Toshiba TV29C90 problem; Image fades to black...

[Charles]

"Blattus Slafaly" <boobooililililil@roadrunner.com> wrote in message
newsuidncUsk40swkDVnZ2dnUVZ_rrinZ2d@giganews.com...

I'd like to modify a remote TV control. Put a small microphone on it
with a volume control and an LED indicator plus a small timing circuit.
You would use the volume control to set the current speaker level with
the LED indicator and just back it off a touch. When the loud commercial
comes on the LED blinks, auto mutes the TV with the mute button and
starts the timer for 60 seconds. After 60 seconds the mute button is hit
again and sound comes back on. If the sound is still above set level it
mutes another 30 seconds and continues this until the sound returns to
normal levels.

There must be enough off-the-shelf stuff to do this with and have it fit
inside the remote. You think?

The "mute" button works well here.

 

[Arfa Daily]

"Jerry" <jerry_maple@hotmail.com> wrote in message
news:d4be2671-9cd9-4b69-b31b-a986f6d680d2@m3g2000hsc.googlegroups.com...
On Sep 26, 9:31 am, JR North <junkjasonrno...@bigfoot.com> wrote:

Are there variables like disc brand, Xspeed rating, recorder
settings(SP/LP, etc),that have been known to influence this fault in a
positive direction? I don't really want to embark on a lengthy
experiment by buying all the different disc choices and testing, only to
come up unsuccessful.

Disc brand is a definite variable. When I first started recording
DVDs, I bought a big spindle of GQ (Great Quality - HAH!) blanks from
Frys Electronics. Things that I recorded on them would be OK at the
start, then start breaking up at the end. DVDs record from the inside
to the outside, so the linear speed past the laser is faster at the
end, thus more difficult to write and read reliably.
<snip>

That isn't true, I think. CD and DVD use constant linear velocity (CLV)
servos, rather than constant angular velocity (CAV). This means that as the
laser tracks from the centre to the outside of the disc, the rotational
speed of the disc is slowed, to maintain a constant writing or reading speed
of the track, past the optical block.

Arfa

 

[Curtis Brown]

"JR North" <junkjasonrnorth@bigfoot.com> wrote in message
news:Ct2dnYJblaIYk0DVnZ2dnUVZ_qadnZ2d@seanet.com...

\rant
OK, I haven't thought this through completely before posting, but...
I have 2 DVD recorders, one Toshiba DVD-R, one Sanyo DVD+R/DVD+RW. Both
work well.
Movies recorded on either won't play properly on DVD 'players' like my
Toshiba 9"TV/DVD or my new Audiovox 15" LCD TV/DVD. Recorded Discs from
both recorders will start OK, but 5-15 minutes into the first title, start
displaying digital artifacts, then eventually stall. Neither will play a
second title.
I know various manufacturers state that their units may not play discs
recorded on other units. What's up with that? Just what is 'Versatile'
about DVD that makes it so un-versitile?
Before I start really raving on the absurdity of this bullshit, and just
exactly what's wrong with the consuming public that this is tolerated, let
me digress.
/rant
Are there variables like disc brand, Xspeed rating, recorder
settings(SP/LP, etc),that have been known to influence this fault in a
positive direction? I don't really want to embark on a lengthy experiment
by buying all the different disc choices and testing, only to come up
unsuccessful.
I bought both DVD players to play my recorded DVDs on my boat. As of now,
this plan is defunct.
More information later...
Any input?
JR



--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth

That's what you get for infringing on other people's copyrights.

 

[William Sommerwerck]

This is an interesting group
I just had an impedance issue i got help with on a project that I am
working on, in summary
I used CO sensors in a parking garage the rating on the comunication
bus is 2000ft, When I designed the project during estimation I took a
risk to strech to 3000 based on the probability that the voltage drop
would not migatate me. Anyhow to make a very long story short, it
turned out between my low volatge sub and my inherient nature for
taking small calculated risks, the com was 3500 ft, I tried to figure
out the best end of the line terminator , going back to the impedance
matching topic that sparked my interest, after calling some experts, I
got the matched impedance, but still need to and another 50VA
transformer.... lesson learned on my part

Thanks for sharing
Allan J Federman
allanfederman@gmail.com

Mr. Federman, your writing verges on the incomprehensible. I have little
idea what you're talking about or trying to say.

I hope communications with your customers aren't so opaque.

