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Peter Vollan | 1 May 02:02

Re: NEC PC-8201A Collectable Portable Computer For Sale

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.

On Fri, 27 Apr 2007 09:49:05 -0700, John R. Hogerhuis
<jhoger@...>  
wrote:

> It could be worse... you could be collecting minicomputers or
> mainframes like a lot of the guys on the classic computing list.
>
> Space is one of the reasons I prefer vintage laptops.
>
> The weird thing about our community is that we actually *use* our
> vintage micros because they have advantages over modern derivatives.
>
> On the cc list, that one computer has some marginal utility benefit
> over another is entirely irrelevant.  Here, the issue is often raised
> :-)
>
> -- John.

--

-- 
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jwhitton | 1 May 03:23

Re: cleaning the case

> I've seen where others much more knowledgeable than I have used the term
> "outgassing" - i.e. the chemical breakdown of the plastic itself, thereby
> changing it's properties into something much less useful. I'd hazard a
> guess that during this chemical breakdown, the plastic emits some form of
> gas, but that'd be a SWAG on my part. ;-)
>

'Outgassing' normally refers to the release of various volatile (usually
organic) solvents that are associated with the manufacture or coating of
plastics. While most of us think of plastics as being non-absorbent, most
*do* have a degree of absorbency, and will retain some of the above
mentioned substances. Over time, the stuff will 'evaporate',... sometimes
re-depositing itself on other surfaces, not unusually, windows. At any rate,
that's the reason that plastics 'smell' more when they are new than when
they have aged.

As an aside, many of us that have been around for awhile have had the
occasion to dye nylon. Think nylon doesn't absorb water? Actually, it
absorbs it pretty well. It was not uncommon to custom dye printed circuit
board latches..., enabling one to identify a card in a card cage by the
color of the nylon latches. Method? Simple.., bring a stainless steel pot of
water to boil, dump in plain old RIT dye (color of choice), dump in nylon
bits....., stir, ..... periodically checking to see if they are 'done'. I've
done this many times to produce other nylon bits in the color of my
choice..., nylon trim screws, etc.,  Nylon is not alone, of course. Many, if
not all,  plastics are somewhat absorbent, I've had moderate success with
Delrin. I guess it's worth mentioning that there is nylon..., and then there
is nylon.., various varieties..., so as I sink into an OT abyss, I'll ask if
anyone recalls the Remington 'Nylon 66' and knows why it was so named?
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Daryl Tester | 1 May 03:27
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Re: cleaning the case

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Ron Wiesen wrote:

> Mike H Stein wrote:

>> Yellowing is due to a change in the plastic's chemistry, which in turn is
>> caused by heat, sunlight, fluorescent lighting and the oxygen in the air,
>> depending on which explanation you choose.

> All are factors that contribute to the chemical change.  Methinks
> ultra-violet light (present in substantial amount with fluorescent lighting)
> is a heavy contributor.

So I guess lacquering the case won't prevent further yellowing?

--

-- 
Regards,
  Daryl Tester
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Steve Adolph | 1 May 03:39

Re: cleaning the case

metals outgas as well.  Particularly, gold plating can outgas-- hermtically 
sealed device packages with gold plating can accumulate outgassed hydrogen 
inside the hermetic package.

I once worked on root cause analysis for a GaAs chip that died while in 
sevice for about a year.  Hydrogen gas migrated into the gate metal of the 
FET and killed the device (the particulars of this mechanism were pretty 
amazing, involving the piezo electric nature of GaAs, and the formation of 
metal hydride in the gate, expanding the gate).  The hydrogen came out of 
gold plating on the ceramic package.

and this has nothing to do with cleaning the case!  sorry for the hijack.

jwhitton <jwhitton@...> said:

> > I've seen where others much more knowledgeable than I have used the term
> > "outgassing" - i.e. the chemical breakdown of the plastic itself, thereby
> > changing it's properties into something much less useful. I'd hazard a
> > guess that during this chemical breakdown, the plastic emits some form of
> > gas, but that'd be a SWAG on my part. ;-)
> >
> 
> 
> 'Outgassing' normally refers to the release of various volatile (usually
> organic) solvents that are associated with the manufacture or coating of
> plastics. While most of us think of plastics as being non-absorbent, most
> *do* have a degree of absorbency, and will retain some of the above
> mentioned substances. Over time, the stuff will 'evaporate',... sometimes
> re-depositing itself on other surfaces, not unusually, windows. At any rate,
> that's the reason that plastics 'smell' more when they are new than when
(Continue reading)

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Rick Hanson | 1 May 06:16

Re: cleaning the case

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At 06:27 PM 4/30/2007, Daryl Tester wrote:
>So I guess lacquering the case won't prevent further yellowing?

