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here is how firewire ports fail

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September 1, 2004 10:50:19 PM

Archived from groups: rec.audio.pro (More info?)

this is a copy in its entirity from what M-Audio sent me about firewire
failures

> ³FireWire Port Failures in Host Computers and Peripheral Devices²
>
>  
>
> a White Paper
>
>  
>
> by James Wiebe, CEO
>
> WiebeTech LLC
>
> jameswiebe@wiebetech.com
>
> http://www.wiebetech.com
>
> © 2003 All Rights Reserved
>
>  
>
> This paper may be reproduced, but only in its entirety, and only if credit is
> given to the author and linkage provided to the WiebeTech website.
>
>  
>
> DISCLAIMER
>
>  
>
> The cause of FireWire port failures is extremely complex and this White Paper
> cannot embody all possible failure scenarios or solutions to the problems. 
> The author specifically disclaims any fitness for use of the information
> contained within this white paper. 
>
>  
>
> Port failures are often discussed but remain a relatively infrequent problem,
> especially if the FireWire storage device and the host computer are properly
> designed. 
>
>  
>
> Statistics for total failures of FireWire ports is not known.  Judging from
> the number of posts on Apple¹s website:
>
>  
>
> http://discussions.info.apple.com/WebX?14@103.67TDaKsJj...
>
>  
>
> as well as posts on the website:
>
>  
>
> http://www.macintouch.com/firewirereader02.html
>
>  
>
> this topic is assumed to be of interest to many readers.
>
>  
>
> The author seeks input from anyone who may have additional information which
> can shed light on the subject of this White Paper.  Questions concerning
> particular types of equipment should be directed to the respective
> manufacturer.
>
>  
>
> 1.         INTRODUCTION
>
>  
>
> FireWire allows users to connect storage devices and other peripherals to
> host computers, giving unparalled flexibility in data capture, storage,
> transportation, and backup capabilities.  FireWire allows devices to be hot
> swapped from one computer to another.  Hot swapping allows FireWire storage
> devices (as well as other peripherals, such as video cameras) to be
> physically attached to a FireWire port, automatically mounted on the desktop,
> accessed, and then unmounted / disconnected at the command of the user.
>
>  
>
> The resulting ease of use has caused FireWire technology to be widely
> accepted by millions of users.  FireWire is directly supported by a variety
> of operating systems, including Windows 98SE, ME, 2K, XP and Mac OS9.1, 9.2
> and OSX.  Linux also is capable of supporting FireWire, although the process
> of setting up first use on that platform may be a little more difficult. 
>
>  
>
> Users have reported failures of FireWire ports on host computers after
> attaching FireWire devices to those ports.  This can be quite unsettling to
> the user, since the failure of the FireWire port can be crippling to the
> utilization of the computer.  For instance, it may become impossible to
> create backups or attach FireWire peripherals to the computer after failure
> of the port.
>
>  
>
> The purpose of this report is to provide background and technical analysis of
> the failure of the ports.  In conclusion, methodologies will be suggested
> which may substantially reduce the incidence of damage to host ports.
>
>  
>
> 2.         BACKGROUND INFORMATION ON FIREWIRE OPERATION
>
>  
>
> In order to understand the issue, it is necessary to understand just a little
> bit of how FireWire operates.
>
>  
>
> FireWire allows the attachment of external devices to host computers through
> a cable which is composed of the following wiring components:
>
>  
> € Serial Data Pairs, of which there are two, giving a total of 4 wires.
> € Power, which is generally somewhere between 8 to 24 volts DC.
> € Ground, which is a lead that provides a current return for the Power
> line.
> € Shield, which helps prevent the emission of Radio Frequency
> Interference from the FireWire cable.
>
>  
>
> The Power and Ground lines must be present to allow FireWire devices to be
> bus powered.  For instance, portable FireWire drives usually run off of bus
> power, meaning that they will function when attached to a powered FireWire
