Cool-It/Cool-Plate Equipment Coolers (1 Viewer)

[Marc Alexander]

As my Kenwood VR-2090 has gotten older, it has become more sensitive to heat. The symptom displays itself as a clicking in the speakers when the IR remote is used. I have relieved the problem somewhat by moving the center and rears to an external amp (unfortunately - no pre-outs for L and R). I am looking for a solution to help keep this receiver cool.
The only thing I have found are these equipment coolers at Smarthome. The price seems a bit steep. Any opinon on these? Is there another solution I am missing?

 

[Chu Gai]

well I still don't see why you consider the problem heat related. myself, i'd consider putting in a small fan to increase the ventilation. on those units, i'm unclear how they work but regardless, they'll also be creating at least as much heat as cold. so where does the heat go?

 

[Saurav]

on those units, i'm unclear how they work but regardless, they'll also be creating at least as much heat as cold. so where does the heat go?

Um... they're metal plates with a bunch of CPU fans connected to a wallwart power supply. There are close-up pictures on the lower right side of the page which show this pretty clearly. How much time did you spend looking at the link? You shouldn't let your scepticism get the better of your thoroughness
Marc,
To answer your question - I think you could easily do what Chu suggested - just hook up a single fan to an appropriate power supply, that should make a big difference from what you have now. Do you need to pay $200-$300 to have 6 fans on top of your amp? I don't think so, but you're the best judge of that.
And yes, another thing that Chu said - are you sure the problem is heat related?

 

[Saurav]

On a side note, it's interesting how human perception works. One person could take a cursory look over something and say "sure, that makes sense", without poking the idea further to see if it held up to logical scrutiny. In exactly the same way, someone else could also take a cursory look over something and say "nah, that's all nonsense", again without taking the time to dig deeper into it to find out what it really is.
Apparently, cynics and sceptics can have their biases and pre-concieved notions too, just like other gullible people

 

[Marc Alexander]

Well, I found a place where I can get the cool-it for about $120. I'm pretty sure the problem is heat related. There are no problems if I take and leave the cover off of the receiver. There is a built in fan but it seems to be controlled by volume level (-20 dB seems to be the threshold, normal listening for me is between -31 and -27 dB) and not temperature. I will try hardwiring the internal fan first (not easy to get to), it does a great job cooling the unit when it runs. I have the service manual and am fairly technical.

I am seriously looking at the cool-it for asthetic purposes. Some makeshift cooler should work fine, but will look out of place.

 

[Saurav]

I will try hardwiring the internal fan first (not easy to get to), it does a great job cooling the unit when it runs.

It'll probably have a resistor in series with it to limit the amount of current flowing through it. You should be able to find the value of this resistor by following the schematic in the service manual. I would recommend against hooking it up directly to the power supply, as that might fry the fan.
I've heard of people increasing the value of that resistor to reduce the voltage drop across the fan, apparently this makes them turn more slowly. In some cases, this makes the fan significantly quieter, while still retaining most of the benefits of forced air cooling. Or maybe they put a suitably rated diode in series, which effectively sent half the voltage cycle to the fan. Hmm... I don't remember any more.

 

[Marc Alexander]

Well, after doing a little exploratory surgery and perusing the service manual, it turns out the fan is working as designed. However, the design for fan control is poor IMO. The fan has two speeds. Slow kicks on at 65 degrees C and fast at 105C, much too hot IMO. The speed is controlled by two thermoswitches.

The fan design itself is very good IMO, there is a tunnel right down the center gut (a little to the right) of the receiver past heat sinks which are attached to PC boards (along the top and sides of the fan tunnel). The power supply is isolated far away from any boards to the left.

I believe I've found my solution. I plan to hardwire the 65C switch closed. This should keep the fan on at slow speed whenever the receiver is on. It will also allow the 105C to still up the speed to fast if temp should ever get that high. I can always go back and hardwire the 105C. Now I just have to find these since they are seperate mini-boards and I've had not located them physically or on the exploded view in the service manual.

Hopefully, I won't fry the receiver!

 

[Marc Alexander]

105C is damn hot! I thought about closing the 105C switch and letting the 65C operate normally. However, the schematics seem to reveal that the 65C turns the fan on and off and the 105C controls speed (slow/fast).

Its too late tonight for me to try it (I've learned that lesson the hard way). Hopefully this will solve my problem, and it won't have cost me a penny!

