Toshiba TV29C90 problem; Image fades to black...

[kony]

On Wed, 24 Aug 2005 04:12:33 GMT, SMS
<scharf.steven@geemail.com> wrote:

kony wrote:

HOWEVER, it is not common for them to do so when it requires
reworking the inner layer. If they do not rework the inner
layer, there is no point to having these surface mount pads,
as the inner layer is always a closed (sub)circuit and
nothing done (whether open or closed, populated) with these
surface mount supply lines makes a difference.

Changes to the power and ground layers are much simpler than changes to
the signal layers.

In many situations it may be true, but much, much simpler is
to not change any of the layers.

No need to change the masks for the signal layers
when you can just not populate some components.

True, not populate components instead of changing layers.

It's hard to believe that building two different versions of a board is
more economical than just putting in a jumper or a fuse. But often the
board without the fuses has other differences. It will be made out of a
cheaper material as well.

It cannot be concluded that "it will be made out of a
cheaper material" based on this alone. It is possible that
some are made of cheaper material, but likewise possible
that they are not made of cheaper material. Whether there
is a fuse or not is no evidence of it at all.

So it's no big deal to make a minor change to
the masks for the power or ground layer, in fact the change can be made
manually. But there is no reason to change the signal layer masks to
remove the pads for the fuse, or the silkscreen.

This is a generalized concept, not any evidence that any (PC
motherboards) are currently produced this way.

In fact, the vast majority are definitely not produced this
way. If the fuse is omitted they're jumpered, or the
surface pads are cotinuous by having a connecting track
between them. This is a standard practice and can be
observed on any motherboard without a fuse. This is quite
specifically why the whole thread exists, because if this
method is not being used on this specific board, it is an
exception to the rule.

 

[Noozer]

"kony" <spam@spam.com> wrote in message
news:5cjog1lmbo3dqfu259guatthsak6eunc5a@4ax.com...

On Wed, 24 Aug 2005 04:12:33 GMT, SMS
scharf.steven@geemail.com> wrote:

kony wrote:

HOWEVER, it is not common for them to do so when it requires
reworking the inner layer. If they do not rework the inner
snip

Isn't this thread dead yet???

Whenever possible, MB makers produce one board and then only add components
to support the features of a specific model.

It's cheaper to make 10,000 of one board than 2,000 of five different
boards.

It also means that the manufacturer can produce more with a specific feature
if it tends to sell better and leave off features that don't add value for
the customers.

 

[kony]

On Wed, 24 Aug 2005 12:01:46 GMT, "Noozer"
<dont.spam@me.here> wrote:

"kony" <spam@spam.com> wrote in message
news:5cjog1lmbo3dqfu259guatthsak6eunc5a@4ax.com...
On Wed, 24 Aug 2005 04:12:33 GMT, SMS
scharf.steven@geemail.com> wrote:

kony wrote:

HOWEVER, it is not common for them to do so when it requires
reworking the inner layer. If they do not rework the inner
snip

Isn't this thread dead yet???

Heh, I'm arguing based more on principle now than any other
reason. We have posters making a guess, then trying to
conclude that (what is possible) is evidence... without any
examples, and without consideration of any other
possibilities.

Whenever possible, MB makers produce one board and then only add components
to support the features of a specific model.

It's cheaper to make 10,000 of one board than 2,000 of five different
boards.

I agree. They're absolutely not going to rework layers even
a tiny bit when a simple surface mount component will do.

 

[Ken Weitzel]

kony wrote:

On Wed, 24 Aug 2005 12:01:46 GMT, "Noozer"
dont.spam@me.here> wrote:


"kony" <spam@spam.com> wrote in message
news:5cjog1lmbo3dqfu259guatthsak6eunc5a@4ax.com...

On Wed, 24 Aug 2005 04:12:33 GMT, SMS
scharf.steven@geemail.com> wrote:


kony wrote:


HOWEVER, it is not common for them to do so when it requires
reworking the inner layer. If they do not rework the inner

snip

Isn't this thread dead yet???