Easy on the lacquer ... it might just melt the case.  However, you 
could use enamel and paint the case yellow so when it yellows you 
won't know it.  -Rick- 

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Ole Göbel | 1 May 09:27
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Re: cleaning the case

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>
> Easy on the lacquer ... it might just melt the case.  However, you
> could use enamel and paint the case yellow so when it yellows you
> won't know it.  -Rick-

Thank you Rick, I guess that's what I will do. But first get it white
for better adhesion, so it seems that soap water is a good begin. I
don't know what Fantastik is. But then the next question is how to
open the lid of a T200? There are now screws so I guess I have to
press onto some magic spots?
Sorry for blaming smokers for having yellowed my labtop, in fact I
didn't know where the color came from. But fact is that the whole
machine smells like a cold ashtray, so I assumed that there was a
yellowish layer of smoke on the plastic, having exactly the same color
as cigarette filters.
Ole
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PETERSON, JAMES P | 1 May 13:44
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RE: NEC PC-8201A Collectable Portable Computer For Sale

Hmm...

In hindsight, it's probably a good thing I didn't win the sealed-bid auction
for the DEC PDP-8 our computer science classroom had in high school. IIRC
the winning bid was $20. We were using Apple ]['s by then, and were using
the PDP-8 as a space heater for the CS lab. Turn it on, feel the heat.

What I really wanted from the auction, though, was a nixie tube scientific
calculator the size of a typewriter. Didn't win that, either.

Jim

-----Original Message-----
From: Rick Hanson [mailto:rick@...] 
Sent: Saturday, April 28, 2007 2:49 AM
To: m100@...; m100@...
Subject: Re: NEC PC-8201A Collectable Portable Computer For Sale

At 09:49 AM 4/27/2007, John R. Hogerhuis wrote:
>It could be worse... you could be collecting minicomputers or 
>mainframes like a lot of the guys on the classic computing list.

Hmmm... I am reminded that back in the early '80s I once owned a BTI 3000.
It was a gimmie from Golden Gate University, i.e., they were upgrading to an
HP 3000 and I was given the opportunity to haul the old BTI away.  One of my
teaching contracts was for GGU back in those days.

I recall that my buddy and I did not have the boot strap so we called BTI.
They sent out a field tech who locked us out of the room so he could
secretly key in the boot strap (in octal).  After he left we stepped through
(Continue reading)

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M H Stein | 1 May 14:49

RE: cleaning the case


----------
From: 	jwhitton[SMTP:jwhitton@...]
Sent: 	Tuesday, May 01, 2007 10:16 AM
To: 	m100@...
Subject: 	Re: cleaning the case

> Sorry for blaming smokers for having yellowed my labtop, in fact I
> didn't know where the color came from. But fact is that the whole
> machine smells like a cold ashtray, so I assumed that there was a
> yellowish layer of smoke on the plastic, having exactly the same color
> as cigarette filters.

Check for the faint odor of whiskey........, it probably belonged to a
newspaper journalist. I can picture the guy in a seedy hotel with an open
half-empty bottle, a glass, a cigarette dangling from his lips and an
overflowing ashtray sitting next to the computer.... feverishly writing his
report on ...., what?.... maybe the '85 fight between Larry Holmes and
"Bonecrusher" Smith....

;-)

John.

----------------------
LOL!

You forgot to mention the floozy on the bed mumbling, "howzabout 'nother
drink, sugar?"...
(Continue reading)

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jwhitton | 1 May 15:16

Re: cleaning the case

> Sorry for blaming smokers for having yellowed my labtop, in fact I
> didn't know where the color came from. But fact is that the whole
> machine smells like a cold ashtray, so I assumed that there was a
> yellowish layer of smoke on the plastic, having exactly the same color
> as cigarette filters.

Check for the faint odor of whiskey........, it probably belonged to a
newspaper journalist. I can picture the guy in a seedy hotel with an open
half-empty bottle, a glass, a cigarette dangling from his lips and an
overflowing ashtray sitting next to the computer.... feverishly writing his
report on ...., what?.... maybe the '85 fight between Larry Holmes and
"Bonecrusher" Smith....

;-)

John.
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Rick Hanson | 1 May 17:14

Re: cleaning the case

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At 12:27 AM 5/1/2007, Ole Göbel wrote:
Thank you Rick, I guess that's what I will do. 
But first get it white for better adhesion, so it 
seems that soap water is a good begin. I don't 
know what Fantastik is. But then the next 
question is how to open the lid of a T200? There 
are now screws so I guess I have to press onto some magic spots?

There are tricks to opening the case on a Model 200.  Here is a brief summery.

Flip the system over, turn off the MEMORY POWER 
and remove the four case screws.

Flip the system right-side-up.

Open the lid.  In the middle under the LCD is a 
4"ish wide cover.  Push in on the top where it 
addresses the LCD and pry down ... be careful not 
to mar the plastic.  You should be able to do the 
above with just your fingers ... yes, it will 
hurt like heck but do not use a sledge hammer and crowbar ... that's not cool!

With the cover off use two hands (and your left 
foot and then hold your head sideways) to pop the 
ribbon cable out of the LCD-side connector.

Press in on the middle-edges of the top case half 
to "pop" the little plastic case holders and remove the case halves.
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Gmane