"One Perfect Part at a Time"

Killer Heat

I operate three PC type computers in my workshop and each controls a separate CNC machine. I have two Taig CNC mills and a home brew (HB2) CNC gantry router. Two of the computers are refurbished., small form factor size. I paid no more than $100 for each of them. One is an HP Compaq and the other is labeled a Compaq. Their styles are different. The third is very similar but larger bare bones built up. Probably $250 invested in it.

None of them have great internal cooling as they were designed to operate in conditioned spaces. My shop operates at outdoor temperature. It’s been running 95 degrees in there for the last two weeks. Outside it has been very near 100.

The larger case unit running the HB2 has stopped suddenly twice in the middle of a long run. It ruined one piece and almost ruined the re-run second.  It is not going to be put back into service again in this hot weather.

The HP-Compaq computer is a sweet little machine, or at least it was. I just let it upgrade from Windows 7 pro to Windows 10. I use it with a smooth stepper so I don’t have to be concerned about pulse timing. The upgrade took many hours of loading and saving files. It converted just fine and MACH3 and the Smooth Stepper were performing well with Win10.



I left it on for a day with it doing nothing but staying on the network. I wanted to see if WIN 10 was going to do any self-updating since the install. When I came back to it the computer was dead. There is a single blinking LED on the motherboard constantly flashing at about 1 Hz with a slight audible click.

I did a lot of investigation and it appears the Power Supply has become nearly powerless. It is making 5 volts and something around 4 volts but there is nothing higher. It could be the shop heat was too much for it. None of the internal fans will run and it doesn’t even think about doing a boot.

I ordered another refurbished $100 computer (not the same brand, it’s a micro format Dell desktop.) because at that price I probably can’t even purchase repair parts. It comes with Win 10 installed, a keyboard and a mouse. Perfect system for CNC control.

Power Supply

Power Supply

Actually, I did find a rebuilt PS online for $25.00 free shipping from a company called Server Supply. So maybe I can get the little PC back into operation. BTW a new PS was $136.00 dollars.

So it looks like CNCing will be off line until I get a cooler day, like 80 degrees. My next shop if I ever get one will be air conditioned! Ha!

4 Responses to Killer Heat

  • One of the benefits of running a manual machine shop (No CNC) is the hot weather wears down the human operator (me) but I know when to stop before I wreck a part! 🙂

  • The refurbished power supply was delivered today. It took about 15 minutes to pop it into the computer and plug in the cables. Everything is modular in the PC so there are no screws. Components just clip into place. A really efficient design. Power on and I am back in business.

    I had to do a total setup of the bootrom so there was perhaps another 15 minutes of setting defaults. Piece of cake. Windows 10 booted and everything was perfect. Totally a full restoration. All fans (there are three) are working and I set up the idle speed on the CPU fan a couple of notches just to help a bit. A tiny bit of internal fan noise is no issue in the workshop.

    If PS failure doesn’t become a habit, I think I still have a wonderful small form factor PC for the shop.

  • Wow! A double hit today. The Refurbished $100 computer showed up today too. It’s a Dell Optiplex 760 Ultra Small Form Factor. So small the power supply is a large external brick. 64 bit dual processor running slightly over 3.0 GHz., 2 Gig RAM and 170 Gig HD. Plenty for a CNC controller front end. It came with WIN10 installed. First impression it is a sweet little machine. It’s going on the HB2

  • I discovered a pitfall with using a refurbished computer for machine control in my workshop. It’s not a serious one. The on-board video on my little HP-Compaq is not compliant with running my Simplify3D software.

    The software will pop-up a warning that the video drivers are non-compliant with the version of the software. I would click it away and the software will continue to open.

    The screen looked normal and the program was doing what it should. Then I noticed there were a few features missing in the fancy display portions of the graphics. The graphics of the part being printed were ugly. A lot of detail was missing.

    The execution of the software was a good as it should be and only “pretty stuff” on the screen was messed up. I used the software several times with no problems in the actual printing.

    There is space on the computer motherboard for a video expansion card. I have ordered what I think is a proper card at a cost of about $50.00 with shipping. It will be nice to see proper looking video.

    This is certainly one of the reasons the computer was on the refurbished market. It works just fine with plain Jane document and office type operation but anything with fancy graphics will be designed for the newest features available at the time.

    Windows 10 is a stickler for needing a video upgrade. My main office computer required a video card replacement for win10 comparability. The shop computer did not. Strange. But now it has stumbled on its video when I fed it some demanding graphic tasks.

    This is also the machine where the power supply failed. One of the cooling fans had been placed in the case backwards. Probably when the dust was blow out for the refurbish.

    So the machine has needed some additional investment to keep it running. So far it hasn’t been that bad as far as I am concerned. It is still a very good investment.

    The picture in the main article shows there are no accessory cards (yet) installed. The video card I selected is a low power fan-less card and draws about 17 watts. I’ll post a picture update when the video card is installed.

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