CPU Cooling (BIOS Approach) and Power Supply Replacement

[average_male]

I've read many posts on these forums about CPU cooling and Power Supply replacement options. I'll be going over what my finders were when it came to fixing and cooling my Kronos Gen 1 73 keyboard which had:

• 1) A very loud fan
  
  2) A bad power supply (system wouldn't boot as the stock ENO-1612 power supply powered on with the POWER_GOOD reporting 0 Volts [should be +5V]).

I purchased:

• 1) A Noctua NF-A8-FLX fan ~$15
  
  2) A Seasonic 300SUB power supply (https://seasonic.com/pub/media/pdf/indu ... 00-SUB.pdf) for my fix/upgrade at ~$63. I heard a lot of talk about people saying that they could use a non-stock power supply for a Kronos but never actually saw this documented on this forum or any other place, so this may open doors for others who don't want to spend $200++ on a power supply but rather $63 on a power supply that has Japanese capacitors and has better cooling and efficiency 80+ Bronze (wanted to go with the 250SUB, but they were disco.)
  
  Seasonic 300SUB Pin-Out Spec Sheet: https://drive.google.com/file/d/1NUuOHL ... sp=sharing
  
  3) As well as many bits and bobs from DigiKey for the power supply interface adapter.
  
  4) 1/2” Aluminum angle iron from Home Depot. ~$7 for 36” length

For the power supply, I built a custom wire interface/adapter (see installation picture below for more details) that would plug directly into the existing Kronos 14 PIN, 4 PIN and 2 PIN power connectors (this would give the option to use the stock ENO-1612 power supply without any modifications to the existing Kronos wiring harness.)

This power supply has its own fan and doesn't spin on until the load reaches 50% of capacity and given the Kronos ENO-1612 is a ~120 Watt power supply, this Seasonic 300 Watt power supply never needs to engage its internal fan as the Kronos doesn't require such loads, so the end result is a quiet power supply. So far, so good.

Now when it came to the stock Kronos fan, I originally placed the new Nauru’s fan on the SSD mount and didn't find it any quieter than the stock fan. Tried all the other suggestion about LNA and ULNA (low noise adapters, basically resisters to slow down the fan) and this too didn't produce any noticeable reduction in fan noise. So I then came across two settings in the Kronos' D510MO motherboard BIOS which controlled the fan speed.

- System Fan Control (When this is ENABLED, the system manages the Fan Speed, when DISABLED, the next setting is used for fan speed)




- System Fan Speed (Lets you specify the fan speed from 50% to 100% with 10% increments)



So I disabled the System Fan Control and set the fan speed to 50%, this was quiet but didn't seem to push enough air around, so I kept incrementing this setting, rebooting and checking until I found a good balance. I found that 70% was a good balance but ultimately went with 80% as the difference in noise wasn't even noticeable.

I found that the original placement of the fan didn't make sense. I did some additional poking around found that the Intel NM10 Chipset (see diagram below) which was adjacent to the CPU got VERY hot and figured it would make more sense to put the fan in a location where: 1) the components needed cooling 2) in the general area where the temperature sensor is actually located (in this case, the sensor is located on the left edge or the motherboard, next to the CPU.)

Here is the layout of the fan location I selected, noted below as "Current Mod". If I was to do it over, I would place the fan more towards the NK10 Chipset as noted in the "Optimal Mod" figure as it would cool the CPU, RAM (more so) as well as the NK10; in addition, the fan wouldn't be nested under the Kronos chassis flange as noted in the 'Installation' picture:




I built some fan mounts for the CPU using 1/2" aluminum angle iron I got from Home Depot:

[Just the fan mounting brackets on the CPU heatsink using 6-32 nuts/bolts sandwiching between heatsink fin plates]


[With Fan Mounted]


[Top View]


[Installation (prior to wire management and organization)]


[Seasonic Power Supply with adapter interface. Important: In the final installation, the power supply cover was screwed on the power supply with a cut out for power wires. The top cover is needed for cooling performance as it creates a cooling tunnel and has heat pads on the underside of the cover.]