> host.  Other types of FireWire devices, such as Desktop FireWire drives,
> usually (but not always) require a separate power supply.  As a result, they
> do not utilize any power from the Power / Ground pair provided by the host
> FireWire port.  They obtain their power from an independent power supply.
>
>  
>
> Manufacturers are not required to provide Power and Ground within the
> FireWire host.  Two different types of commonly used FireWire connectors have
> been defined for FireWire 400 usage.  One of these types is the more common
> six pin connector, while the other type is a physically smaller connector
> which omits Power and Ground.  Obviously, bus powered FireWire devices will
> not work when attached to a FireWire host which does not provide bus power. 
>
>  
>
> Apple computers generally include all of these lines in their FireWire ports,
> while certain PC computers with FireWire capability (such as the Inspiron
> 8200 from Dell or various Sony Vaio laptops) omit the Power and Ground
> lines.  The omission of these lines prevents the use of ³bus-powered² storage
> devices.  This is why portable FireWire drives won¹t work when attached
> directly to PC laptop computers, such as the Dell or Sony models.  No power
> is present on the port.
>
>  
>
> 3.         FIREWIRE FAILURE SCENARIO
>
>  
>
> A typical failure scenario is as follows:  The user attaches a FireWire
> storage device to the computer.  The user expects the device to mount on the
> desktop, but this does not occur.  Repeated attempts to mount the storage
> device (usually by connecting and disconnecting the FireWire cable) produce
> the same results.  Ultimately, the user attempts to mount other FireWire
> devices on the same port without success, and consequently verifies that the
> port is no longer functional.  Various attempts to resolve the situation may
> be attempted, all without success.  This may include machine rebooting,
> Parameter RAM resetting, power disconnection for extended periods of time,
> etc.
>
>  
>
> It¹s worth noting that the host FireWire port may be on the motherboard (as
> is the case for most Apple computers) or it may be on a PCI FireWire host
> adapter card.  The result is the same; the particular port no longer works. 
> The port may still be capable of supplying power to the attached FireWire
> device, but the device is no longer seen on the desktop or in the various
> disk management utilities.
>
>  
>
> The failure of the host¹s FireWire port can produce a very bad day for the
> user.  The knowledge of possible damage (and consequential repair cost /
> hassle) to the computer is compounded by the frustrating inability to mount
> and use external storage devices.
>
>  
>
> 4.         FAILURE CAUSES
>
>  
>
> 4.1       LOSS OF POWER FROM THE PORT
>
>  
>
> What went wrong to cause the failure of the FireWire port?
>
>  
>
> In order to answer the question, let¹s consider the two main functional
> components of the FireWire interface:  the Data lines and the Power lines.  A
> failure mode is the loss of Power through the FireWire port.  A second
> failure mode (which the author believes to be far more likely) is a failure
> of the port¹s ability to supply Data to the FireWire device. 
>
>  
>
> These failure modes cause us to consider:  why would a port lose the ability
> to supply either Power or Data? 
>
>  
>
> In the testing and development of FireWire storage devices, we (WiebeTech)
> have accidentally shorted the FireWire Power / ground lines together many
> times.  This can cause a variety of results:  the immediate shutdown of the
> entire computer system; the shutdown of an individual port; etc.  Apple
> documents that their ports are provided with triple redundant fusing for
> protection against power shorts such as the one just described.  The
> applicable document can be accessed at the following URL, showing FireWire
> specifications on all Apple computers:
>
>  
>
> http://docs.info.apple.com/article.html?artnum=58207
>
>  
>
> The Apple document states:
>
>  
>
> ³Power safety -- The FireWire bus has three self-resetting fuses. If your
> device unexpectedly shuts down, it may be due to an overloaded fuse. If this
> occurs, disconnect the device immediately.²
>
>  
>
