Being driven by a desire to expand functionality and mitigate temperature concerns, I have successfully migrated necessary components from a Dell Optiplex 390 DT from its originally case to a full size ATX case that was from the first computer I built years ago! What I started, thinking it would be a simple task, was tedious, meticulous and potentially hazardous to my equipment. Here’s what needed to happen to make it function properly.
DISCLAIMER: I am not responsible for anything in your life. Do what you do and don’t blame me for anything. This is for informational purposes only. I am not a manufacturer, engineer, work for Dell or even have any credentials to show that I might know what I’m doing. Use this information at your own risk and ALWAYS confirm everything personally because assumptions are the mother of all mistakes.
The motherboard is a Dell M5DCD. I found information on the web about the 5 wire pinout for the power button and bi-color LED harness with 6 pin connector (one cut and used as key). P/N 085DX6 I spliced in the new case’s momentary contact power switch to the appropriate leads. I found the information
here. A diagram was located at
this page. I can confirm that pins 1 and 5 (yellow and red) are shorted together. They both lead to negative (-) / ground (common). So the yellow was negative (-) / ground (common) and the black was positive (+) 5VDC. Shorting them brings the voltage low enough to cause PSON (power supply on). I actually disassembled the power button and used just the interior portion to replace the original green power LED, making sure not to push it in far enough to depress the switch. This may have just been luck. So the bi-color LED shows through to indicate power/failure state.
The HDD LED was a challenge. After quite a bit of time scouring the web and getting nowhere, I disassembled the front panel I/O assembly and removed the diagnostic/HDD LED assembly. After testing for voltage, resistance and continuity, I managed to get the HDD LED on the case working by splicing in the negative (-) / ground (common) wire to the
green HDD lead going to the second pin in from the corner nearest the center of the motherboard. Merely going to any negative (-) / ground (common) left the light illuminated constantly rather than with disk activity. I then spliced the positive wire for the new HDD LED into the
red VCC lead, which seemed to regulate the voltage sent through to all of the LEDs on the LED PCB. I accessed the wires by sliding the boot at the end toward the connector and scribed the jacket a couple of inches, then opened it up and pulled out the two wires that I cut, stripped and soldered to the leads going to the new LED. I stuffed everything but the heat shrink covered solder joints back into the jacket, pulled the boot back over the end and taped it all up with electrical tape, letting the new leads hang out. I didn’t want to chance doing any damage to components trying to solder at the connector or LED PCB.
Dell’s pinouts on the USB and AUDIO headers have all of the grounds shorted together with additional wiring inside the I/O panel assembly, connecting all of the grounded pins and wires at the ports. The front panel, with audio, USB and diagnostic/HDD LEDs, was used as the proprietary pinouts made it much easier to use them to avoid more wire tracing and avoid the front panel I/O cable failure error on boot. I’m sure I could have used the original equipment but I liked knowing the Dell ports were newer and would definitely work without modification. I used a “blank” from one of the 5.25” bays to achieve a clean and functional appearance by drilling and carving holes to accommodate the ports protruding from the panel assembly. I had a separate HDD LED on the case front panel so I opted not to allow the HDD or diagnostic LEDs to show through but I may drill holes for the diagnostic ones later and use the original film with the numbers to cover the holes. I simply hot glued the assembly without the metal bracket to the back of the blank plate, after cutting it down to fit. I centered the USB and audio ports on the plate. I must admit, it turned out really clean looking aside from some scratches.
The toughest part was getting everything to be “happy” and not receive any errors or diagnostic LED readouts on boot because that would affect the overall voltage to the HDD activity indicator LED, causing it to not function as expected. I had also originally tried using the single color LED for power but wanted the bi-color for detecting a fault state since I opted not to drill holes for those to shine through. Since voltage was always present going to either leg of the bi-color LED, either power lead caused the power LED to stay illuminated regardless of state. So I got crafty and managed to squeeze the guts of the power button, which contained all the wire leads and the bi-color LED, into the opening for the original LED. Winning...
After a serious, long lasting headache and lots of testing, I concluded that the original power supply used a standard ATX 2.x 24 pin connector layout and color coding. I had to make sure even though it SEEMED to be standard because I am using a standard 12V ATX 600 Watt power supply to power everything in this case, which includes a 120mm constant power chassis fan, the original SYS_FAN1 from the Optiplex 390 DT case, the CPU fan, a 3.5” SATA HDD, two 5.25” SATA DVD-RW/DL optical drives, the front panel I/O assembly consisting of two USB 2.0 ports, a 3.5mm headphone jack, a 3.5mm microphone jack and diagnostic/HDD LEDs, a four port PCIe USB 3.0 with UASP SATA power connector, USB devices from keyboard to to wireless adapter and everything else on the board that gets power through the ATX power connector. I plan on adding at least one SSD and, hopefully, a redundant SATA HDD, which would cause me to ditch one of the optical drives. I left the FDD installed but not connected as it uses PATA and there are no IDE ports on this main board. If I had to, I could have the signal converted but I’m good for now.
I moved the internal speaker over to the new case as well.
I didn’t connect the reset switch and didn’t see a connector on the board so decided to omit it.
I plugged in the chassis intrusion switch but haven’t mounted it yet as I never use it and keep it disabled in the BIOS.
It was definitely a serious undertaking but I am completely satisfied with the end result. Plus, this gives my mother something to be sentimental about since this was the case that I used for my very first PC build for her.
This beautiful Antec Sonata case has become my frankenputer!
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