Heh, I'm arguing based more on principle now than any other
reason. We have posters making a guess, then trying to
conclude that (what is possible) is evidence... without any
examples, and without consideration of any other
possibilities.


Whenever possible, MB makers produce one board and then only add components
to support the features of a specific model.

It's cheaper to make 10,000 of one board than 2,000 of five different
boards.


I agree. They're absolutely not going to rework layers even
a tiny bit when a simple surface mount component will do.

Hi...

Hey, your arrogance has reached a level of hilarity. Maybe
a new reality show should be considered. "Who's in charge
of safety certification for every country in the world"

Then again, we know that you are; perhaps you just need
to have your staff send out an official letter to the heads
of UL, CSA, and all the worldwide rest informing them that
you are in charge of how things are to be done?

Ken

 

[Jasen Betts]

In article <1124432882.979924.40630@g47g2000cwa.googlegroups.com>, larry moe 'n curly wrote:

This is the first time I've seen a mobo made for fuses where the
left-out fuses weren't substituted with jumper wires (PC Chips, some
ECS) or copper traces between each fuse location's solder pads.

sometimes they use "zero ohm" surface mount resistors,
or possibly even surface mount fuse-resistors?

Bye.
Jasen

 

[SMS]

kony wrote:

In fact, the vast majority are definitely not produced this
way. If the fuse is omitted they're jumpered, or the
surface pads are cotinuous by having a connecting track
between them. This is a standard practice and can be
observed on any motherboard without a fuse. This is quite
specifically why the whole thread exists, because if this
method is not being used on this specific board, it is an
exception to the rule.

The low end boards reduce costs in every possible way. They may be using
non-UL approved PC board material, and are probably omitting every
non-essential component. They are probably stuffing the minimum number
of bypass capacitors, using the "remove capacitors one at a time until
the board fails, then add one back" method. This would be the type of
board where they would change the power layer to supply +5V power
directly to the ports, eliminating the expense of a fuse or jumper, or
of adding a trace. There are probably traces going under the fuse, which
would make it impossible to add a connecting trace without a board
relayout, which is very costly.

I worked for the 2nd largest motherboard company (at the time) and we'd
do anything reasonable to save a couple of cents per board, including
changes to PCB layers, if the volume was high enough.

 

[kony]

On Wed, 24 Aug 2005 13:57:26 GMT, Ken Weitzel
<kweitzel@shaw.ca> wrote:

I agree. They're absolutely not going to rework layers even
a tiny bit when a simple surface mount component will do.

Hi...

Hey, your arrogance has reached a level of hilarity. Maybe
a new reality show should be considered. "Who's in charge
of safety certification for every country in the world"

Then again, we know that you are; perhaps you just need
to have your staff send out an official letter to the heads
of UL, CSA, and all the worldwide rest informing them that
you are in charge of how things are to be done?

Is that a trolling attempt or are you simply ignorant of the
fact that there is zero need to change layers for any safety
certification?

I never claimed anything remotely near a disregard for any
local certification, as any market the product is targeted
towards will have such accomodations engineered into it, NOT
re-engineering internal layers every time.

 

[kony]

On Wed, 24 Aug 2005 14:48:46 GMT, SMS
<scharf.steven@geemail.com> wrote:

kony wrote:


In fact, the vast majority are definitely not produced this
way. If the fuse is omitted they're jumpered, or the
surface pads are cotinuous by having a connecting track
between them. This is a standard practice and can be
observed on any motherboard without a fuse. This is quite
specifically why the whole thread exists, because if this
method is not being used on this specific board, it is an
exception to the rule.

The low end boards reduce costs in every possible way.

Yes, but that is certainly NOT always done by re-engineering
or parts substitutions when they also had a more elaborate
or more stringent certification necessary for other global
regions. This is quite evident with many boards.

They may be using
non-UL approved PC board material, and are probably omitting every
non-essential component.

No, not every... you're guessing. Even junky, lowest of the
major low-end PCChips boards have a few SMD caps, resistors
and such going to ports whose physical sockets weren't
installed.

They are probably stuffing the minimum number
of bypass capacitors, using the "remove capacitors one at a time until
the board fails, then add one back" method.

