>> The only things I don't like are it doesn't last very long. So I find I
>> have to refill more often than I would like. Part of the rapid loss of
>> air is because one of my connections isn't air tight, so if I leave the
>> tank turned on, it slowly bleeds itself (it will go empty over night),
>
>Is it a screw fitting? Take it apart and wind 4"-6" of PTFE tape round it
>the male fitting. You can get the tape from any place that sells air
>accessories or vacuum pumps, or most plumbers suppliers.
I believe the leak is in one of the screw fittings. They didn't provide
tape with the tank when I bought it, instead they provided a small tube
of sealant, and the tube was WAY to small to do the job (barely enough to
properly seal one fitting, much less the other 4 needed to complete the
setup!).
So I am sure the leak is just one of the fittings that I did with no tape
or sealant. I've just never gotten around to buying the tape and taking
it all back apart (about 2 or so years now that I have had the tank).
Each time I think that I should run to the store and get a roll of
tape... I figure I might as well just get a whole new compressor/tank
combo so that I have a larger tank, and one that I can leave one and not
worry about it blowing the tank... and then I think, I'll do just that,
but I'll wait for a sale... then a sale comes, and I decide I don't want
to spend the money... then I go to use my existing tank, forget to turn
it off when done, and it leaks itself empty... and I think I should go to
the store and get a roll of tape... and the cycle continues.
-chris
<http://www.mythtech.net>
On Jan 21, 5:27, Jeffrey Sharp wrote:
> The goal: extremely localized, high-velocity stream of air. I want to
remove
> dust and crud from those impossible nooks and crannies of classiccmps.
>
> Current solution: canned air - expensive, doesn't work well after one or
two
> minutes of spraying, not really high enough velocity. Bad.
Those cans get flipping cold, don't they?
> Other options:
> - Shop-Vac in reverse operation, fitted with custom cable?
Beware static. And you may find the pressure isn't as high as you'd like.
> - Better, cheaper canned air (does it exist)?
Scuba gear.
> - Dust-removing nano-bots? (jk)
If you find any, let me know :-) Maybe we can retrain/reprogram them to
repair stuff too.
> - Compressor? (I don't know much about these).
I've taken this out of order, because it's what I now use. I bought a
small electric compressor and some air tools (used for other things than
classic computers) for under UKP100 (about US$140). Things to watch out
for:
Compressors are fairly noisy animals. Mine is quiet as such things go, but
still louder than the high-power vacuum cleaner I have.
The vacuum is better than a blower to remove dust (think about where that
dust will go). OTOH, a blower is much better for drying things off, or
getting into things the vacuum+paintbrush can't. The vacuum, however, is
better for spiders.
Any fast-moving air stream can generate static. You can alleviate/prevent
that by using a grounded metal nozzle.
Even a small compressor will deliver pressures well in excess of 100 psi,
and that's way too high for use on electronics. You can rip components off
boards, never mind rip disk heads off. 20-40psi is perfectly adequate, and
it will deliver higher velocity than most aerosol cans give you.
One of the air tools I have is a small pistol-grip-style trigger-operated
blow gun. You can buy them separately for about UKP3, or say $5. For
example, see http://www.series4.co.uk/s4shop/en-gb/dept_123.html, or
http://www.sip-group.com/PAGES/800x600%20PAGES/Air%20Tools.html (the one I
use looks like 02130, under "Dustres" on that page). These are much easier
than turning the Shop-Vac on and off.
Many compressors include a small amount of oil in the airstream to
lubricate air tools, deliberately added either by an oiler, or as a
byproduct of the oil system used by the piston. However, you can get
oil-less compressors perfectly easily, and oil any tools that need it by
adding a drop in the inlet periodically, or fitting an oiler, or
filter/water-collector/oiler combo, in the airline. They're not expensive.
You can get cheap compressors without a receiver (air tank). Don't bother.
You can also save a few $$$ (not many!) by buying one with a "regulator"
which is really an adjustable blow-off valve to vent the excess air, rather
than a proper pressure-reducing regulator. Given the choice, take the
proper regulator; the compressor will usually also have a cut-off for the
pump to stop it when it gets up to full pressure in the receiver. You
*need* a *good* regulator to run an airbrush properly.
If you want a compressor for other tools besides a blower, remember that
the piston displacement, measured in cu.ft/min, is typically only about 2/3
the available air delivery you'll actually get, and a lot of
hobbyist/low-usage compressor pumps are only rated for a 50% duty cycle (10
minutes on, 10 off, commonly). The pump gets HOT. If you ever plan on
using something like a die grinder, you want a compressor rated for about
three times (or more) the listed air consumption of the tool.
If you buy quick-release couplings, be aware there are at least three
standards, and they're not interchangeable.
I'd recommend buying a small compressor. Mine is great, though I sometimes
wish I'd bought a slightly bigger one. Whether you buy a scuba tank or a
compressor, just think of the cost and inconvenience of ten cans of
high-pressure air duster.
--
Pete Peter Turnbull
Network Manager
University of York
>From: "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com>
>
>On Tue, 21 Jan 2003, Ron Hudson wrote:
>> > Other options:
>> > - Shop-Vac in reverse operation, fitted with custom cable?
>> Beware static!!!
>
>LOW pressure, high volume
>
>> > - Compressor? (I don't know much about these).
