Any parts of a LASERJET 5Si that can be salvaged?

[Tom MacIntyre]

On Sat, 25 Jun 2005 20:25:25 GMT, "Angrie.Woman"
<Angrie.Woman@ggmail.com> wrote:

BrotherBart wrote:
I have a question. If I put a cellphone in a microwave oven, close the
door, call the number....should it ring?


A


Why is it that I feel the need to ask "Did it?"?



Yes...the last "real" job I had was for a telecommunications services
provider. They installed and maintained towers, as well as the cellular,
and microwave equipment, associated with all of it.

The guys used to do that to prove that the ovens weren't really all that
well insulated, but I always wondered if there was another reason that
might happen.
A

They are probably well-insulated for their own particular frequency.

Tom

 

[Tom MacIntyre]

On Sun, 26 Jun 2005 10:25:57 -0400, Joseph Gwinn
<JoeGwinn@comcast.net> wrote:

In article <pBlve.5142$dY1.3431@trnddc06>,
"James Sweet" <jamessweet@hotmail.com> wrote:

One time we were sending a bunch of CRT's back to the manufacturer for
proof-of- replacement one time, and my wife was labelling them. She
was wearing a knitted sweater, and the sleeve brushed against the 2nd
anode. She wasn't pleased with the result. The CRT had been sitting
for weeks to months...

Tom

A CRT that's not connected to the HV lead won't have any path to ground to
bleed the charge off, it'll pick up static from the air over time.

The issue with CRTs is that the glass dielectric, having been kept at
many tens of kilovolts for years, will store charge deep in the glass,
and this charge cannot be eliminated quickly. The phenomena is called
"dielectric adsorption" or "soakage". One can short such a CRT for a
week, remove the short, and see the voltage magically spring back. So
leave it shorted.

Dielectric absorption is one of the factors that the Sencore LC line
of capacitor/inductor testers measures. Thanks.

Tom

Big capacitors can do this as well, especially the big oil-paper
capacitors used in HV power supplies. These can store a lethal jolt.

This same phenomena is used in Electret microphones, where a thin layer
of teflon stores the HV charge needed to make the microphone work.

Joe Gwinn

 

[lionslair at consolidated]

Angrie.Woman wrote:

Koz wrote:




I know that old printers/copiers are cheap as dirt (free often) and
can be used the same way, although they don't have quite as many parts
as those old calculators. I've had my daughter take apart a couple of
similar things as a learning experience (help dad by salvaging parts).
Any other ideas on cheap mechanical junk that is readily available and
may be a great learning experience for the mechanical kid to monkey
around with?

Koz



Anything. My #1 son is a "take apart junkie." he takes his wagon out
bright and early every monday morning to find stuff to bring home and
dismantle. We've done toasters, VCR's, tape recorders, toys - all kinds
of stuff. Last week we did an aqua-pic and a hose sprayer that had an
adjustable flow thingy. A 35mm camera was cool - about a gazillion parts
crammed into a 3 x 5" box. Amazing to me, who can't seem to even fit all
our clothes into the closet.

If you've got no pride, just pick up anything but a TV (unless you know
how to discharge the cap) from the garbage and give it a go.



A
TV discharge is easy. A stick with a nail in the end, that has a wire

attached that is 'clipped' to the metal chassis. The nail is (when holding the
wood stick - and insulated nicely (broom stick...) is slid under the HV plug.
The arc will be under the plug cap and should be heard. e.g. if not - try again
and wiggle around. Once done, or decided not needed - then the nail on stick
is used (still attached - just in case) - and is hammered - slightly - through
the metal seal that serves as the high voltage connector. Air flow will follow.
Allow a slow flow. Breaking rapidly might implode the 'tube' end through the screen.
So that is the reason to punch it with a nail. (or punch...)

Naturally, it is a hasmat item - lead in the glass, phosphor in the screen, metals in
the metals... Best to be left alone.

Martin

--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

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[jakdedert]

NSM wrote:

"Christopher Tidy" <cdt22NOSPAM@cantabgold.net> wrote in message
news:42BDFFE7.6020909@cantabgold.net...

I suspected so. I imagine that if you peed from a height of more
than a few feet, the stream of urine would break up into droplets
and would not form the necessary conductive path. Still, I wouldn't
want to try it with 25 kV.

In New Zealand they have interisland undersea lines which run at 500
KV DC IIRC and they wash the salt off the insulators with a 'chopped'
spray jet of water. Scary job IMO.

N

I remember getting 'bitten' by an electric fence on which I played a stream
of water from a garden hose, as a kid. The charger was the 'pulsed' type
which used a 6v battery, inductor and 'balance beam' switcher for power.
The hose had no nozzle on it, so I was using my finger to direct the spray.
The distance was only a few feet, and the jolt was roughly comparable to
touching the fence directly--it was never too effective even with direct
contact...

jak

 

Ignoramus26555 wrote:

At my work, they are throwing away a HP LaserJet 5SI printer. I am
thinking that perhaps there is something valuable here, like stepper
motors or whatever that I can salvage for my "projects". Any
suggestions?

i

Given what they get for refurb and pulled parts for these printers, a
computer parts recycler would probably pay a not inconsiderable amount
for the carcase, even if it seemed totally dead. Some places, tossing
computer parts in the trash will get you in legal trouble. I've never
actually tossed an HP laser printer, they've always been revivable with
a little effort. The paper trays alone are worth a bunch.

For parts of interest, you've got a laser in there, some kind of
scanning mirror and motor, rudimentary optics, gears and bearings, a
power supply with semi-HV output. The sum of the individual parts and
assemblies is far more than the whole works costs.

Stan

 

[Ron Bean]

Ignoramus26555 <ignoramus26555@NOSPAM.26555.invalid> writes:

At my work, they are throwing away a HP LaserJet 5SI printer. I am
thinking that perhaps there is something valuable here, like stepper
motors or whatever that I can salvage for my "projects". Any
suggestions?

Why are they throwing it away? If it's repairable, it's probably
worth more as a printer than as anything else.

If it's a paper jam problem, see this link:
http://www.fixyourownprinter.com/kits/hp/12

 

[Too_Many_Tools]

Good article...thanks for posting it.

A related question for the group...what kinds of electronic "trash" IS
worth disassembling and keeping?

TMT

 

[Too_Many_Tools]

Your son is a very lucky kid to have a parent that allows and
encourages self discovery.

My parents had to hide the screwdrivers from me...nothing was safe from
my curious mind.

I predict that your son has a great future and an interesting life
ahead of him.

If I were his parent, I would be very proud of him.

Good luck with the great adventure of parenting.

TMT