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Sharp PC-6220

Twospruces

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Dec 9, 2009
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Any thoughts about this machine? There is one for sale locally and at first in was keen. 12MHz, compact, AT, internal HDD. But...it has one of those connor 20MB drives. And no floppy.

I'm thinking an XT CF card might be really hard to accomplish.

Getting files in and out is via serial cable. Ouch.

Am I looking at this correctly?

Thx
 

modem7

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Melbourne, Australia
Any thoughts about this machine? There is one for sale locally and at first in was keen. 12MHz, compact, AT, internal HDD. But...it has one of those connor 20MB drives. And no floppy.
Some info at [here] and [here].

I'm thinking an XT CF card might be really hard to accomplish.
From what I see/read, you would need the optional expansion unit to host it.

Getting files in and out is via serial cable. Ouch.
Also, a parallel port.
 

Twospruces

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thanks, appreciate the note. That system connector sounds promising. need a pinout! Guess I need to download that service manual.
 

Twospruces

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So, I could not resist, and I picked up this non-functional PC-6220.
And yes it was certainly non functional. The Nicd battery pack was just a mess and done for.

Some nice surprises:
* it came with an external FDD, so that helps to transfer files
* it was fully intact, just not working

Or course, I tore into it to find the issue. And.. I did.
The PSU needed to be recapped. It was a real learning experience. Under my microscope, all of the surface mount electrolytic caps had beads of fluid on their pins, and some of the pins were quite corroded.

Anyhow, I found enough parts in my various bins to get the nasty caps swapped, et voila! A perfectly fine PC-6220.

Best of all, I found the service manual for 6$ online. and I have what I need to make an XT-CF adaptation.

Other nice surprises:
* what a nice piece of compact engineering! very impressive
* the old Connor 20MB disk is working fine. Quite loud though. I wonder if that means imminent death.
* the LCD is really super nice and readable - which is why I ultimately wanted it as an improvement over my Zenith Z-171.

So, stage 1 success.
stage2 = add 80C287 and a homemade nimh batt pack
stage3 = design a clever XT-CF adaptation (and get away from that loud spinning disk
 

Twospruces

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I must say I am really thrilled with this ultra compact AT machine!

It is all working great. Added an 80287 chip also. I'm using it to develop an algorithm in Turbo C.

All in all, an excellent compactly engineered machine. Really very nice. I'm not going to bother with adding a CF card until I have to. The Prarietek 120 is spinning away just fine as it is.

There are only a few threads here on this machine. I can only assume there weren't many sold. They were quite pricey at the time.

Anyhow, now with the schematic available, the power supply fix is pretty straight forward. Other machines may be saveable.
 

Twospruces

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I see that I never really finished this story. So this cool little laptop had an 80287 socket... should have been an easy upgrade right?

So I bought an IIT 80287 compatible chip off ebay. With excitement I plugged it in... no go! Why??!?!!

Luckily I have a scope and a schematic.
So I dig in. Turns out one of the signals between cpu and 80287 was open circuit! Shock.

I can't see any board defects to explain the open circuit. So, I bodge wire it up. To my general surprise that fixes the issue! I wonder if I just got really unlucky and had a board defect, or was this a design issue?

End result a nice compact fully equipped pc-6220. I still think this is a great example of a low power compact design. Reminds me of the evolution path that the trs80 m100 to tandy 200 could have been.
 
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