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foone, 11 months ago to random

So my roommate bought that weird Hand386 portable PC that popped up on aliexpress. Let's tear it down (nondestructively for once, since I'm borrowing it).

#hand386 #teardown

foone, 11 months ago

So over by the USB port, we've got a CH375B.
This is an 8-bit IO chip for USB, specifically for storage.
(it's also an 8051-based core! there's always an 8051)

foone, 11 months ago

There's three 74HC139s, which are dual 2-to-4 line decoders.

This maybe is used for wiring up one of the expansion ports to the ISA bus?

foone, 11 months ago

A YAC512-M. This is a DAC used by the OPL3 to create the analog output of the audio chip.

foone, 11 months ago

A PAM8403 three-watt class-D stereo audio amplifier.

foone, 11 months ago

Assorted power regulation/charging circuitry that I'm not going to go into.

foone, 11 months ago

though I do want to show off this amazing bodge job.

foone, 11 months ago

So the keyboard PCB is also the display converter PCB. It stars a Realtek RTD2660, which is a standard video controller. It takes in analog video and drives LVDS displays with it. It's an all-in-one chip that's used on a bunch of cheap monitors, and it's also an 8051!

foone, 11 months ago

Next to it we've got a P25Q40H half-megabyte serial flash chip. This is presumably used to store configuration info for the RTD2660.

foone, 11 months ago

The other chip on the keyboard/video board is an HM82C42. I can't find any info on this specific version, but it's almost certainly an Intel MCS-48 acting as a PS/2 keyboard controller.

foone, 11 months ago

The keyboard is a rubber membrane onto the PCB, like a remote control. It's functional but feels pretty crap.

image/png

foone, 11 months ago

that large connector on the side is called "ISA" on the PCB.

foone, 11 months ago

It's a 60 pin connector. 8-bit ISA is 62 pins, 16-bit ISA is 98 pins.

So if they just merged some grounds, 60-pins is totally doable.

foone, 11 months ago

The other connector is 12 pins:
This one is PS/2 and VGA. An adapter is included with the device.

foone, 11 months ago

Storage is on a 2 gigabyte CF card. It's got Dos 7.1, Windows 95, and a few games pre-installed on it, plus a driver for the CH375 USB storage chip

foone, 11 months ago

Games included:
Doom, Wolf3d, XianJian QiXia Zhuan (aka Chinese Paladin), Tyrian, Raptor: Call of the Shadows, and Uncharted Waters: New Horizons
Daikoukai Jidai II