Yes they do reduce capacitor counts or quality in "some"
designs. This is not new, but cannot be assumed to apply in
many cases, either... the boards themselves are the proof,
we need not overgeneralize when there are so many concrete
proofs of these things.

This would be the type of
board where they would change the power layer to supply +5V power
directly to the ports, eliminating the expense of a fuse or jumper, or
of adding a trace.

No, absolutely not. If the upper pads on the top layer are
those for the port/features supplied (working) on a
particular board, they do MOST DEFINITELY NOT just go and
rework the inner layer. How hard is this to grasp? Look at
some boards. I don't mean to be rude about this, but you're
overgeneralizing to the point where the resulting logic is
in error and it's useful to see why that's the case.

It is obvious that with the traces already in place, if
there were to be any cost-reduction in layer rework, the
very most they would do is bridge the two solder pads, for
several reasons. A couple - Power traces (rather than large
planes) should not be in inner layers when fine signal lines
are above them (as the port data lines are). They heat up
more and could delaminate, plus cheap boards tend to have
only 4 layers, no ground layer between these so you would
have the potential for noise pickup.

There are probably traces going under the fuse,

You are again jumping to conclusions. We cannot assume
"probably", and with all the hundreds (if not more)
resistors and caps surface mounted, it is rather trivial to
put a 0 ohm resistor across the pads. To even think about
doing it any other way costs more than just doing it the
same way as (ironically enough) everybody has been doing it.

which
would make it impossible to add a connecting trace without a board
relayout, which is very costly.

Still you are drifting along with ideas based around
erroneous conclusions. What they do, put simply:

The entire board is designed, period. They do not rework
the layers. Surface mounted pads are used, populated for
differing compliance and features. This is the way it IS
done. Look at some boards. No, look at ALL boards. This
is the way it is done. "IF" the board the OP observed, the
board that started this whole thread, deviates from this, it
is unique in this regard.

However, we still have no evidence that these missing
components/pads are actually supply for the implemented
ports on that board, rather than there being another
trace(s), on the surface layer, for power.

I worked for the 2nd largest motherboard company (at the time) and we'd
do anything reasonable to save a couple of cents per board, including
changes to PCB layers, if the volume was high enough.

Sure, if there was justification, a way to do so it could be
done for some things. That's not evidence that this is
what's happening to modern motherboards for port power
traces. The motherboards themselves are evidence.

 

[Franc Zabkar]

On Wed, 24 Aug 2005 14:48:46 GMT, SMS <scharf.steven@geemail.com> put
finger to keyboard and composed:

kony wrote:


In fact, the vast majority are definitely not produced this
way. If the fuse is omitted they're jumpered, or the
surface pads are cotinuous by having a connecting track
between them. This is a standard practice and can be
observed on any motherboard without a fuse. This is quite
specifically why the whole thread exists, because if this
method is not being used on this specific board, it is an
exception to the rule.

The low end boards reduce costs in every possible way. They may be using
non-UL approved PC board material, and are probably omitting every
non-essential component. They are probably stuffing the minimum number
of bypass capacitors, using the "remove capacitors one at a time until
the board fails, then add one back" method. This would be the type of
board where they would change the power layer to supply +5V power
directly to the ports, eliminating the expense of a fuse or jumper, or
of adding a trace.

I'm in no position to dispute this, but I'm finding it very hard to
accept. Have you actually witnessed this?

There are probably traces going under the fuse, which
would make it impossible to add a connecting trace without a board
relayout, which is very costly.

I worked for the 2nd largest motherboard company (at the time) and we'd
do anything reasonable to save a couple of cents per board, including
changes to PCB layers, if the volume was high enough.

Have you any idea why the third [open] fuse is there?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Franc Zabkar]

On 18 Aug 2005 12:03:17 -0700, "larry moe 'n curly"
<larrymoencurly@my-deja.com> put finger to keyboard and composed:

Conor wrote:
In article <1124355840.478272.157770@g44g2000cwa.googlegroups.com>,
larry moe 'n curly says...

Yes, but why specifically is the circuit board laid out for those
fuses?