>> Compressors can add very small ammounts of oil to the air, thus SCUBA
>> divers fill don't
>> fill their tanks at the local gas station but instead us special
>> compressors.
>
>gas stations also don't have >1000 PSI.
>
---snip---
Today, they have those little coin operated compressors.
When they used to have the large tanks, they would often
have them set to 200 PSI. My brother made the mistake once
while filling a bicycle tire that you don't just hold
the button for several seconds before checking. He'd
gotten used to filling car tires. It when errrRRRAck-BANG!
He really blew the tire. I had to ride home and get
his car to pick him up. It even bent the rim.
Dwight
Hi Bill
Jameco still list both 8212's and 8216's.
Dwight
>From: "Bill Sudbrink" <wh.sudbrink(a)verizon.net>
>
>I've just finished building and checking out a minimal
>Intel MCS-85 SDK. Was fun to build and runs like a champ.
>Not bad for sitting in storage since 1979. The only
>annoyance was that the black anti-static foam had turned
>to crud and tarnished all of the IC pins.
>
>Anyway, now I would like to expand it a bit. The board
>and schematics call for 2 8212 address drivers (24 pin dip)
>and 5 8216 buss buffers (16 pin dip) to drive the interface
>to the breadboarding area. All of the other chips on the
>board have 1977 or 1978 date codes so, if possible, it
>would be fun to get matching chips. If these things are
>"hen's teeth", then I'll take whatever I can get.
>
>Thanks,
>Bill
>
>
Hi
One should at a long bristle brush. Even with air,
one still gets more effect from moving it around a little.
I usually use a 1 inch wide paint brush.
Dwight
>From: "Jarkko Teppo" <jarkko.teppo(a)er-grp.com>
>
>
>Jeffrey Sharp said:
>> - Compressor? (I don't know much about these).
>
>Compressor. Works wonders for dust and good for removing those extra
>TTL-chips from circuit boards.
>
>Canned air is (unless you're "in the field") useless. Couple of shots
>and that's it.
>
>--
>jht
Careful !
Compressed air is dry and in a dry environment the blowing action quickly
generates a static charge.
Most CC equipment is particularly sensitive to static damage.
I prefer warm water and a brush -- sometimes with mild dishwashing soap.
-Rob
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]On
Behalf Of Jochen Kunz
Sent: Tuesday, January 21, 2003 6:47 AM
To: cctalk(a)classiccmp.org
Subject: Re: What's better than canned air?
On Tue, Jan 21, 2003 at 05:27:49AM -0600, Jeffrey Sharp wrote:
> Discuss, please. What do *you* use instead of consumer canned air?
- Brush and vacuum cleaner.
- Compressor. Use one that runs without oil. Some compressors need oil
to run and are "contaminating" the air with it. Somtimes there are litle
extra devices on the compressor to put a bit of oil into the air. Air
driven machines need it. But it is not good for electronics.
- Sometimes warm water and a brush to "simulate" a dishwasher. See the
endless dishwasher discussion. Soak PCBs after washing in Isoprop and
let it dry for some days.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
I've just finished building and checking out a minimal
Intel MCS-85 SDK. Was fun to build and runs like a champ.
Not bad for sitting in storage since 1979. The only
annoyance was that the black anti-static foam had turned
to crud and tarnished all of the IC pins.
Anyway, now I would like to expand it a bit. The board
and schematics call for 2 8212 address drivers (24 pin dip)
and 5 8216 buss buffers (16 pin dip) to drive the interface
to the breadboarding area. All of the other chips on the
board have 1977 or 1978 date codes so, if possible, it
would be fun to get matching chips. If these things are
"hen's teeth", then I'll take whatever I can get.
Thanks,
Bill
Should anybody be interested..
www.meco.org has a SGI Crimson in WA state.
REF NUM: [crimson]
ITEM NAME: Crimson VGXT CPU
PRICE [345.02]
Description: With 1.2G disk, 256M Ram, VGXT Graphics, DAT, and CDROM.
Shipping on the bloomin' thing put it out of my price range. (And made
it cost more than its worth.)
David
AFAIK, the H7xx power bricks of the 11/34 (among others)
work without any load. At least that is the way I repaired
2 of those up till now.
When the voltage output is present (again), adjust it to
the nominal value (without load).
Expect a small adjustment of the output voltage when the
brick is installed and connected in the PDP-11.
Hint: make a note near the opening from where you adjust
the potentiometer. It saves some sweat on your forehead
when you think "which direction and how much do I turn
the screwdriver?".
success,
- Henk.
> -----Original Message-----
> From: Jeffrey Sharp [mailto:jss@subatomix.com]
> Sent: dinsdag 21 januari 2003 12:18
> To: cctalk(a)classiccmp.org
> Subject: 11/34 PSU (Was: RK07 repairable?)
>
>
> On Friday, January 17, 2003, Tony Duell wrote:
> > One tip. If you have the 'bricks', make up an extension
> cable -- 8 pin
> > mate-n-lock plug to socket, all pins wired. You can run the 'bricks'
> > outside the box then, for short periods with low load
>
> How low of a load can I go with the 11/34 bricks?
>
> (I want to start working on my 11/34 soon! It sounds like I
> can still do
> this with my very limited electronics knowledge.)
>
> --
> Jeffrey Sharp
>
>
