> Interestingly, that info implies that it's the steel strap
> around the perimeter of the CRT's face which does the implosion
> protection, and that the laminated faceplate is purely an
> additional protection against scratches etc.
Glass is very strong under compression but not strong under tension,
the forces on an unbanded CRT leave the glass on the outside edge of
the face under tension as the forces from the air pressure on the back
and the front of the envelope are concentrated there. The steel band
compresses the whole tube so that no part of the glass is under
tension.
That said I do have tubes that don't have this band but they are all
shallow angle tubes, much less than 60 degrees.
> So that article alone suggests that the faceplate isn't there
> to stop debris at all
The faceplate is there to stop debris, it really doesn't need to be
any thicker than the rest of the envelope but is made so that if the
envelope fails it will be inside the set that the failure happens.
Lee.
.
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Re: "I've seen an LED map light that plugs into and gets its power from USB.
It seemed to work OK."
That's nothing. Computer Geeks is selling a motorized USB "Aquarium" .... a
clear plastic "tank" in which motorized fish (or perhaps just a mural of
fish) move, powered from a USB port.
At 16:50 -0500 10/4/05, tony wrote:
> >
>> Drive *does* make spinning-up and head-seeking noises (once
>> per power-up). LED indicating drive attention does flash, *once*, as
>
>Does it sound as though it's staying spun-up? It doesn't make spin-down
>noises I hope.
Not until powered down, at which point it makes the noises I'd expect
(taking 2-3 times as long to spin down as the fan, for example).
>Those 'wings' are heatsink tabs, used to conduct heat away from the
>actual chip. It's a standard package for power driver type chips. I would
>guess this chip is either the spindle motor or head actuator driver.
Thought I was being clever, but Oh Well.
>As to whether it should get hot. Well, it is a power device, so it would
>get warm. But if it gets too hot to keep your finger on it for any length
>of time, then I'd start worrying. The chip may not be faulty of course,
>it might be a problem (like a shorted load, or an incorrect drive signal)
>elsewhere in the unit.
Both the head seek and the platter spin noises are consistent with
what I recall from before the failure, so I'll bet that chip is OK.
It's warm, but I can keep my finger on it for seconds at a time, with
no blisters arising.
Started looking for similar drives to mail-order for a controller board-swap.
Thanks to all responses so far!
Progress about to come to a screeching halt on the project, as I'm
about to hit the road again. Sigh.
--
- Mark
210-522-6025, temporary cell 240-375-2995
>From: "Vintage Computer Festival" <vcf at siconic.com>
>
>On Tue, 4 Oct 2005, Andreas Holz wrote:
>
>> I'm experiencing some monitors in the last time, mostly, but not only
>> from HP, with the effect of some kind of small bubbles or shell-like
>> failures in the flront part of the crt-tube. Somewhere I read the
>> description of "screen mold".
>
>Nowadays the consensus is leaning towards a delamination process.
>
>> Does someone knows this effect, has an explanation of it's source (is it
>> really temperature related?) or how to avoid this problem. Some of these
>> monitors (esp. of a HP9845) are looking so badly, that I don't dare to
>> power on.
>
>Most likely it is the protective cover over the CRT which is delaminating
>from the CRT face. I don't currently know of a way to prevent this. It
>seems to happen randomly.
>
Hi
I think it is from evaporation of plasticizers in the layer.
As they evaporate over time, the material shrinks. This causes
a void. The void provides another path for the plasticizer to
evaporate and a local stress point. This forms the stem like
channel feature. As time goes on, plasticizer evaporates from
the edges of the channels. This causes new stems to radiate
outward. This makes the typical fern leaf look.
I would guess the biggest difference between different
manufactures is either a different material or different
sealing of the edges.
The fogging of the material is most likely moisture from
the air.
Dwight
At 04:36 PM 10/3/05 -0700, you wrote:
>
>
>If the connector is gold plated, you should not need to clean them. If you
>are having green, then the gold is a very thin plate,
Not necessary. Gold is very porous and acids and the like penetrate it
easily and corrode the copper underneath and the corrosion products then
travel back through the gold and appear on the surface of the contact. It's
not uncommon to find gold plated contacts with nothing left but a thin
sheet of gold. All the copper was corroded away leaving nothing but the
gold. Corrosion like this is common on the HP calculators and it's what
happens when you plate gold directly over copper. The proper way to do it
is to plate nickel or other non-porous material over the copper and then
plate gold over that. The nickel will prevent the acids and oxygen from
penetrating the surface and corroding the copper. FWIW on OLD cars they
used to plate steel with copper, then nickel and then chrome plate over
that. Plating like that will easily last 40 years (speaking from experience).
Joe
or an amalgam of
>copper and gold ( and possibly other metals) Have you tried a dremel tool
>with a dry polishing wheel - no solvent or compound? Use it lightly. This
>has worked wonders for me though it does take patience.
>
On Oct 3 2005, 13:28, Mark Tapley wrote:
> Broken component is the hard drive from a La Cie Tsunami
> external enclosure. Drive is a Quantum Prodrive LPS, 240 MB capacity,
> 1) Is the HA13476 expected to be pretty warm in use?
>
> 2) What is an HA13476? Is it unobtanium
Don't know...
> 3) Anyone have a matching drive that I could get at reasonably low
> cost to try exchanging controller boards?
...and too far away...
> 4) Any suggestions for further trouble-shooting and/or repairing?
...but I can offer some possible comfort, in that I have swapped boards
between Quantum Prodrive LPSs of that sort of size successfully, even
when the drives participating in the swap have not been the same size
as each other. Might need to swap the ROM as well, but the ones I've
seen are all socketed.
--
Pete Peter Turnbull
Network Manager
University of York
I intend to return the 5028 to working condition. If, even in its
terrible cosmetic condition, the 5028 is needed as part of somebody's IBM
collection, I will trade it for a regular ASR33. But shipping from NYC
would be expensive and quite possibly destructive. -kurt
I have no idea exactly what model (could LCII screens be used with
anything other than an LCII?), but we have more Apple hardware than we
need right now - if anyone wants to chase this one up, then contact
Mavis Beard direct on mavis.beard at btinternet.com
Seems like a good way of getting a stock Apple machine in nice condition
at the very least.
<<<
I wonder whether you can help please - I wish to find a home for the
following computer which I now no longer need and I have been advised to
contact yourselves:
Apple Mac Computer with Claris Works
Mackintosh LCII Monitor
Mouse
Keyboard
Modem
Printer Stylewriter II
This is in very good condition, in fact hardly used so hope you can
take it on board.
>>>
