at Bunnings. Stick these on a flat surface beside where the original feet are attached.

[fangios]

Thanks for your fast replies.

It does sit in an enclosed cabinet, which houses my Yamaha amp, and Sharp Blu Ray player. Although it is enclosed it is quite a large space in there, and have run my previous Beyonwiz DP without issue for 10 years.

The T2 is sitting directly on the Bluray player, which is generally on standby only and not warm at all.

The hottest parts are yes, directly above the tuners, and the whole underneath is very hot also.

The feet have also now fallen off (I assume because of the extreme heat) so I will have to come up with something else to sit it on that won't self combust!!

The drive height - well it is approximately level with the top of the 2 rails that it bolts to, does that help?

Unfortunately I don't have a temperature probe.

[IanB]

If you unplug the antenna connector and leave the unit on for 10 minutes, does the temperature of the tuner cool?

The early T3's had an issue with putting unlimited current +5Volts onto the antenna connectors, this would dramatically over heat the tuner whenever a dc short circuit antenna cable was connected.

So far the T2's and T4's have never exhibited the problem, but your unit might have an issue.

The tuners do get somewhat warm in normal operation. Can you temporarily put your T2 out in the open to see how it fairs without any enclosure related air flow restrictions.

[sub3R]

... The hottest parts are yes, directly above the tuners, and the whole underneath is very hot also.

The feet have also now fallen off (I assume because of the extreme heat) so I will have to come up with something else to sit it on that won't self combust!! ...

Being in an enclosed cupboard with a Yamaha amp is a concern (I assume you are using this with the T2), my Yamaha RX-V3900 runs quite warm & I would expect it to increase the temperature inside an enclosed cabinet considerably (I have it sitting on top of the cabinet). The T2 I took the temperature measurements of also sits on top of a cabinet.

If you don’t have any feet on your T2 then that could be why it is running warm/hot, you won’t be getting any air flowing into the bottom of the case. I recommend getting some stick-on feet the same as or similar to what I mentioned in my previous post.

I can confirm that the bottom of our T2 case is also quite warm to touch around the location of the tuners. I would like to see more or larger ventilation slots in that area.

Without temperature measurements it is difficult to say if your T2 is running hotter than normal. If you can touch & keep your fingers on your tuner PAL inputs then I would say it is normal, even though they feel warm.

Your HDD height is similar to mine so that height would be ok.

Just to clarify; the original feet on our T2 didn’t fall off due to high temperature, I found two sitting in the bottom of the box the T2 was packed in. I think they are just poor quality because all 4 feet kept falling off every time I moved the T2 even after cleaning the T2’s surface with isopropyl alcohol. If the new feet I fitted ever fall off I intend to clean off the self-stick glue & re-attach the feet with something like Selleys silicone sealant.

I used a thermocouple attached to a digital multimeter to take the temperature measurements. If you are still concerned about the temperature & you have a digital multimeter, a thermocouple to suit the multimeter isn’t that expensive.

But definitely do the test that IanB suggested.

[sub3R]

If you unplug the antenna connector and leave the unit on for 10 minutes, does the temperature of the tuner cool?

The early T3's had an issue with putting unlimited current +5Volts onto the antenna connectors, this would dramatically over heat the tuner whenever a dc short circuit antenna cable was connected.

I must do that test with mine when I get a chance.

From memory my tuner temps didn’t feel much different from when I had our old VHF/UHF antenna & capacitor isolated PAL wall socket compared to the new VHF antenna with F connector non-isolated wall socket.

[sub3R]

... I must do that test with mine when I get a chance. ...

Hardly any difference in tuner temperature with both antenna inputs & both 75ohm terminators connected to A & B tuners compared to having both antenna inputs & both 75ohm terminators removed.

The below figures were taken with the T2 in standby, with the top cover removed, & a constant 22ºC ambient temperature, so they are for comparison only.

Top of tuner A case (vertically mounted tuner):

• Immediately after removing the T2’s top cover = 50ºC (both antenna inputs & both 75ohm terminators still connected).
• 20 minutes after removing the T2’s top cover = 46ºC (antenna inputs & 75ohm terminators still connected). The temperature had stabilised at this. At this 20 minute mark I removed both tuner’s antenna inputs & 75ohm terminators.
• 30 minutes after removing the T2’s top cover = 46ºC (both tuner’s antenna inputs & 75ohm terminators had been removed for 10 minutes). The temperature stabilised at this.

Top of tuner B (horizontally mounted tuner) was 2ºC cooler than tuner A.

Top of the PCB approx 5mm in front of tuner B measured approx 2ºC hotter than tuner A (approx 4ºC hotter than the top of tuner B case).

I didn’t measure it but the PCB is about 5mm from the bottom of the T2’s case so most of the heat at the bottom of the case would be coming from the PCB (heat being transferred to the PCB from the tuners, U26 (LM1085 ADJ) regulator chip, & U25 (LM1117C 3.3) regulator chip).

For reference, I’m not using any antenna loop through in the above. Antenna feed for this PVR; coax input to a band-pass filter > powered adjustable splitter > separate inputs to tuner A & tuner B. A 75ohm terminator on each tuner output. USB tuner still connected.

PC board details: IN-M422DT, Ver: 1.1, 2015.01.19
Tuner A: Samsung DNOQ44QAV109A
Tuner B: Samsung DNOD44QZH102A

Edited for clarification.

[IanB]

For reference the original T3 problem was no current limit to the +5V supplied to the antenna socket.

Plugging in a capacitor isolated cable was no problem.

Plugging in a 75 ohm terminator would draw 67mA. Okay, an extra 0.33 Watts.

Plugging in a dc short circuit cable, draws 2 to 3 amps, Cooks the tuner and the coax cable and the coil in the external splitter. Problem!