And here are the cooling results:

[Just after start up, cool 31 degrees Celsius]


[After 5 hours of playing the Kronos, non-stop with Combi, drums, Karma... the works..., difference in color is result of difference in distance from cell phone camera to the screen, cool 38 degrees Celsius]


As far as the fan noise goes, it is hardly noticeable and 100% better than it was previously. And for the heat of the keyboard, after my 5 hour session, the chassis wasn't warm at all. This has been the case for the last couple of months I have used the Kronos. This mod and update may not be for everyone, but hope it may help someone who is looking to do something similar to address the loud fan noise and expensive power supply replacement.

(please excuse the missing images, Flickr hates me,)

[SKung]

Nice, that's a cooler where he needs to be, placing it next to harddrives instead of the cpu is absolutely nonsense.

Researched for a way to mount a cooler on the heatsink but never found a proper way.

Your solution looks very professional, but I don't think I could reproduce that with those screws in the heatsink.
Did you bend the aluminium by yourself?

Maybe I could make a foursquared frame with 4 holes from an aluminium plate with 4 holes and use metal glue to place it on the heatsink...

[average_male]

Nice, that's a cooler where he needs to be, placing it next to harddrives instead of the cpu is absolutely nonsense.

Researched for a way to mount a cooler on the heatsink but never found a proper way.

Your solution looks very professional, but I don't think I could reproduce that with those screws in the heatsink.
Did you bend the aluminium by yourself?

Maybe I could make a foursquared frame with 4 holes from an aluminium plate with 4 holes and use metal glue to place it on the heatsink...

No, the angled aluminum is from HD. And how to mount the fan also had me thinking for a bit. Here is what I did to make the fan mounting brackets.

I cut out two ~3” pieces off of the 36” aluminum stock piece. I then cut two 1/2” deep slices in a scrap 2x4 at a strategic distance from each other, placed those two pieces of cut aluminum into the cut slices in the 2x4. Using a 3” hole saw, I cut the two arch cutouts in the two aluminum pieces. This is what you see in the first picture for the air from the fan to move air through on to the CPU heatsink. I then measured and drilled 4 holes in each aluminum piece, 2 for the fan mount and 2 holes for mounting on the heat sink. Then I cut out the remaining interior of the arch pieces.

I also had to make a small wrench out of sheet metal to tighten the 6-32 nuts in between the heat sink fins. Worked out pretty well, was able to tighten the brackets pretty well. I wouldn't use any type of glue and that could get compromised with heating and cooling of the CPU/Fan and also subjected to vibration when moving or playing the Kronos.

[jones]

Nice, that's a cooler where he needs to be, placing it next to harddrives instead of the cpu is absolutely nonsense.

Researched for a way to mount a cooler on the heatsink but never found a proper way.

Your solution looks very professional, but I don't think I could reproduce that with those screws in the heatsink.
Did you bend the aluminium by yourself?

Maybe I could make a foursquared frame with 4 holes from an aluminium plate with 4 holes and use metal glue to place it on the heatsink...

No, the angled aluminum is from HD. And how to mount the fan also had me thinking for a bit. Here is what I did to make the fan mounting brackets.

I cut out two ~3” pieces off of the 36” aluminum stock piece. I then cut two 1/2” deep slices in a scrap 2x4 at a strategic distance from each other, placed those two pieces of cut aluminum into the cut slices in the 2x4. Using a 3” hole saw, I cut the two arch cutouts in the two aluminum pieces. This is what you see in the first picture for the air from the fan to move air through on to the CPU heatsink. I then measured and drilled 4 holes in each aluminum piece, 2 for the fan mount and 2 holes for mounting on the heat sink. Then I cut out the remaining interior of the arch pieces.

I also had to make a small wrench out of sheet metal to tighten the 6-32 nuts in between the heat sink fins. Worked out pretty well, was able to tighten the brackets pretty well. I wouldn't use any type of glue and that could get compromised with heating and cooling of the CPU/Fan and also subjected to vibration when moving or playing the Kronos.

Nice bit of fabrication work there. I notice you used nyloc nuts, they ain't coming loose in this lifetime.