 

[Mark D. Zacharias]

"Steve" <s@s.c> wrote in message
news:ur80e45goud4jrv8g11ihgr9je2ge9md4c@4ax.com...

On Mon, 29 Sep 2008 08:02:01 +1000, Franc Zabkar
fzabkar@iinternode.on.net> wrote:

On Sun, 28 Sep 2008 16:27:43 -0500, Steve <s@s.c> put finger to
keyboard and composed:

On Mon, 29 Sep 2008 06:51:58 +1000, Franc Zabkar
fzabkar@iinternode.on.net> wrote:

On Sun, 28 Sep 2008 15:11:30 -0500, Steve <s@s.c> put finger to
keyboard and composed:

I have a Kenwood VR-407 which keeps going into protection. The ą12VDC
supplies are unbalanced. The schematic for the circuit is posted in
a.b.s. It's just a basic circuit, it uses a center tapped transformer
feeding into a full-wave bridge, with the center tap grounded, with a
positive and negative three terminal 12 volt regulator. No rocket
science here. However, the supplies are unbalanced, pretty severely.
The input to the bridge is 14.24 & 14.15 VAC. The output of the
bridge is -25.28 & 10.23VDC with .685 & .240VAC ripple, respectively.
I pulled the board from the unit and powered up each regulator
individually . With -18VDC in across the negative, there was .1A draw
& -11.90VDC out. With +18V in across the positive regulator, there
was .1A draw & 11.83VDC out, so the reguators are fine and neither has
excessive current draw down the line. When I put an external supply
across both bridge capacitors I saw the same unbalance. With 35VDC
across the caps, there was 25.94 across the negative cap and 8.99V
across the postitive cap. I connected a capacitor in parallel across
both caps individually, but it didn't create any significant change.
Is it probable that one of the caps is bad causing the unbalance?

Thanks, and I'll provide any more information if necessary.

You can interchange the capacitors to see if the unbalance goes with
the cap. However, it looks to me like you may have an open centre tap,
or the trace between the centre tap and the junction of the caps may
be open.

- Franc Zabkar

The center tap checks good, as well as the trace between center tap to
the capacitor center point. Also, the bridge checks out ok. I guess
I need to pull the regs & put voltage across the caps & see if I have
unbalance then. Also, the caps are different sizes, it looks like
they may have designed the circuit to have higher current out of the
12v reg, which makes perfect sense, I guess the caps could have aged
at different rates then being dramatically different sizes. I'll do
some more testing, thanks for the replies.
Steve

How can you get 25VDC across a cap when the AC supply is only 14Vrms?
The maximum voltage should be only ...

14 x 1.414 = 19.8 - Vf(diode) = 19V

Try desoldering each bridge diode one at a time. That way you'll be
able to test each half of the bridge on its own.

- Franc Zabkar

I'll have to remove the bridge as a whole, it's a four terminal
package. I was using a Fluke 87 III for the measurements. What you
said about the center tap makes sense, that would explain everything,
but it measures fine, .9 ohms between either winding & center, 1.8
total. I'll yank the bridge & caps tomorrow, it can't be too hard to
find, this is a simple circuit for heaven's sake.

Thanks for the posts,
Steve

Definitely a loss of ground reference. I've run into this several times
lately.


Mark Z.

 

[Mark D. Zacharias]

<daniellarsennz@gmail.com> wrote in message
news:810f2921-4b83-4880-900a-3ad567cc7649@b1g2000hsg.googlegroups.com...

Hi,

Does anyone know how to reset a Sherwood RD 6118R AV Receiver?
Recently the surround channels have gone to 100% volume at all times
(except when muted), regardless of what the master volume is. Front
and centre are OK. Same behaviour in Dolby Digital and Pro Logic
modes.

Any help appreciated.
- Daniel

Only worked on one later model Sherwood, but it was a Denon built one, and
reset issues are quite common on those.

No reset procedure was given, but I was able to bleed off the backup cap and
it fixed the problem in my case.


Mark Z.

 

[Arfa Daily]

"Jerry" <jerry_maple@hotmail.com> wrote in message
news:24a7ffbc-569b-45fa-9030-a656f406d641@q9g2000hsb.googlegroups.com...
On Sep 26, 5:36 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

That isn't true, I think. CD and DVD use constant linear velocity (CLV)
servos, rather than constant angular velocity (CAV). This means that as
the
laser tracks from the centre to the outside of the disc, the rotational
speed of the disc is slowed, to maintain a constant writing or reading
speed
of the track, past the optical block.

