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Guest

Speaking of radio controlled toy cars.I would like to find a hollow
rigid plastic ball that is easy enough to take apart in two pieces.I
want to put a small radio controlled toy car inside of the hollow
plastic ball and try it out.
cuhulin

William Sommerwerck · Guest

There used to be a radio-controlled toy called a Motoball. I can>t find any
on eBay, and any Google references have been swamped by the sport of the
same name.

Guest · Posted: Sat Oct 04, 2008 9:20 pm Post subject: Re: 9 mV noise on AC voltmeter

I have three Fluke meters, bought them at pawn shops years ago.One of
them has a plug in thermister wire.They all need new batteries.I use Ray
O Vac alkaline batteries.I don>t like keeping up with recharging
rechargable batteries.I al Lazy.
cuhulin

Guest

I have a little battery powered toy ball that sort of looks like a
squirrel hanging onto the ball by a string.I bought it at a Goodwill
store.Little doggy, she isn>t interested in the toy.
cuhulin

Bryce · Guest

cuhulin@webtv.net wrote:

[quote]On the web, Oudin Devices

I looked and I saw, www.museumofquackery.com/devices/uv.htm

Third picture down, that large pencil/crayon looking thingy looks just
like the device I have.
cuhulin, the quack
[/quote]
I remember the same one. We had the whole collection of tubes and
snazzy case. In addition to the discharge tubes, there was a tubular
metal wand that could be plugged into the spark coil. Produced
quite a jolt.

I suppose it>s too late to join in the class action suit.

Andre Majorel · Guest

On 2008-10-04, William Sommerwerck <grizzledgeezer@comcast.net> wrote:
[quote]It is normal that on the very low voltage AC scale and the leads
are terminated, the meter will read something. The reading may
be in the area of a small number of millivolts.

True, but the OP stated that the reading was the same whether
or not the leads were shorted.
[/quote]
I didn>t make myself clear. With the leads open, you get on the
order of 1 V, which doesn>t surprise me considering the 10 M
input impedance of the meter.

What I don>t get is how, after shorting the plugs with a 2-cm
long piece of wire, switching to "Velec" mode (270 k input
impedance), switching off all monitors and fluorescent lamps in
the vicinity and going outside, you *still* get 9 mV.

Still no service manual forthcoming from Chauvin-Arnoux. What.
A. Surprise.

[quote]I checked my Fluke 87 set to 4.5 digits. With the leads open,
I get a residual of about 3mV (though this varies with the
lead position and separation, of course). When the test leads
are shorted, the reading drops to less than 2mV and stays
there.

I>d say there>s definitely something wrong with the OP>s
meter. Whether it>s significant is another matter.
[/quote]
--
André Majorel <URL:http://www.teaser.fr/~amajorel/>
You measure democracy by the freedom it gives its dissidents, not
the freedom it gives its assimilated conformists -- Abbie Hoffman.

Guest

In rec.antiques.radio+phono N_Cook <diverse@tcp.co.uk> wrote:
[quote]As far as heaters are concerned. I went to a lecture by Tony Sale of
Colossus rebuild fame
http://www.codesandciphers.org.uk/lorenz/mk2.htm
About 2,500 valves in this computer.
They power up Colossus each day via a motorised variac.
How many valve failures a year, due to failed heaters in those 2,500, would
you expect ?
Please reply here
[/quote]
Say, it runs 8 hours a day, every day... That is 2922 hours of operation a
year. By rough estimate, every 5 years the complete valve supplement will
be renewed. That is 500 valves a year. When it runs only 4 hours a day, it
will be half this number, etc.

--
Met vriendelijke groet,

Maarten Bakker.

Guest

In rec.antiques.radio+phono N_Cook <diverse@tcp.co.uk> wrote:
[quote]About 5 valves a year need replacing.
IIRC about 1,000 of them are thyratrons, 2 are needed for each single bit of
memory storage. The mark 1 did not have them and required running 2 loops of
paper tape , the mark 2 required only 1 paper tape loop
[/quote]
I should have consulted both the life expectany figures of the tubes, and
the rest of the thread before answering too late. Is 5 valves a year a
long term average?

--
Met vriendelijke groet,

Maarten Bakker.

b · Guest

On 3 oct, 10:13, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
[quote]page.

It>s a very common problem on Philips PSU>s. Replacement type is not
critical. Just about anything of similar rating, intended as a smps
secondary reccy, will work perfectly well in my experience.

Arfa

just tried a BY255, but got erratic operation and overheating -
probably couldn>t handle the frequencies of the SMPS..... today I
bought an exact replacement schottky so will post back when
installed. Ben

???????????????
I guess I wasn>t clear enough when I said

"intended as a smps secondary reccy".