> Field experience shows that the power side of the FireWire host port rarely
> fails.  Fuse protection appears to adequately protect the port against most
> problems.
>
>  
>
> 4.2       LOSS OF DATA TRANSMISSION FROM THE PORT
>
>  
>
> The second failure mode is the failure of the port¹s ability to supply Data
> to the FireWire device.  As previously stated, the author believes this to be
> the most common failure mode when FireWire ports fail.
>
>  
>
> FireWire ports within most peripherals are composed of two devices:  the
> FireWire bridge, which connects to the drive and to the FireWire ³PHY², and
> the ³PHY², which connects from the FireWire cable to the FireWire bridge. 
> The PHY receives nearly no mention in most discussion of FireWire devices,
> but it is actually responsible for the electrical connection to the FireWire
> cable, and ultimately, the host device.  The host devices¹ FireWire
> connection is very similar, using a PHY to connect the motherboard
> electronics to the FireWire port.
>
>  
>
> The author has direct experience observing the failure of FireWire ports in
> peripheral devices under developmental test conditions.  This experience
> shows that most port failures occur within the PHY, not in the FireWire
> bridge, and not in the power supply portion of the port. 
>
>  
>
> Post mortem examination of the decapped (plastic removed) failed PHY shows
> gross failure of the circuitry which attaches the Data lines.  After removing
> the plastic package from the integrated circuit, an examination of the
> integrated circuit under a microscope shows clear evidence of electrical
> damage to the part.
>
>  
>
> In other words, something zapped the PHY.  How is this possible?
>
>  
>
> It really wasn¹t supposed to be possible for the PHY to fail.  However, there
> are at many different events which can cause the PHY to fail.  Some of these
> are very easy to understand, while others are a bit more difficult to
> understand.
>
>  
>
> 4.2.1    FAILURE BY ELECTROSTATIC DISCHARGE (ESD)
>
>  
>
> The failure scenario is as follows:  The user inserts a FireWire cable into
> the host.  The user then picks up the other end to attach to the FireWire
> device, and inadvertently discharges ESD through one of the Data lines to the
> host port.  Part destruction occurs.
>
>  
>
> In the real world, this does not (or at least should not) happen frequently. 
> The user is far more likely to discharge through the Shield of the FireWire
> cable, which will dissipate the discharge directly to a ground within the
> host computer, without damaging internal circuitry. 
>
>  
>
> 4.2.2    PORT FAILURE BY BAD CABLE OR BAD INSERTION
>
>  
>
> This failure scenario actually has three sub-scenarios, each of which will be
> described in turn.
>
>  
>
> 4.2.2.1 PORT FAILURE BY REVERSE INSERTION
>
>  
>
> In this scenario, the user inserts the cable with the connector twisted 180
> degrees.  An examination of the FireWire six pin ports suggests that this is
> not possible, but it has actually been done many times.  It is more likely to
> happen when the port is worn, or when the port easily ³spreads² when reverse
> inserted.  Some FireWire ports are built with the metal seam at the narrow
> end of the port, making it much easier to reverse insert the cable.  The
> resulting (errant) electrical connections cause Power lines to be directly
> connected to Data lines.  This invariably fries the PHY attached to that
> port.
>
>  
>
> 4.2.2.2 PORT FAILURE BY BAD CABLE
>
>  
>
> Any internal failure of a FireWire cable which results in Power being shorted
> to a Data line within the cable usually will result in the failure of the
> port to which it is attached.
>
>  
>
> The author was directly told of a typical experience at a major computer
> company.  An employee observed that his FireWire drive would not mount. 
> Suspecting trouble and wanting to verify it, the employee tested the device
> on three more computers.  The device wouldn¹t mount on any of the four
> computers.  The ultimate cause of the problem was a bad cable which fried
> four host ports on the four computers.  The FireWire drive was not at fault. 
> The author assumes that each of the four PHYs was destroyed.
>
>  
>
> 4.2.2.3 PORT FAILURE BY FIREWIRE CABLE TWISTING
>
>  
>