If you can believe everything you read on the internet, I saw the
following on the DVD Demystified website :
http://www.dvddemystified.com/dvdfaq.html#1.1.
Leads me to believe that there are both CLV and CAV drives out there.

--

In order to maintain constant linear density, typical CD-ROM and DVD-
ROM drives spin the disc more slowly when reading or writing near the
outside where there is more physical surface in each track. (This is
called CLV, constant linear velocity.) Some faster drives keep the
rotational speed constant and use a buffer to deal with the
differences in data readout or writeout speed. (This is called CAV,
constant angular velocity.) In CAV drives, the data is read or written
fastest at the outside of the disc, which is why specifications often
list "max speed."

Jerry

That's interesting Jerry. I've never before seen any writeups on CD/DVD
rotation control systems, which suggest that anything other than CLV servos
are used. I suppose that if you keep the angular velocity the same, and vary
the data transfer rate, then in terms of what's actually recorded, that
amounts to the same thing, achieved by an alternate method. That being the
case, then your original point about the writing speed at various places on
the disc makes a lot more sense. Thanks for the info. I wonder what exactly
is the thinking behind doing it in what seems to be a more complex way that
requires a chunk of buffer memory, and why this should be (apparently)
associated particularly with 'high speed' writers ? Time for some more
research, I think !

Arfa

 

[Arfa Daily]

<snip>

That's interesting Jerry. I've never before seen any writeups on CD/DVD
rotation control systems, which suggest that anything other than CLV
servos are used. I suppose that if you keep the angular velocity the
same, and vary the data transfer rate, then in terms of what's actually
recorded, that amounts to the same thing, achieved by an alternate
method. That being the case, then your original point about the writing
speed at various places on the disc makes a lot more sense. Thanks for
the info. I wonder what exactly is the thinking behind doing it in what
seems to be a more complex way that requires a chunk of buffer memory,
and why this should be (apparently) associated particularly with 'high
speed' writers ? Time for some more research, I think !

Arfa
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.

Yes, that seems to make a lot of sense. Maybe the reason that I have not
come across this, is that most of my day to day experience with CD / DVD
drives, is on 'entertainment' equipment, rather than computer based drives.
Good to discover something new. I guess it's true that you never stop
learning 'til the day you die. d;~}

Arfa

 

[Mark D. Zacharias]

"Steve" <s@s.c> wrote in message
news303e4dkuut21k5t388tglmmplj8pclhfe@4ax.com...

On Mon, 29 Sep 2008 05:37:36 -0500, "Mark D. Zacharias"
nonsense@nonsense.net> wrote:


"Steve" <s@s.c> wrote in message
news:ur80e45goud4jrv8g11ihgr9je2ge9md4c@4ax.com...
On Mon, 29 Sep 2008 08:02:01 +1000, Franc Zabkar
fzabkar@iinternode.on.net> wrote:

On Sun, 28 Sep 2008 16:27:43 -0500, Steve <s@s.c> put finger to
keyboard and composed:

On Mon, 29 Sep 2008 06:51:58 +1000, Franc Zabkar
fzabkar@iinternode.on.net> wrote:

On Sun, 28 Sep 2008 15:11:30 -0500, Steve <s@s.c> put finger to
keyboard and composed:

I have a Kenwood VR-407 which keeps going into protection. The
ą12VDC
supplies are unbalanced. The schematic for the circuit is posted in
a.b.s. It's just a basic circuit, it uses a center tapped
transformer
feeding into a full-wave bridge, with the center tap grounded, with a
positive and negative three terminal 12 volt regulator. No rocket
science here. However, the supplies are unbalanced, pretty severely.
The input to the bridge is 14.24 & 14.15 VAC. The output of the
bridge is -25.28 & 10.23VDC with .685 & .240VAC ripple, respectively.
I pulled the board from the unit and powered up each regulator
individually . With -18VDC in across the negative, there was .1A
draw
& -11.90VDC out. With +18V in across the positive regulator, there
was .1A draw & 11.83VDC out, so the reguators are fine and neither
has
excessive current draw down the line. When I put an external supply
across both bridge capacitors I saw the same unbalance. With 35VDC
across the caps, there was 25.94 across the negative cap and 8.99V
across the postitive cap. I connected a capacitor in parallel across
both caps individually, but it didn't create any significant change.
Is it probable that one of the caps is bad causing the unbalance?