The *exact* type is, as I said, not critical. The *generic* type of course
*is*. A secondary-side reccy in a smps *must* be a high speed job, typically
a Schottky type, as you were originally asking about. Sorry if I implied
otherwise ... :-)

Arfa
[/quote]
no worries Arfa, my misunderstanding. Anyway I fitted an SB 560 and
all seems well. thanks for all the responses!
B.

Too_Many_Tools · Guest

On Sep 25, 6:43 am, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:
[quote]Start by checking Thomas Distributing.

By the way, 400mAh (not 400mA) is a low capacity for a modern nicad.
[/quote]
You are correct...thanks for the correction.

TMT

Samuel M. Goldwasser · Guest

cuhulin@webtv.net writes:

[quote]On the web, Oudin Devices

I looked and I saw, www.museumofquackery.com/devices/uv.htm

Third picture down, that large pencil/crayon looking thingy looks just
like the device I have.
cuhulin, the quack
[/quote]
Yep, they show up on eBay from time=to-time, complete with the
gas tubes.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam>s Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Jeff Liebermann · Guest

On Thu, 2 Oct 2008 12:32:41 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:

[quote]About 5 valves a year need replacing.
[/quote]
Very impressive. I thought it would be much worse.

[quote]IIRC about 1,000 of them are thyratrons, 2 are needed for each single bit of
memory storage. The mark 1 did not have them and required running 2 loops of
paper tape , the mark 2 required only 1 paper tape loop
[/quote]
That>s cheating. Thyratrons are gas filled (usually hydrogen) low
pressure devices. They>re also sometimes run with a relatively cold
cathode. The traditional failure mode is silicon and other impurities
in the filament slowly coating the cathode and ruining its ability to
emit electrons, is less of a problem with gas filled tubes such as
thyratrons. Thyratrons were probably chosen over the faster vacuum
tubes for that reason.

<http://www.tnmoc.org/ColRbd.htm>
"Mainly Mullard EF36 pentodes but also 6J5 triodes, 6V6
and 807 tetrodes and the GT1C thyratrons"

GT1C thyratron:
<http://www.tubecollector.org/gt1c.htm>
4V at 1.4A for the filament. So much for the cold cathode theory. I
guess that came later.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Arfa Daily · Guest

"Jeroni Paul" <JERONI.PAUL@terra.es> wrote in message
news:5e65f477-e8f6-42dd-9b96-ef2beee1e956@26g2000hsk.googlegroups.com...
On 30 Set, 10:02, IanM <Inva...@totally.invalid> wrote:
[quote]A CLV drive will need a significantly better motor and some care in the
mechanical design to prevent resonances. A CAV drive can have much
cheaper mechanicals and can handle random access. (A CLV drive has to
diddle the motor speed on every seek till the tracking servo locks again
- slow and clunky.)

Add in marketing factors like selling on buffer size and that a CAV
drive claiming a particular access speed may only run that fast on
AVERAGE across a maximum length disk, and I>d be surprised to find any
new ROM drives that still do CLV. Recorders are a different matter, Its
gotta be easyier to get a consistant result at CLV and I wouldn>t be
surprised to see both strategies in the same high end drive depending on
recording speed selected and type of disk.- Amaga el text entre cometes -
[/quote]
Well, CD-ROMs for PCs appear to use CAV since the disk always rotates
at the same speed, except when it is having difficulties to read.
But some cheap set-top DVD players use CLV. In one I repaired the
motor was a standard DC brush motor and a double power op-amp driver
chip. The controller set the speed by adjusting a voltage, and it
could not only accelerate but also brake by taking away power
generated in the motor. Without the braking it did play but would
stall at the first seek to the end of the disk.

I think you>ll find that pretty much all domestic entertainment DVD players
/ home cinema units, irrespective of their cost or pedigree use CLV servos.

Arfa

William Sommerwerck · Guest

If digital disk players -- for whatever format -- were CAV, they>d have
roughly only half the recording time they do. They don>t need CAV, as the
constant clock rate allows timing variations to be corrected.

Geoffrey S. Mendelson · Guest

Arfa Daily wrote:
[quote]Presumably, on drives which used CAV servos, the reverse principle is used
for playing back ? If so, it must all work out the same, otherwise, a
commercial disk would not play in both your CAV computer drive, and the CLV
drive in your home cinema unit.
[/quote]
It could just be that the microprocessor in the drive detects the current
bit rate and reads it accordingly. That way a disk can be written in
in almost any method at almost any speed and still be read.

This compensates for buggy writers, component aging, etc.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com N3OWJ/4X1GM


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