The fan has dimples on the inside surface of the shroud, to mitigate noise from rotor tips.
Quite a bit of thought went into that fan design.

[average_male]

Nice bit of fabrication work there. I notice you used nyloc nuts, they ain't coming loose in this lifetime.

The fan has dimples on the inside surface of the shroud, to mitigate noise from rotor tips.
Quite a bit of thought went into that fan design.

I'm impressed, you noticed two very important details not noted. Nylon nuts were in fact used. Not sure how you determined this, guessing the tapper on the end of the nut? And Noctua really does a great job on their fan design. Seems you got an eye for design and detail.

[SeedyLee]

It's hard to believe that almost ten years after release, we are still finding new ways to improve the performance of the Kronos fan! Thanks for taking the time to write all that up.

I always assumed that the reason the fan was placed on the SSD cage was to provide airflow across the motherboard heatsink, SSDs and power supply. Is there any risk with the new fan location that the power supply could overheat for those users whose power supply doesn't have its own fan?

Fan control on the Kronos is a little strange - out of the factory, it's all handled in user space. I've found that adjusting the fan speed using the Linux driver results in all sorts of awful resonance with the non-stock fan, and I suspect this is due to the hardcoded PWM frequency that's compiled into the loadable kernel module. Changing it through the BIOS definitely seems like a good way to go to mitigate this (although a bit of a pain!)

I did play around with writing a daemon that can run on the Kronos and dynamically adjust CPU speed, but using that same Noctura fan on lower speeds actually resulted in more noise than running it at higher speeds

[average_male]

...
I always assumed that the reason the fan was placed on the SSD cage was to provide airflow across the motherboard heatsink, SSDs and power supply. Is there any risk with the new fan location that the power supply could overheat for those users whose power supply doesn't have its own fan?

My guess would be that the current fan location is not very effective in cooling the power supply. I checked the air flow and am hard pressed to believe that the stock fan size and location could be effective in cooling the power supply (and the CPU and motherboard components.) Also, given that the stock power supply is a fan-less design, this seems to imply that cooling is sufficient when in room temperature; The spec sheet for the stock ENO-1612 power supply just notes:

“14. POWER Derating Curve(at natural air-cooling)”

and graphs 100% Power Output at temperatures less than 50 degrees Celsius and starts to taper off from there when the power supply gets hotter.

Coupled with the temperature sensor location used by the Kronos system, which is located near the CPU, the placement and fan size is not going to get the system cooled where the Kronos’ sensor monitors system temperature.

I also sampled the various components, outside of the motherboard and found the other supporting daughter and i/o boards didn’t get hot.

For the SSD cooling question, my desktop computers have SSDs and there isn’t a dedicated fan to cool these SSDs, so I’d suspect this isn’t needed for the Kronos SSD. Assuming the Kronos just loads the needed samples/data once for a sound/set and doesn’t continuously read/write to the SSD after a sound/set is selected. This may be different when recording but won’t think the SSD gets hot and needs cooling.

So with that said, I’d say with a stock fan moved to be over the motherboard/CPU is a better cooling strategy as one should still get air circulation with in the case (perhaps the overall air circulation within the case would be less than stock location, but given my initial sampling of cooling requirements for other components, this shouldn’t be an issue as I assume that other Korg non-Kronos and non-Oasys systems don’t have fans for cooling those other components.)

[Stephen.m3]

Dear All,

Why Korg does not provide a cooling fan on top of the heat sink of the Processor. And a fan is installed by the side of SSD, good. But Processor gets much heated up. After few hours of work in Kronos we can feel the heat if we touch the right side panel of the Keyboard.

If we play open stage, it gets much heat. In Summer time heat increases.

Few say there is Fan Noise that we could hear, but a fan could have been provided with a medium speed on the top of the Processor heat sink.

In the previous Korg Kronos and Kronos X, it has a square shaped heat sink on the processor and I checked the Forum that, few have self installed a small fan on top of the head sink of D510/D525. Which reduces the temperature well. If we check the Global Mode, it has reduced the heat nearly to 50 % after self installing a fan on the Processor heat sink.