Thanks, and I'll provide any more information if necessary.

You can interchange the capacitors to see if the unbalance goes with
the cap. However, it looks to me like you may have an open centre tap,
or the trace between the centre tap and the junction of the caps may
be open.

- Franc Zabkar

The center tap checks good, as well as the trace between center tap to
the capacitor center point. Also, the bridge checks out ok. I guess
I need to pull the regs & put voltage across the caps & see if I have
unbalance then. Also, the caps are different sizes, it looks like
they may have designed the circuit to have higher current out of the
12v reg, which makes perfect sense, I guess the caps could have aged
at different rates then being dramatically different sizes. I'll do
some more testing, thanks for the replies.
Steve

How can you get 25VDC across a cap when the AC supply is only 14Vrms?
The maximum voltage should be only ...

14 x 1.414 = 19.8 - Vf(diode) = 19V

Try desoldering each bridge diode one at a time. That way you'll be
able to test each half of the bridge on its own.

- Franc Zabkar

I'll have to remove the bridge as a whole, it's a four terminal
package. I was using a Fluke 87 III for the measurements. What you
said about the center tap makes sense, that would explain everything,
but it measures fine, .9 ohms between either winding & center, 1.8
total. I'll yank the bridge & caps tomorrow, it can't be too hard to
find, this is a simple circuit for heaven's sake.

Thanks for the posts,
Steve

Definitely a loss of ground reference. I've run into this several times
lately.


Mark Z.

Sorry to dissappoint, but it appears it was bad caps. Actually,
probably just one bad cap, but I replaced both (I don't have a
capacatince meter at home). One is 470uF, the other 2200uF. The
470uF is nested in with a couple of 12ohm 1w resistors, so it was
probably running quite warm. Now oth supplies are balanced within a
volt or so on the input, and the output is regulating beautifully.
Unit powers up & doesn't go into protection. It's an interesting
protection circuit they use. They put equal dividers in all three
supply rails, the +-65V, +-35V, & +-12V. It looks like they are all
summed & fed to a current mirror, and if any drifts off zero the
mirror turns on the protection 2 circuit & shuts down the amp. Maybe
this is common for amplifiers, I just never dug this deep into the
protection circuits before. Usually I deal w/ blown output
transistors or amplifier packs.

Thanks for all the help, I really appreciate it.

Steve

I think you probably fixed the bad ground in the process. A bad cap on one
rail isn't going to make another rail double with respect to ground.

Mark Z.

 

[ian field]

"b" <reverend_rogers@yahoo.com> wrote in message
news:ca23bc28-a03b-49c8-8046-ac3c0ee354cb@w32g2000hsf.googlegroups.com...

I'm repairing a dead philips VR 600, the SB340 diode on one PSU output
gave s/c both directions, I don't have one in my spares box...anyone
know of a suitable equivalent?

datasheet:
http://www.datasheetcatalog.com/datasheets_pdf/S/B/3/4/SB340.shtml

cheers,
B

I googled "3A 40V shottky barrier" and got several results on the first
page.

 

[Dave Plowman (News)]

In article <6kfipkF7n2g4U1@mid.individual.net>,
Geir Holmavatn <geir056@gmail.com> wrote:

I have a three year old Panasonic 32" CRT TV. Does it exist a way to
have it start up in AV input mode and not in tuner mode?

I haven't seen anything in the config menus...

Thanks for tips and comments

If it has SCART connectors 9-12 v applied to pin 8 will force it to that
input at switch on.

--
*Rehab is for quitters

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[William Sommerwerck]

This is not normal, and indicates poor design or something wrong with your
particular sample.

You might try reversing the plug in the wall outlet.

 

[Arfa Daily]

"ian field" <gangprobing.alien@ntlworld.com> wrote in message
news:d0wEk.53884$fd.44490@newsfe12.ams2...

"b" <reverend_rogers@yahoo.com> wrote in message
news:ca23bc28-a03b-49c8-8046-ac3c0ee354cb@w32g2000hsf.googlegroups.com...
I'm repairing a dead philips VR 600, the SB340 diode on one PSU output
gave s/c both directions, I don't have one in my spares box...anyone
know of a suitable equivalent?

datasheet:
http://www.datasheetcatalog.com/datasheets_pdf/S/B/3/4/SB340.shtml

cheers,
B


I googled "3A 40V shottky barrier" and got several results on the first
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

 

[Stacey Chuffo]

<jymb2008@gmail.com> wrote in message
news:aaf1bf2c-8fb8-414a-8544-112b67f7dd3c@m45g2000hsb.googlegroups.com...

