PQNG #2

Continuing a bit with the Pqng project, I constructed a second unit for Melwyn in return for making the software. I had been thinking about a desktop model and as Melwyn preferred it over a wall-mount one I decided to give it a spin. Besides the power supply (stripped from a DVD player), the hardware is the same as before.

Pqng2, assembly frame

Modified assembly frame with the CPU and backlight transformer installed.

The “desktop model” is simply equipped with a stand that keeps the unit in a upright position. I decided to test integrating the power connector to the stand.. with proper insulation added of course.

Pqng2, stand

Support stand

Pqng2, stand & PSU

PSU connector mounted to support stand

If the power connector was mounted to the unit itself, it could be easily converted to a wall-mount model. This would require reorganizing the sub-component layout as there really isn’t room for the connector in the current one.

Pqng2, rear view of assembled unit

Rear view of assembled unit.

Pqng2, PSU close-up

PSU connector

Pqng2, reset switch

Reset switch soldered directly to CPU module.

I decided to test “bundling up” the floppy cable by cutting it to smaller stripes and wrapping them together with some twist ties. Apparently, this a mod some computer geeks use to make the cables less wide so that when installed inside a computer, they cables don’t obstruct airflow as much :)

Pqng2, side view

Side view of completed unit.

Pqng2, first boot

First boot..

Adding some kind of a boot-time display turn-on control would definitely make Pqng more ‘classy’ in a way. So to say, to prevent the bootup screens (BIOS etc.) from appearing on-screen. Probably the easiest option would be to add a simple RC time circuit to the +12VDC backlight inverter power supply. This could turn the backlight on, say, 20 seconds after power-up.

Pqng2, complete

..and off it goes!

Other than that, the floppy drive is becoming the biggest downside of Pqng design. It’s simply too unreliable and oversized in regard to other sub-modules. No idea what to use instead.

I have tried testing a selection CF-cards of different brands/sizes with no luck; the CPU module refused to detected them (or wrongly detected the size). The CPU does have a Disk-On-Chip socket, but these chips are way too expensive for this (and likely any) project. Not sure if something else could be shoehorned to the socket though..?

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  1. The return of PQNG « My Diy Blog - 28/04/2011

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