Fuck sake...you really have no idea do you?

It is far cheaper for manufacturers to design and stock one PCB to work
across many models than to design and make a PCB for each individual
model.

I realize that, but in this case I can't imagine why the manufacture
would vary the design because the fuses are for keyboard (and maybe
mouse), USB, and Ethernet, and this particular mobo doesn't seem to
have any missing features for these because it does allow wake on
keyboard/mouse/USB/Ethernet.

The only missing feature I can think of that requires +5V power is a
firewire port. If there is no real estate set aside for a firewire
chip on the motherboard, perhaps it is intended as a future addition
to the Via chipset ??? Is there an unpopulated location for a firewire
connector?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[larry moe 'n curly]

Franc Zabkar wrote:

The only missing feature I can think of that requires +5V power is a
firewire port. If there is no real estate set aside for a firewire
chip on the motherboard, perhaps it is intended as a future addition
to the Via chipset ??? Is there an unpopulated location for a firewire
connector?

This mobo is an Asrock (Asus) K7VTA Pro rev. 1.02. I don't know if its
chipset supports firewire, but there don't seem to be any unused pads
that could be used for an optional firewire connector. Also I was
wrong about the number of fuses: There's a place for a fourth fuse, in
front of the first PCI slot, near the SATA connectors. One pad
measures 5V, the other is probably floating because while there's 0V
across the pads there's also 0V between that pad and ground. Near each
missing fuse are some missing small components, most labelled as
resistors or capacitors, others unlabelled.

This is my first experience with Asrock, so I don't know if the mobo is
high quality or not, but unlike some ECS and PC Chips mobos where all
the electrolytic capacitors are a Taiwanese brand, like OST, some of
the caps around the CPU voltage regulator seem to be Japanese because
they're brown and labelled "KZT", which I've read is United Chemi Con.

 

[mar vrba]

Fran?ois Revol Wrote:

I recently got an umax scanner that was going to trash.
The stepper motor controller chip seems to have burnt.
It's a TI, but that's quite all I know about the reference.
I mailed the umax support, but got no reply, I don't
think they care that much.
Anyone has an umax astra 2000P (maybe other refs have
the same board) and could tell me the IC ref of U3 on
the main board marked:
HAIO M/B 2000P (+SHUTTLE) REV:B P/No: 5100011-0003 9913

Cheers,
François.

____________
here are numbers of chips I found on *MY* M/B:

[1] EK9840V; TCC099916
[2] UT51C164JC-35; 9934
[3] 130 100 56; -5011; 9936E
[4] H E; 7805; 9ER A
[5] LB1233; 8S6

the number of cable is:

[1] FUJIKURA-R; RU AWM; 2896; 80C; VW-1


there are, in UMAX ASTRA 2000P (P=Parallel port), total 3 printed
circuits, should I write You the number of chips located on the other
2?

I am interesting in materials about UMAX ASTRA 2000P.
[: Could You send me, if You have some, please? :]

mar vrba (xxxxx0{at}centrum{dot}cz)

P.S.: But the id of *MY* M/B differs a bit, it is:
HAIO M/B 2000P (+SHUTTLE) REV:C P/NO:510 000 11-000 4


--
mar vrba

 

[Dave xxxx]

blaildyors@quassouwko.mailexpire.com wrote:

I am trying to find a source for a piezo tweeter (I believe it may
be
made by motorola) KSN1020A or KSN1075A (6-50KHz, 50W) or equivalent
in
the UK or someone who will ship to UK. If equivalent, upper
frequency
response needs to be >40KhZ.

Cheers,
Dave

http://www.wagner.net.au/pae/Data/CTS/piezoelectric_speakers.pdf


http://www.nowcomponents.com/item1/page.cfm/2036




--
Dave
www.davewhitter.myby.co.uk

Music is Art - Audio is Engineering
Steam is Fun

 

[Raymondj]

I also have a Kenmore induction cooktop that has bad T30G40
transistors. Has anyone found where to buy them? I need ten in case
someone wants to put a large order to a distributor, and offer to
resell them to end users like me.