On Sep 22, 8:16 pm, "Stacey Chuffo" <phsd-
every...@promisesandiego.com> wrote:
jymb2...@gmail.com> wrote in message

news:8ef97088-adbd-47b4-a93c-91f4179d9abc@25g2000hsx.googlegroups.com...



On Sep 21, 11:40 pm, "Stacey Chuffo" <phsd-
every...@promisesandiego.com> wrote:
"John Bachman" <johnREM...@anatek.REMOVEmv.com> wrote in message

news:h5kdd45lri8lmq7oqm6dqgle0l19ghfkap@4ax.com...

I am shopping for a plasma TV for my mother-in-law and came across a
Dynex which is $200 less than similar sets by known names.

OK, repair guys, what's the scoop on Dynex?

Why even ask a question like that? Did you ever see the picture on a
Dynex?
I did one time at Pest Buy and it was uglier than Ashleigh Cope's
snatch.

When the television needs repair, which is usually about 3 hours after
the
warranty expires on those cheap brands, then forget it, it's not
serviceable
as they do not service them just give you a new one (should one fail
during
the warranty period.)

In the long run, you probably won't be saving $200.00.

TIA

John
AnaTek Corporation
www.anatekcorp.com

It's better than the retarded hate you spew on alt.tv.game-shows

http://groups.google.com/group/alt.tv.game-shows/topics

Now, try and deny that. Bitch.

I wouldn't deny it for a second, bitch. In fact, not only would I not
deny
it, I would tell you why I did it - because Harvey Daye Junior is an
emo-kid-fucking jerkoff and I'll probably do it again. Now if you want to
save $200.00 and buy a cheaper plasma, and teach me a lesson while you're
at
it, then that's your prerogative. Now many people including myself, will
get
turned on by the lower price, just to have the motherfucker fail shortly
after the warranty. They contact the company and spend hours on hold,
that
is only if the company is still in business. Cheaper electronics
manufacturers don't support their products, just replace them if they
fail
under warranty. And after the warranty, fuck it as it is more than
unlikely
any television repairman can repair it. This isn't the case with name
brand
manufacturers which supply parts and service manuals to television
repairmen. So back to the electronics store it is to finally get the name
brand at the higher price, paying more than if you just went with the
name
brand to begin with.

Suck my dick, bitch

Why don't you get Harvey Daye, Jr to suck your dick. You're both in Ohio.

Wait a minute, you are Harvey.

I forgot.

 

[William Sommerwerck]

Obviously, "something" is noisy. (Duh...)

Have you asked the manufacturer?

 

[William Sommerwerck]

"Daniel Rudy" <spamthis@spamthis.net> wrote in message
news:cAHEk.2163$YU2.1183@nlpi066.nbdc.sbc.com...

I've been wondering what electronics magazines are out there these
days. I know about Nuts'n'Volts and Circuit Cellar. And it seems that
Popular Electronics, Radio Electronics, and Electronics Now, that
I used to read when I was in high school, have vanished. Is there
anything good out there these days besides the afore mentioned titles?

MAKE: is not, strictly speaking, an electronics magazine, but it has
electronics projects. You should be warned that its editors have little real
technical knowledge and refuse to acknowledge or correct errors.

Heck, I'm old enough to remember "Electronics World" -- and I still miss it.
It was the only general-circulation electronics magazine that could arguably
be said to be aimed at professionals. (There was also "Electronics", which
was before my time.)

The decline of electronics magazines seems to have been caused by the
falling interest in electronics as a hobby, and by the decline of the US as
a major manufacturer of electronic products. The fact that most electronic
products have become so complex (and cheap to manufacture overseas) that you
can no longer buy kits (Heath, Allied, Lafayette) doesn't help, either.

 

[Geoffrey S. Mendelson]

William Sommerwerck wrote:

The decline of electronics magazines seems to have been caused by the
falling interest in electronics as a hobby, and by the decline of the US as
a major manufacturer of electronic products. The fact that most electronic
products have become so complex (and cheap to manufacture overseas) that you
can no longer buy kits (Heath, Allied, Lafayette) doesn't help, either.