 

[Chu Gai]

Saurav: I looked at all the pictures, read the manual, etc., regretfully though on a quite old 15" monitor as the 19" was out for repair as a result the images did not appear all that detailed. I'd thought that those might not be plates, but also function as heat removal in which case, in a limited space environement, heat would've been dissipated quite close to anything that happened to be on top. There wasn't a whole lot of information in the ad nor in the manual. Yet my stating I was unclear about it, is hardly skeptical, its is merely a question. Not once did I suggest it was bogus or that I was skeptical of its ability to cool off a unit yet your second post suggested as much. I consider that a pretty cheap shot.

While heat may exacerbate the problem seen when using your remote, a possible reason may be a defective solder joint, perhaps on the IR receiving module. If Marc's handy and so inclined to take a chance, it might be of interest to tap around that area with a non conductive object which may point to a permanent solution such as redoing the solder joint. That's his call though.

 

[Saurav]

You said:

yet your second post suggested as much. I consider that a pretty cheap shot.

I apologize.

 

[Chu Gai]

My backup monitor has quite a large dot pitch and is there to provide rudimentary use. I won't get into the other issues it has in the ways of image quality. The picture on an associate's monitor is quite better. Let us forget the apology and chalk it up to misunderstanding. Looking at the picture though, I wonder how much noise is generated from the 6 fans. Hopefully its not like some of the fans i've heard in computers.

 

[Saurav]

Looking at the picture though, I wonder how much noise is generated from the 6 fans. Hopefully its not like some of the fans i've heard in computers.

LOL That's a good point, those fans can make their own music very easily

 

[Marc Alexander]

Well...I tried hardwiring the thermoswitches...no luck. It appears as these are not simple switches but some sort of transistors. I was not able to force the fan on by opening or shorting any switch connections. In fact, shorting the trigger lead either of the other two leads (both grounds) sends the receiver right into protection mode!

After examining the exhaust vent on the back of the unit, it looks to be perfect for mounting a 3.5" case fan (screw holes and everything). I think this will be the best solution. Now I just have to find a very quiet fan (you have to put your ear right next to the receiver hear the built in fan...it is virtually silent). I don't plan to spend any money on the cool-it.

 

[SanfordL]

Hey Marc, does the amp have heat fins on the top? I am not aware of your unit, but it may or may not. The reason I am asking is, if you have heat fins, you can create a closed loop water pumping device to run over the fins. I brew beer, and it's how I cool my wort down before pitching. Not too certain how comfortable you'd be with H2O running over your electronics, but if something went wrong, you have a perfect excuse to upgrade.

Basically how I've thought about doing this is to buy that fairly thin copper tubing available at whatever home repair store you frequent. Then, you'd just use a round metal form to bend the matrix you are creating. Next, find a water pump that can take the constant work, but won't be loud. Not too certain if a car water pump would work, but it might if you know how to convert from 12 volt. Then, just make a cooling tower of copper tubing which would be wrapped around a drinking glass for bending (don't want the water heating itself back up - hence the tower shape.) Just attach the tubing, place the cooling tower and the pump outside your cabinet, and you are ready to roll.

I saw a guy who did this in his car to cool down the fins on 4 V12 Alpine's, but he had the 12volt power source, making the job easier. Never had a leak though, but I didn't ask him if he needed to change the H2O out, or else how he kept it from growing Sea Monkey's in there.

Just a thought, and might not be too good of one, but if anyone makes this, please send me some pictures.

 

[Marc Alexander]

no heat fins on the exterior...this is a Home Theater Receiver. There are some heat syncs internal but what your describing is not something I would even consider doing (it makes for an interesting story though).

 

[Marc Alexander]

While heat may exacerbate the problem seen when using your remote, a possible reason may be a defective solder joint, perhaps on the IR receiving module.

I believe I know what the source of the problem is. Kenwood has another design flaw...the LEDs for front display are held to the board only by solder on the backside-through relatively large holes. I've had this receiver serviced before and it seems that when you take apart the front display it is inevetable to put pressure on these LEDs when putting it back together. The Kenwood has a two-way remote and an LED which is supposed to come on whenever there is IR Rx or Tx. The LED never worked after service but I didn't care because it was annoying and I prefer it off. The clicking sound didn't develop until long after the service so I never made the connection. Pressure on this LED has actually lifted the pad and a portion of the trace off of the board. There is no easy way to address this as there is now no more pad to solder to. I will talk to a technition to see if it is possible to repair the trace and replace the pad. If so, I still need to find a way to stabilize the LED.