Raymond

 

[Franc Zabkar]

On 12 Sep 2005 17:05:54 GMT,
rramirez@prtcmail.prtc-dot-net.no-spam.invalid (Raymondj) put finger
to keyboard and composed:

I also have a Kenmore induction cooktop that has bad T30G40
transistors. Has anyone found where to buy them? I need ten in case
someone wants to put a large order to a distributor, and offer to
resell them to end users like me.

Raymond

Here are the specs:
http://www.datasheetarchive.com/semiconductors/specsheet.php?specsheet=2032248

Part Number = T30G40
Description = Si NPN Power Bipolar Junction Transistor
Manufacturer = Shindengen
V(BR)CEO (V) = 400
V(BR)CBO (V) = 800
I(C) Abs.(A) Collector Current = 30
Absolute Max. Power Diss. (W) = 200
h(FE) Min. Static Current Gain = 80
f(T) Min. (Hz) Transition Freq = 7.0M
t(d) Max. (s) Delay time. = 3.0u
t(s) Max. (s) Storage time. = 3.0u
t(f) Max. (s) Fall time. = 1.0u
Package = SIP
Military = N

B&D Enterprises (http://www.bdent.com/distributors/shindingen.jsp)
is/was a Shindengen distributor, but this part is not listed on their
site. They may still be worth a try, though.

-- Franc Zabkar

Please remove one 'i' from my address when replying by email.

 

[Donha]

Do you still have a Tektronix 502A Dual beam Oscilloscope for sale?

 

[dpatel]

bwrote:
chris@hemingwayc.freeserve.co.uk wrote:
Dear all

After a while switched on my Philips TV switches itself off and the
power light starts flashing red. To get it back on again, have to
switch it off manually, wait for a bit then switch on - and you can
hear a ling or tick-tick sound as if its struggling to power
up.
Saw a similar post which mentioned this was probably a power problem
so
protection circuit had cut in. Have accessed service menu with
following results;

Date: Sep 25 2000 Id: MG21E13.5_02591
Operation hours: 03882.0
Errors 067 068 067 068 067 068 067 068 067 068
Defect. Module: +8V Supply

Can someone with a manual tell me what these error codes are more
specifically and how to fix it.

Thanks

i assume you have first done 'the obvious', like checking for dry

joints round the line drive, HOT, vertical ic etc. and replaced the
electrolytic caps in the psu?
-B.

Chris

[/quote]
tell me if you have fixed this fault if not some one told me to
replace the relay 1010 .. i have not yet done this ...

Dev

 

[simona2001]

Thanks for replying Geoff.

I have followed your instructions but when I reassemble the loading
mech and power on and select a tray to open, tray 1 slides back and I
can hear the motors trying to turn but the mechanism jams and ejects
tray 2, I've never seen the mechanism raise tray 3.

If you could send me a copy of the diagrams I would be very grateful, I
can't see a way of mailing you direct on these forums?

Simon.


--
simona2001

 

[Doug Miller]

In article <eSLXe.9183$fb6.2357@trnddc08>, "James Sweet"
<jamessweet@hotmail.com> wrote:

You can't use the fence controller itself as they normally shut down
when the
loop is open and you need it connected to only one end so the signal
will
not be present after the break.

Entirely incorrect. At least with respect to the Invisible Fence

brand,
anyway. It does *not* shut down on an open loop, you do not need it
connected
to only one end, and the discontinuity in the signal is *clearly*
evident. I
just had to trace a break last week; the AM radio showed very strong
signals
all the way along the wire, which abruptly stopped *directly* over the
break.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

 

[Bob Kos]

<esoroka@gmail.com> wrote in message
news:1117844049.979105.188200@g47g2000cwa.googlegroups.com...

Anybody know the difference between the words:
a) Refurbished
b) Reconditioned
c) Remanufactured
d) Rebuild


Thanks,
Eugene

Refurbished - an overused term that has come to define an item that is used
and tested operational at this time. It used to mean repaired at a factory
or ASP level after the item failed DOA or nearly new. Now the term applies
to anything that is used and happens to be still working and that proper
operation has been assured by the seller. It's all B.S.