Yes the 40C to 50C tuner case temperature is higher than I personally would have designed for but is pretty typical of all T2, T3 and T4 tuners without any positive air flow.

Even the most gentle of drafts can reduce the temperature quite a lot. i.e. a small 12v fan running on only 2.5 volts reduced T3 tuner temperatures to 28C.

[sub3R]

... Even the most gentle of drafts can reduce the temperature quite a lot. i.e. a small 12v fan running on only 2.5 volts reduced T3 tuner temperatures to 28C.

I also noticed that, I wouldn’t like to have the T2 in an enclosed cabinet without forced ventilation. The NE sea breeze (slight at the time) we get coming through the window dropped the temperature of the tuners a couple of degrees when I opened the window. Fitting a fan would be good but at this stage I’m not sure where to fit it (the T2 is on display for all to see on top of a cupboard).

I expect the 50ºC I measured immediately after removing the T2’s top cover may have been 51ºC or a bit more (at 22ºC ambient). The case of the tuner starts to drop in temperature fairly quickly once the T2’s case cover is removed & it took a few seconds to tape the thermocouple to the tuner’s case.

The temperature of the motherboard is a bit of a concern, it was too hot to keep my fingers on the board. It may drop the temp a bit if there were heat sinks on the regulator chips which contribute to the temp of the board. The board is being used as a heat sink.

I’m in two minds about having the 75ohm terminators on the tuner outputs, I don’t know if there is any advantage on a receiver (vs. transmitter).

Thanks for the other info you supplied, all good information.

[prl]

...
I’m in two minds about having the 75ohm terminators on the tuner outputs, I don’t know if there is any advantage on a receiver (vs. transmitter).
...

If the pass-through is buffered (and I think it is), there's no point in terminating the tuner outputs.

Even if the pass-through is a splitter, I doubt that having the output terminated would do much. Having it may even lower the power available on the splitter output into the tuner.

[sub3R]

I wasn’t sure if it was buffered or not. I’m not too concerned about the splitter output power reduction if that is a possibility, I’m feeding each tuner from an external adjustable powered splitter (Kingray SA164F).

However small it may be, I’m more concerned about keeping the tuner’s & regulator’s current down to reduce heat. I’ll have to do some line current measurements to see if anything is obvious.

[Paul_oz53]

Don't have a T2 but if cooling is a concern, has anyone tried sitting one on a laptop cooling pad?

They appear to be cheap and usb powered. Would seem to be an easy way to test the cooling effect. However, noise and blue lighting may be problems for regular use.

[sub3R]

I hadn’t thought of a laptop cooling pad. If one was available that was a suitable size & the LEDs could be isolated then that could be the answer for fangios.

For myself, I was thinking of making a skirt out of aluminium the same width & depth as the T2 with an internal lip around the top to support the T2 on its rubber feet. The height would need to be high enough for the mounting of a good quality 120mm fan speed adjusted so it would be quiet when running.

The fan would blow air up through the vent holes in the bottom of the T2 case & the skirt would have plenty of vent holes or a partial cut-out along the back so the fan could draw in fresh air. A removable filter could be made for the fan to filter dust. The skirt would be powder coated black to match the T2.

Should be easy to make & if made correctly would look part of the T2. Something else to go on my things to do list.

[sub3R]

... However small it may be, I’m more concerned about keeping the tuner’s & regulator’s current down to reduce heat. I’ll have to do some line current measurements to see if anything is obvious.

I can’t see any difference in the 12V DC supply current with or without the 75ohm terminators fitted to both A & B tuner outputs.

For the record; with the T2 switched OFF the 12V DC supply to the T2 measures 12.38V & under load it measures 12.2V.

• In standby with the HDD still spinning & without anything being recorded I measured 0.836A with & without the terminators fitted.
• In standby without the HDD spinning & without anything being recorded I measured 0.812A with & without the terminators fitted.
• In live TV with 3 services on 3 different channels being recorded (3 tuners used) I measured between 1.084A & 1.167A (fluctuates up & down between these two figures) with & without the terminators fitted.
• In standby with 3 services on 3 different channels being recorded (3 tuners used) I measured between 0.999A & 1.002A (fluctuates up & down between these two figures) with & without the terminators fitted.

So the terminators aren’t adding any measurable load & therefore heat so they may as well stay on.

HDD is a Hitachi Travelstar 2.5" 1TB 5K1000 (HTS541010A9E680) 0J22413 5400rpm HDD.
HDMI out to TV.
Ethernet LAN.

[prl]

...
So the terminators aren’t adding any measurable load & therefore heat so they may as well stay on.
...

They may not be adding any significant power supply load, but depending on exactly how feedthrough works, they may be reducing the available input signal power. Since you're using a powered splitter to fed them individually, that may not matter, even if they do.

[sub3R]

True. If I ever go back to a feed through setup I’ll take them off. And if I ever get any signal breakup I’ll experiment with & without.

[Brainz]

Don't have a T2 but if cooling is a concern, has anyone tried sitting one on a laptop cooling pad?

They appear to be cheap and usb powered. Would seem to be an easy way to test the cooling effect. However, noise and blue lighting may be problems for regular use.

I live in Brisbane in a unit which can be an oven in summer. It was consistently 30C + over this summer. In fact it is 29C as I type this.
I am currently using a Deepcool N19 I purchased a couple of months ago from Umart for $12 to cool my T2.
It is reasonably quiet and the LED light actually lets me know the box is on more easily than the red one. It also has a pass-through so you won't lose a USB port. I have the T2 offset to allow the fan to cool the tuner components. The temperatures although not measured are noticably cooler around the tuner portion of the casing.
When I decide where the box will live permanently I'll be able to cool the power supply as well as the bluey USB tuner.