> In this scenario, the user correctly attaches the FireWire cable to the
> computer and the storage device.  A rotational twisting force is applied to
> either connector at either end of the cable, in relationship to the port in
> which it is inserted.  As the connectors are pushed out of position by the
> rotational torque, a short occurs between the Data lines and a Power line,
> resulting in port failure. 
>
>  
>
> 4.2.3    PORT FAILURE BY INDUCED UNDER/OVER VOLTAGE CONDITION
>
>  
>
> This is the scenario which is most difficult to understand.  Essentially, the
> PHY creates or experiences a damaging voltage on one of the Data lines.  This
> error condition is very transient in nature and is caused at startup time of
> bus powered FireWire devices by a bump or droop on a power supply within the
> FireWire device.  The bump or droop is understood through a detailed analysis
> of the actual circuit of the FireWire device, cable, and host port as current
> starts to flow through the Power lines at startup time.  Equivalent circuitry
> must be considered:  IE, inductance within power lines, etc.  (The
> engineering analysis is far beyond the scope of this paper.)
>
>  
>
> As a result, the external FireWire device may briefly experience or transmit
> a damaging voltage to the host computer¹s FireWire port, resulting in the
> destruction of the port.  
>
>  
>
> This failure mode is the one most likely to have created the impression that
> bus powered devices cause FireWire host port failures.
>
>  
>
> 5.         PREVENTING FIREWIRE PORT FAILURE
>
>  
>
> 5.1              OBVIOUS PREVENTATIVES
>
>  
>
> Certain preventive measures seem obvious:
>
>  
> € Always use high quality FireWire cables.
> € If a cable is worn out, replace it immediately.  (Cables used at
> WiebeTech are used heavily throughout every business day; they are
> generally replaced every month, if not more frequently.)
> € Never insert a cable backwards into a port.  If this happens before
> the cable is also attached to the host (or to the peripheral device), get
> the port repaired prior to further use of the device (or host).  Discard
> the cable and use a new one.
> € If a device does not mount, attempt mounting it with a new cable on
> the same port.  Always suspect the cable before suspecting a failure of
> the device.  Try powering the host down; rebooting; etc.  Port failures on
> machines tend to follow the cable.
>
>  
>
> 5.2              PREVENTING PORT FAILURE WHEN USING BUS POWERED DEVICES
>
>  
>
> What follows is three different methods for preventing port failure when
> using bus powered devices.  All require support from the FireWire peripheral
> manufacture and from the host computer.  Other methods are also available ­
> this is not meant to be an exhaustive list.
>
>  
>
> 5.2.1        ESD AND OVER/UNDER VOLTAGE
>
>  
>
> This technique requires installation of protective devices on the FireWire
> port on the host computer.  The protection is installed on the motherboard
> close to the PHY device, with direct connections to the Data lines.  An
> excellent example of how Apple has implemented this technique in certain
> reworked motherboards is found at the following URL:
>
>  
>
> http://www.medicalmac.com/mac98e.html
>
>  
>
> Through proper implementation of this technique, the FireWire port is
> protected against Electro Static Discharge (ESD) as well as problems caused
> by bus powered devices. 
>
>  
>
> The author believes that Apple has been implementing the technique in all
> recent and currently shipping Apple computers.  Suppression of ESD and
> over/under voltage is a primary method of reducing or eliminating port
> failure and must be implemented on the host computer to be effective.
>
>  
>
> 5.2.2    VOLTAGE TRANSIENT SUPPRESSION CIRCUITRY ON BUS POWERED DEVICES
>
>  
>
> WiebeTech has implemented a proprietary technique which prevents transients
> at power on time from being transmitted to the host computer via the Data
> lines.  This resolves issues related to use of bus powered devices.  This
> technique has been used with excellent results in WiebeTech¹s bus powered
> FireWire DriveDock devices, which are capable of bus powering 3.5 inch IDE
> hard drives. 
>
>  
>
> 5.2.3        THE USE OF A POWER SWITCH IN BUS POWERED DEVICES.