The thing that made Heathkit possible was the large surplus of WWII
electronic components that were obsolete by the time of the Korean war,
but still very useable. Vaccum tube technology lasted in general
electronics well into the 1970's, and discrete components well into
the 1990s.

Now if you want to build something that is not SMT, you have to find old
components, many of which are no longer useable, or have them made for
you because the companies that make current production electronics don't
use them.

Occasionaly I see a copy of Elektor Magazine, which used to be published
in Holland, and is now published in the U.K. The last magazine I saw
was pretty interesting, but all the projects were solder chips on a board
type of project. The days when radios were litterally made on a breadboard
and coils were bell wire wound on lollipop sticks are long gone.

Geoff.

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

 

[TheLogster]

To the person who wrote this -

I would like to commend you. We live in a culture where it is not "PC"
or the "in thing" to talk about God. Society has moved away from not
just belief in God, by also away from the basic teachings of the bible.
I am talking about love, family and community. After all - we are all
God's children.

It can be difficult to introduce such topics to newsgroups and I wanted
to send at least one message that is encourging and not "hate mail".

 

[Christian Treldal]

Den Thu, 27 Oct 2005 08:16:04 +0000. skrev Rikard Bosnjakovic:

I know it is difficult to give a clear opinion only by looking, but what
would be your guess? Could it be only the coil that's toasted, or could it
be any more components? If the latter, how can I find out if that's the case?

Before you change the coil you shoud concider to replace all the
electrotytics, they seems to be bulky and leaking. Dead electrolytics are
a likely reason for the high current drawn. The coil are only for noise
reduction purposes, You can replace it with a jumper or any other coil
with the same wire gauge.

--
Best regards OZ1GNN

Christian Treldal

 

[mike]

Mike Foss wrote:

"mike" <spamme0@netscape.net> wrote in message news:43609ED5.1040705@netscape.net...

Mike Foss wrote:

"mike" <spamme0@netscape.net> wrote in message news:43608FD0.8030000@netscape.net...


do_not_spam_me@my-deja.com wrote:


mike wrote:



Supply and demand.
If your watch kept bad time, you'd send it back.
If your computer keeps bad time, you'll reset the clock
and bitch about it on the internet.


I'm looking for a techical explanation.


Very often, the economic or political considerations
dwarf any technical consideration.
The technical explanation is that they do what's cheap.
Wishing for a grand technical reason won't make it so.
mike


You seem to be saying curiosity is a worthless trait.

Nope, I'm saying insisting on technical explanations for economic
decisions is a worthless trait.
Anybody with a wrist likely understands that it's possible to keep
accurate time. If computer users rated it high in their purchase
decision, you'd see very accurate clocks.


File that one under D for DUH.

The OP was asking for a technical explanation, and so far the
responses have been enlightening. Well, except for yours.


There is no technical explanation except that the technology that

is being used does not guarantee accurate clocks.

If you do the math, you'll uncover the fact that a wristwatch is
phenomenally accurate compared to a RTC crystal.

I haven't been responsible for a computer design since 1989. Back
in the day, the philosophy was, "design for the center of the
statistical distribution and fix it in software."
Fortunately, UINX was smart enough to do time correction.

I haven't been responsible for a frequency counter design group since
1975. Back in the day, the philosophy was, "use the cheapest timebase
that guaranteed the specified accuracy."

I've had motherboards where they saved a nickel by leaving off the two
caps on the Xtal. Adding the caps helped, but "net time" fixed it in
software.

Are we seeing a trend yet?
You can get any accuracy you're willing to pay for. Computer users have
voted with their wallets for "lousy". I don't remember ever seeing a
specification for real time clock accuracy on a motherboard.
So if the clock ticks, it's in spec. Statistically, you'll sometimes
get one that's unacceptable and some of those will get bitched about on
the internet. It's the same reason that sometimes your Ford won't run
right.

You're the Chinese engineer. Go tell the bean counter that you want to
add 20 cents worth of parts to adjust the clock frequency, add $4000
worth of capital equipment to each production station, a week of
additional production line time to setup and program the equipment,
30 seconds of operator time to each board test and decrease the overall
yield.

It really is all about the Benjamins.

Let me restate it in technical terms. You get what you pay for, if
you're lucky.

And yes, my motherboard keeps very good time (but still not anywhere
near as good as my wristwatch). It's not because the design is
different from any other motherboard design. It's because all the
variables conspired to keep good time. I got lucky.

Benjamins!!!

mike

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