I use Kronos 2 which has a Asrock IMB-140D with Intel Atom D2550 Processor. Here the shape of the Processor Heat sink is different(Not a square shaped) and its not that easy task to self install a small fan on top of that.

Has any one tried installing a cooling fan for this processor. Or any alternate way !

Please Advise,
Thanks,
Stephen

[GregC]

not the answer you asked for, but a small external fan will help disperse chassis heat under extra warm conditions.

[Hector Space]

not the answer you asked for, but a small external fan will help disperse chassis heat under extra warm conditions.

Yes I’ve found this is an effective solution for a hot gig! I like to try and keep my K2 at or below 60 degrees as read from the Kronos system fan menu.

BTW the Kronos uses SSD streaming to play the majority of its pianos, so the SSD is quite busy reading into the ram buffer when you’re hammering that piano.

There is a difference between keeping the temperature of components below their maximum working value and running them at room temp. Basically continuous high temperature operation will shorten component life considerably. Whereas Korg maybe interested at keeping the cost down and a working life of over the extended warranty period in temperate climates, this in no way means the Kronos’ cooling system is optimal.

It does puzzle me why Korg needed to circumvent the built in bios fan controller. I can only think it’s coz they needed to make the fan run more quietly and felt the machine loading didn’t need the extra air flow???

This brings me to another fan related issue. Basically dust and keyboard key switch contacts do not make a happy marriage. So whoever thought placing a whole load of holes along the whole length of the Kronos and sticking a fan inside it was a good idea! Surely you don’t want the fan sucking in extra dust?
To me the way this should have been done is to use the case as massive heat exchanger. Certainly the K1 didn’t need a whole load of holes in the case. And possibly if the thermal coupling between the case and the PSU and CPU heat sink had been designed in the K2 wouldn’t need a fan at all!

[average_male]

Dear All,

Why Korg does not provide a cooling fan on top of the heat sink of the Processor. And a fan is installed by the side of SSD, good. But Processor gets much heated up. After few hours of work in Kronos we can feel the heat if we touch the right side panel of the Keyboard.

If we play open stage, it gets much heat. In Summer time heat increases.

Few say there is Fan Noise that we could hear, but a fan could have been provided with a medium speed on the top of the Processor heat sink.

I use Kronos 2 which has a Asrock IMB-140D with Intel Atom D2550 Processor. Here the shape of the Processor Heat sink is different(Not a square shaped) and its not that easy task to self install a small fan on top of that.

Has any one tried installing a cooling fan for this processor. Or any alternate way !

This should be doable using the approach outlined in the original post. You’d just need a different mounting bracket cutout and long bolts that’ll run through the heat sink to secure the brackets. And the brackets would have mounting holes for the fan.

The only unknown now is, what’s the motherboard’s option for allowing custom fan settings, not sure if it has similar setting as the K1 motherboard.

[Xenophile]

Reviving this thread to ask if any more people have attempted to upgrade the Kronos power supply, and if that upgrade improved reliability in terms of the dreaded “An error has been detected…” messages.

I routinely open up my Kronos 2-61 to re-seat the memory and other connections, as well as check for loose bits and pieces that might cause electric mayhem. But still the problem pops up periodically, and there does seem to be a correlation with certain venues, which to me seems to point to bad/noisy power distribution. We had a rehearsal last week, and my Kronos was repeatedly flaking out on me. I set it up at home, and have been running it continuously for days, and it has not thrown the error.

I bought a spare OEM power supply that I have yet to install. But I’m wondering if anyone can testify that an upgrade such as average_male describes actually improves reliability across venues with sketchy power.

I’ve tried using a UPS and a Furman rack-mount “power conditioner,” but I really don’t notice that there is any improvement in the flakiness. Of course the UPS saves the day in the event of a power failure, or someone accidentally-on-purpose kicking out your AC power cable. But it seems like these solutions don’t help if you’ve got noisy or glitchy power.

It’s getting to the point where I’m thinking about dumping Kronos from my gigging rig in favor of something more robust.