>
>  
>
> WiebeTech recommends the use of power switches in bus powered FireWire
> devices.  This prevents the PHY within the FireWire device from transmitting
> voltage transients through the FireWire cable to the PHY on the motherboard
> of the host computer.  Simply put, the FireWire device is not powered up
> until all connections have been made and voltages have had a chance to
> stabilize.  This technique is used on WiebeTech¹s portable drives, including
> the MicroGB+; MicroGB+Combo; and 3.5 inch bus powered UltraGB.
>
>  
>
> 5.2.4        CURRENT LIMITING OF POWER ON TRANSIENTS
>
>  
>
> WiebeTech has also implemented a technique which allows the power supply of
> the FireWire device to ³soft start² while the device is still in the off
> position.  This is implemented in WiebeTech¹s UltraGB 3.5 inch bus powered
> drive.  The UltraGB has a three position switch:  Bus Power ­ Off ­AC Power. 
> When the Off position is selected AND when the device is attached to a host
> through a FireWire cable, the internal power supply ramps up to voltage
> through a current limiting circuit into a power storage circuit.  This
> provides important benefits:  a substantial amount of power may be ³saved
> up², helping large drives to spin up successfully; and power on transients
> are filtered through the current limiter, substantially reducing bumps and
> droops in the power supply.
>
>  
>
> 5.3       OTHER METHODS OF RESOLVING HOST PORT FAILURES
>
>  
>
> 5.3.1        REPAIR THE MACHINE
>
> If the user has a computer under warranty, it is likely that the manufacturer
> will repair the damaged port without charge of any kind.  It may be
> worthwhile checking with the manufacturer, even if the computer is out of
> warranty.
>
>  
>
> 5.3.2    ADD AN INEXPENSIVE FIREWIRE HOST CARD
>
>  
>
> If the machine is out of warranty and has available PCI slots, the simplest
> way to repair the computer is to add a FireWire PCI card.  They are
> inexpensive and very easy to install.  Most operating systems do not require
> the installation of any additional software drives to support FireWire usage
> through a PCI card.
>
>  
>
> 6.                  CONCLUSIONS
>
>  
>
> Most of the failure modes of FireWire ports are believed to be caused by low
> quality or worn out FireWire cables, operator error during device and cable
> insertion, inadequate PHY port protection, and improper design of external
> FireWire devices which causes voltage surges to the host port.
>
>  
>
> 6.1       CABLE PREVENTATIVES
>
>  
> € Users are encouraged to use high quality FireWire cables.
> € Users are encouraged to replace worn out FireWire cables.
> € Never plug a FireWire cable in backwards (although it seems
> impossible; it¹s been done many times.)
> € Don¹t apply twisting torque to cables that are inserted into sockets.
> € If a device doesn¹t mount, do not test the cable on another machine.
>
>  
>
> 6.2              HOST PORTS
>
>  
> € Older computers may not have FireWire port protection built into
> them.  This appears to place them at higher risk of failure.
> € Recently manufactured computers are likely to have enhanced port
> protection.
> € If your port fails while the computer is within warranty, you won¹t
> have any problems getting it repaired.
> € If your port fails while the computer is out of warranty, an
> inexpensive solution is to use a low cost PCI FireWire host card.  
> (assuming you have open slots).
>
>  
>
> 6.3       FIREWIRE PERIPHERALS
>
>  
> € FireWire Peripherals should have a transient limiting circuitry on the
> Data lines at power up time, in order to prevent transients from causing
> damage to the host¹s PHY.
> € An alternative method is to use FireWire devices that are turned on
> via switch after attachment to the FireWire cable.
> € Another method is to use FireWire peripherals with built in inrush
> current limiting on the Power lines.
> € Always follow the attachment and power up recommendations of your
> host and peripheral manufacturer!
>
>  
>
> The author hopes this material has been helpful in shedding light on the
> issue of FireWire port failures.
>
>  
>
> © 2003 WiebeTech LLC, All Rights Reserved.  FireWire
>
>  
>
>  
>
>  
Thank you to those who made this available
George

