An Amazing Find for My Next Project -- iMac G4 20"

[ersterhernd]

Thanks Leopold, it's a treat to actually sit down and enjoy using it now!


Cheers!

 

[ersterhernd]

Oh Ohhhhhh, still a few minor artifacts popping around the LCD...


Problem solving mode again, I guess.


EDIT: Next morning it's all good again, wow this is puzzling...


Ersterhernd

 

[ersterhernd]

Build Log Update -- Major Change to the Project

Anyone who's read this entire thread has likely seen that about 2 weeks ago I ran into a major problem in this build. The i5 Haswell / HD 5000 D54250WYK NUC upon installation threw thousands of red pixel artifacts onto the LCD. I spent over two weeks focused on fixing this issue. It was completely unexpected because the extensive tests I did with one of my i3 NUC units prior to purchasing the D54250WYK show zero issues of any kind.

After literally pulling my hair out trying to solve the screen corruption, I came to a dead end. I'm resolved that its a hardware incompatibility with the new i5 and my rewired 20" LCD. Although I made many changes to wiring, grounding, shielding and even gamma levels in OSX; all of which improved the issue immensely from it's first appearance, the artifacts always began to slowly re-appear after a period of use. This instability may be solved in subsequent releases of OSX, I'm not sure. Windows 7 on the D54250WYK rendered perfectly on the iMac display in all tests, however, it's not an option to use permanently on this system.

I decided a couple of days ago that enough was enough. I have handled and re-handled the delicate TMDS wires from the iMac neck, to the point where I'm concerned about damaging them. It was time to solve the issue and get the iMac 20" build done with 100% stability.

I put both my 17" and 20" iMac builds side-by-side on my work counter. I ran an HDMI cable from one to the other to test the operability of OSX on the opposite monitor. The i3 NUC was run through the 20" LCD and the new i5 NUC was run through the 17" LCD. Extensive tests were done on both, and proved that they were perfect candidates for a simple 'swap' of NUC's into the other build.



The Intel i3 NUC (in foreground) connected to the 20" iMac LCD (closest to wall ) via a longer HDMI extension cable. It performed absolutely flawlessly.

The tests proved that the problematic HD 5000 graphics could be cleanly run on the 17" LCD, and the HD 4000 graphics performed without issue on the 20" LCD. It was evident that although this would force a deviation from my initial goals for this build, at least the problem could be fixed and the 20" iMac could be brought to stability levels within my expectations for a successful build.

I engineered a hardware 'swap' between the two iMacs (17 and 20) that is easily reversible if a solution is ever found for running HD 5000 graphics over the iMac 20" LCD. The wiring is very similar in both builds, so the NUC's are fairly portable in that regard. Unfortunately I lose USB 3.0 functionality downgraded to USB 2.0 because of the wiring in the 17", but I can live with that.


The D54250WYK i5 NUC installed into the 17" iMac

The DC3217IYE i3 NUC installed into the 20" iMac

The issues are solved from what I can tell. Both the 17" and 20" iMacs now have perfect video graphical rendering on the LCD's of each. I realize this wasn't a perfect solution, but was the best I could come up with after weeks of struggling to fix the artifacting issue that I never expected with the new NUC.

At this point in time, I cannot recommend the D54250WYK for the 20" iMac G4 build. Until such time as the graphical inconsistency is worked out, it's a much safer bet to utilize the DC3217IYE instead. Although not as feature-rich as the new NUC, it works flawlessly on the 20" screen, even through smaller HDMI cables that the new NUC totally failed on.

Hopefully these graphical conflicts can get ironed out, as the new i5 NUC HD 5000 is a terrific unit in all respects. Unfortunately, I wasn't successful in achieving stability with it on the 20" LCD, despite extensive efforts to find the solution.

That said, the iMac G4 20" is a beautiful machine to mod, and is a pleasure to operate using the previous generation of Intel NUC. Highly recommended for those interested in this classic.


Regards,

Ersterhernd

 

[ersterhernd]

Updated Final Hardware Summary

After the hardware 'swap' to achieve graphics stability (discussed in my previous post), this is the final feature set of the 20" iMac G4. I've tested it fully stable for 24 hours at this point.

