Elite Mini and POST Error 901 - Solution

[Eismeer]

I started getting this message after installing the second m2 disk.
Instead of installing a case cooler (useless in this situation), I decided to cheat the diagnostic system. And with the money saved, install passive cooling for the M.2 disks.

Chassis FANCPU FAN

[SDH]

EDIT: I've read that your error message gets generated only if you have a 65W processor plus 2 M.2 drives installed.

Your pictures are showing two fan connectors... the 4-pin CPU cooler header located up by the CPU socket for the heatsink/fan there (but not currently installed), and a 5-pin header for an extra fan that is not installed (nor do you plan to install one). Not sure what the PWM pinouts of those two headers are, and how you chose your single wire jumper. I'm sure you had some good logic for that jumper's placement.

However, why not do what HP advises? That is shown below on the label stuck to the top of the two heat spreaders for the two M.2 drives that can be installed, shown below. In the motherboard picture no M.2 drives are yet installed:

Kit = 13L70AAMotherboard with your 2 fan headers in yellow

Those little Mini boxes can get hot, and HP took that into account. The 13L70AA kit is easy to find via google, and it is meant to add two things... an accessory cooling fan (for two M.2 SSDs just below the fan) plus for a single 2.5" SATA SSD (just above the fan). You don't need to install a SATA SSD to use the fan part of that kit... the fan has its own independent power cable with 4 wires (standard PWM but a non-standard fan plug end). The black fan plug end goes onto the black motherboard 5-pin header, and the central motherboard header's pin is not used by the fan. You can see the 4 total metal connectors on either side of the unused central pin hole (which does not have a wire attached to it).

This way you get HP engineered cooling as intended by the engineers. If I wanted to do a ghetto mod I'd just mount in one of those fans and make sure it came with the necessary fan plug end and proper wiring, shown below. However, this kit is easily available and not that expensive. I'd tape the blue-ended ribbon cable atop the nearby black metal surface... it is for a 2.5" SATA SSD if you wanted one of those too.

The ''kit'' without SSD

The kit's plug end and pinout

View from below:

[Eismeer]

The 13L70AA kit is a universal solution, universal is not very good. This kit simply drives air around the case, it does not touch the SSD drives.
Without this kit, I have 15-17mm of space in height to install good passive cooling.

I simply routed the tachometer signal to both connectors.

[DGroves]

HP took the time to determine that a supplemental cooling solution was required for the sec M.2 ssd on this compact system your comment that all the sec fan does is move air around and does nothing useful and is therefore useless and not required is shortsighted

HP most likely determined that there was indeed a dead air location where the sec ssd is located and  added a fan to prevent that, by allowing the air to circulate in this area the sec ssd is properly cooled and this area's heated air can now be exhausted properly by the systems main cooling fan

i'm sure that if HP was able to keep the system properly cooled just by doing what you did they would have not have spent the time engineering the kit they currently offer and simply made a single wire with the plugs on both ends to achieve the same as your soldering did

the heat output of various ssd's can vary greatly,.. your mod/hack can most likely work with most non performance based ssd's but i suspect that high end ssd's (even with a heatsink) might still get heat soaked due to no airflow in the area and throttle or have heat related issues

[Eismeer]

I disagree with you. I wrote above "a universal solution is not an ideal solution".
The HP solution is only suitable for working with regular SSDs. You will not have enough space to install a high-performance SSD with a radiator and a 13L70AA kit.

If HP's kit was like this, I'd buy it!

HP 5188-8004

[DGroves]

hp's solution does cool the are where the sec  storage device is located and allows proper device operation over HP's stated temp range with optional devices installed and used at max capacity

your solution simply adds a larger thermal mass that takes more time to become heat soaked and reach the same temp as the device without the heatsink most likely

  passive heatsinks REQUIRE airflow to cool them,  and if there is no air movement then there is no cooling happening on a passively cooled device long term

Edit:  you will not need to install a high-performance SSD with a thick radiator when using a 13L70AA kit.

however you can add thin copper shim to the ssd's controller chip in most cases, 

 however this is not necessary in hp's opinion when using one of their approved storage devices and their cooling kit

I'm not saying your hack won't work in some environments, but if i personally was using that device in a location that was not climate controlled or had a 65watt cpu dual storage devices and running a program that stressed the cpu and/or storage devices then i'd personally opt for the HP cooling solution but as i said that's just my preference it's your system so you have the last say on what's done to it and you control things like cup stress and area cooling for the device so your mod may be perfectly suitable for your usage

[SDH]

Eismeer,

Thanks for your help on the pinouts. My guess is that your new picture of the black accessory fan header on your motherboard was based on probing the pins with a multimeter or oscilloscope. If so then you are showing what you measured, and the middle pin there is truly not used because it is 12VDC. The fan is 5VDC instead, as shown on the fan's label. So your pinout is correct and 12VDC never is seen by that fan.

I've found the HP Spares Part Number for the fan alone (L93623-001) with added pics shown below. You can now go to eBay and get the right fan with the correct plug end using that part number and also see more details from real examples. Also, look up on eBay HP M.2 heatsinks. You'll see some pretty low profile nice HP heatsinks, and there are many others out there. I'm hoping this will encourage a respected Ghetto Modder I know on the forum to design a standoff plate/L93623-001 fan holder that could mount where the HP full kit would normally, and put this popular topic to bed.

EDIT: Be careful. I've seen a search for that part number result in some eBay results that show a similar AVC fan with a different HP part number on a label on the fan and also showing a black 4-pin-hole plug end rather than the necessary 5-pin-hole plug end with the proper non-use of the middle hole. I'd be sure to communicate clearly with the seller on this purchase, especially if from China.

Another option would be to just get the whole kit, unscrew the fan from the bottom and screw it to the top in the place where the 2.5" SSD would have gone. Now you have the proper fan, a nice mount, and free space beneath the kit for your M.2 heatsinks. EDIT: Thinking about it a bit more... the fan is blowing downwards onto the area the 2 M.2 SSDs would be. Unscrewing the fan from its normal position below the metal mount and screwing it right back on from above the metal will mean it still blows downwards, but from about 1/2" higher. You'd still be able to use the same 3 fan screw mounting holes and the fan lead will still reach its motherboard header easily. Fan mounted from below:

Kit from belowFan only from aboveFan only from below

[SDH]

Same mini, different HP forum segment:

elite mini 800 g9 bluetooth - HP Support Community - 9405573

[SDH]

Here's what I believe I'd do.

1. I'd buy one of these from eBay... Proof of concept. Search for "HP Elitedesk G3 Mini 2.5" HHD Caddy with Fan 914256-001 Tested" and filter for lowest cost. You'll find these... one pic to show this earlier caddy version came with the fan mounted above rather than below the metal parts (with the fan still blowing downwards). That top cross plate rotates upwards for easy access to that screw under there, and note there is a big open space for airflow:

2. The white 4-hole fan plug shown above is not what you need to work with the black motherboard accessory fan header discussed higher in this thread. You also will need to buy the correct fan with the correct 5-hole black plug end that also is available via eBay. It is still a 4-wire fan cable but does not use the central 12VDC pin present on the header.

I even found the metal caddy on eBay without the wrong fan/plug end for $12.00 USD including shipping... HP seems to be using very similar metal caddys for multiple generations of the Mini PCs.

3. Both of your 2280 M.2 drives will benefit from an attached heatsink. There are both HP and aftermarket skinny form factor heatsinks that won't interfere with the close side-by-side positioning needed in these Mini PCs.