More about : firewire ports fail

Anonymous
September 2, 2004 3:40:38 PM

Archived from groups: rec.audio.pro (More info?)

A client brought in a Firewire HD (and his own cable) and fried the firewire
port on my G4 last summer. Though he bought me a PCI firewire card, he never
*really* accepted responsibility. I forwarded him the weibetech post. Thanks
for posting it.


Joe Egan
EMP
Colchester, VT
www.eganmedia.com
September 2, 2004 4:22:08 PM

Archived from groups: rec.audio.pro (More info?)

In article <20040902074038.15331.00000115@mb-m22.aol.com>,
eganmedia@aol.com (EganMedia) wrote:

> A client brought in a Firewire HD (and his own cable) and fried the firewire
> port on my G4 last summer. Though he bought me a PCI firewire card, he never
> *really* accepted responsibility. I forwarded him the weibetech post. Thanks
> for posting it.
>
I find it astounding they accept having to replacethe 20$cable every
month,granted thier cable most likely would be abused more than mine
that only hooks and unhooks a few times each monh
but still that is a huge problem if the cableing is that suspect and if
you make a mistake about when to buy a new cable you will take out your
computer and possibly the fw device in the process
Related resources
Anonymous
September 2, 2004 5:10:20 PM

Archived from groups: rec.audio.pro (More info?)

In article <g.p.gleason-524324.08220902092004@netnews.worldnet.att.net> g.p.gleason@worldnet.att.net writes:

> I find it astounding they accept having to replacethe 20$cable every
> month,granted thier cable most likely would be abused more than mine
> that only hooks and unhooks a few times each monh
> but still that is a huge problem if the cableing is that suspect

The real problem is that that port isn't adequately protected against
electrical mishaps. The cable and connector just happen to be weak
points. This is typical of disposable equipment designed for consumer
use.

In straight audio, it goes back at least as far as the RCA jack. You
could blow a speaker or something else by 'hot plugging' an RCA cable
because the ground connection wasn't made first, exposing a sensitive
input to a nice hum source.




--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
September 2, 2004 9:18:40 PM

Archived from groups: rec.audio.pro (More info?)

In article <znr1094132739k@trad>, mrivers@d-and-d.com (Mike Rivers)
wrote:

> In article <g.p.gleason-524324.08220902092004@netnews.worldnet.att.net>
> g.p.gleason@worldnet.att.net writes:
>
> > I find it astounding they accept having to replacethe 20$cable every
> > month,granted thier cable most likely would be abused more than mine
> > that only hooks and unhooks a few times each monh
> > but still that is a huge problem if the cableing is that suspect
>
> The real problem is that that port isn't adequately protected against
> electrical mishaps. The cable and connector just happen to be weak
> points. This is typical of disposable equipment designed for consumer
> use.
>
> In straight audio, it goes back at least as far as the RCA jack. You
> could blow a speaker or something else by 'hot plugging' an RCA cable
> because the ground connection wasn't made first, exposing a sensitive
> input to a nice hum source.
>
I think I'd like to know how to disable the power on the firewire port
and just run my wall wart to my 410

it would seem to me if I can remove the juice from the cable the problem
would really just simply not exist
I doubt data alone could blow out the interface
George
Anonymous
September 3, 2004 5:48:29 AM

Archived from groups: rec.audio.pro (More info?)

On Thu, 02 Sep 2004 17:18:40 GMT, George
<g.p.gleason@worldnet.att.net> wrote:

>>
> I think I'd like to know how to disable the power on the firewire port
>and just run my wall wart to my 410
>
>it would seem to me if I can remove the juice from the cable the problem
>would really just simply not exist
>I doubt data alone could blow out the interface
>George

Considering the minimal cost of a pci firewire card, are you that
worried?

CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm
"Possibly the world's least impressive web site": George Perfect
September 3, 2004 7:02:51 AM

Archived from groups: rec.audio.pro (More info?)

In article <1qffj01a9pi69l0dk66thv87l2fbddhecb@4ax.com>,
Laurence Payne <l@laurenceDELETEpayne.freeserve.co.uk> wrote:

> On Thu, 02 Sep 2004 17:18:40 GMT, George
> <g.p.gleason@worldnet.att.net> wrote:
>
> >>
> > I think I'd like to know how to disable the power on the firewire port
> >and just run my wall wart to my 410
> >
> >it would seem to me if I can remove the juice from the cable the problem
> >would really just simply not exist
> >I doubt data alone could blow out the interface
> >George
>
> Considering the minimal cost of a pci firewire card, are you that
> worried?
>
I am on a G4 titanium laptop
I dont think the cards fit.
George
Anonymous
September 3, 2004 2:44:45 PM

Archived from groups: rec.audio.pro (More info?)

In article <1qffj01a9pi69l0dk66thv87l2fbddhecb@4ax.com> l@laurenceDELETEpayne.freeserve.co.uk writes:

> Considering the minimal cost of a pci firewire card, are you that
> worried?

Considering the substantial cost of a laptop computer, maybe he is.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
!