- Intel NUC DC3217IYE with i3 processor @ 1.8 GHz
- Speed Stepping from 800 MHz to 1.8 GHz
- Sleep and Rewake fully operational
- 8 GB 1600 DDR3 RAM
- 256 GB mSATA Crucial SSD Storage
- Apple A1181 Bluetooth
- Broadcom N Series WiFi utilizing original iMac G4 antennas
- Internal 19V Antec SNP90 Power Brick (90W)
- Internal PicoPSU WI-25-120 PSU
- 12V to 24V Step-Up converter to obtain 24V
- BC547B Transistor actuated PicoPSU on/off control
- Picaxe 08M2 Micro-Controller for touch-sensor LCD brightness control
- Picaxe 08M2 Micro-Controller for pulsing sleep LED
- Picaxe 08M2 Micro-Controller for PWM case fan control
- Startech HDMI to DVI converter with MOLEX PN 74320-4004 connector
- Noctua NF-B9 92mm Case Fan with software PWM speed control
- StarTech ICUSBAUDIO Stereo Audio Adapter
- 3.5mm Audio Jack
- Original iMac G4 speakers via external 20W amplifier
- 3 x USB 2.0 external port
- Gigabit Ethernet port
- Original AC Power Plug and internal AC filter
- Original Power Button
- Hard Reset button
- Apple BT Trackpad & Apple Wired Keyboard



Ersterhernd

 

[minihack]

Updated Final Hardware Summary

After the hardware 'swap' to achieve graphics stability (discussed in my previous post), this is the final feature set of the 20" iMac G4. I've tested it fully stable for 24 hours at this point.

- Intel NUC DC3217IYE with i3 processor @ 1.8 GHz
- Speed Stepping from 800 MHz to 1.8 GHz
- Sleep and Rewake fully operational
- 8 GB 1600 DDR3 RAM
- 256 GB mSATA Crucial SSD Storage
- Apple A1181 Bluetooth
- Broadcom N Series WiFi utilizing original iMac G4 antennas
- Internal 19V Antec SNP90 Power Brick (90W)
- Internal PicoPSU WI-25-120 PSU
- 12V to 24V Step-Up converter to obtain 24V
- BC547B Transistor actuated PicoPSU on/off control
- Picaxe 08M2 Micro-Controller for touch-sensor LCD brightness control
- Picaxe 08M2 Micro-Controller for pulsing sleep LED
- Picaxe 08M2 Micro-Controller for PWM case fan control
- Startech HDMI to DVI converter with MOLEX PN 74320-4004 connector
- Noctua NF-B9 92mm Case Fan with software PWM speed control
- StarTech ICUSBAUDIO Stereo Audio Adapter
- 3.5mm Audio Jack
- Original iMac G4 speakers via external 20W amplifier
- 3 x USB 2.0 external port
- Gigabit Ethernet port
- Original AC Power Plug and internal AC filter
- Original Power Button
- Hard Reset button
- Apple BT Trackpad & Apple Wired Keyboard



Ersterhernd

Great build E.

It is a shame you had to swap out the NUCs, but I know the feeling.

My own iMac g3 mod would not run OSX through the MacBook Pro Retina screen using my Zotac H87 board - but it would run Windows - while if I connected a lower resolution screen than the MBPro the H87 was fine too.

Brilliant modding though.

 

[rick26]

Great job E!

Too bad the i5 Nuc gave you graphic problems..

But switching the Nuc's is a great solution, at least by switching them it wasn't for nothing

Really enjoy all your work E!

Rick,

 

[ersterhernd]

Great build E.

It is a shame you had to swap out the NUCs, but I know the feeling.

My own iMac g3 mod would not run OSX through the MacBook Pro Retina screen using my Zotac H87 board - but it would run Windows - while if I connected a lower resolution screen than the MBPro the H87 was fine too.

Brilliant modding though.

Thx for the positive comments minihack! I see that you had a similar experience. Pushing the envelope with the marriage of new and old hardware sometimes brings surprises, as we've both found out.

Its never a slam dunk with these mods, is it?


Cheers!

 

[ersterhernd]

Great job E!

Too bad the i5 Nuc gave you graphic problems..

But switching the Nuc's is a great solution, at least by switching them it wasn't for nothing

Really enjoy all your work E!

Rick,

Hey thanks Rick! Looking fwd to seeing your iMac build begin...



Cheers!

 

[ersterhernd]

The lighting is poor on this image, but the two iMac's 17 and 20 are shown side by side in my office. I'm very happy with the outcome of the project, despite the fact I had to switch the NUC's around. The lower keyboard and trackpad control the 17".

Ersterhernd

 

[mrdale]

Bravo. Nice to have these issues investigated and resolved before I really begin work on mine.