1. This forum section is a read-only archive which contains old newsgroup posts. If you wish to post a query, please do so in one of our main forum sections (here). This way you will get a faster, better response from the members on Motherboard Point.

Schematics for HP/Compak NX9110 Notebook Main Board

Discussion in 'Laptops' started by Alf Katz, Nov 18, 2006.

  1. Alf Katz

    Alf Katz Guest

    I have a dead HP/Compak NX9110 laptop. Of course HP have quoted a new
    motherboard price that is higher than the value of the laptop.

    After investigating a ~3 Hz ticking sound, I have narrowed the problem down
    to a MAX1902 multiple output switching regulator which regulates the 3V and
    5V supplies. Nice looking device really. It looks like the device is being
    shut down via the Time/ON5 input. However, I can't see what is driving this
    input (naturally it's a multilayer board making further diagnosis

    It doesn't seem to be going into current limit, or tripping either the
    overvoltage or undervoltage circuits.

    What would really help is a mainboard schematic. Does anyone have one they
    can scan, or know where to find one?

    Alf Katz, Nov 18, 2006
    1. Advertisements

  2. Alf Katz

    zwsdotcom Guest

    You'll never find one; these devices are not serviceable at the
    component level and all accessible documentation will, at best, give
    you only a subassembly-level guide.

    In many cases, if you have standby voltage present on the board and it
    won't fully power up for some reason, the signals in question will
    trace back to a slave micro that manages power and other misc.
    functions. It's usually an 8-bit micro. In modern machines this is
    often an all-in-one chip containing the keyboard and pointing device
    interface also. Often the "no switch on" decision is being made
    internally to that slave micro based on other inputs, the state of
    which you have to infer.

    I'd try hotwiring the regulator "on" and see what happens - given that
    the board is garbage already. However I've rarely been successful at
    fixing component-level problems on laptop mainboards; without design
    intent information, everything has to be analyzed from first principles.
    zwsdotcom, Nov 18, 2006
    1. Advertisements

  3. Schematics don't exist outside of the development engineering
    organization. Even the service manuals don't have them.
    Barry Watzman, Nov 19, 2006
  4. Alf Katz

    BillW50 Guest

    A company named SAMS used to reverse engineer electronic devices and
    then make a schematic for it as well. I recall they did this for many
    computers back in the 80's. I don't know if they are still around. As
    they went back for decades for TVs and radios. I should still have my
    SAMS schematics for my Commodore VIC-20. I have my Commodore SX-64
    (first color luggable) schematics straight from Commodore themselves.
    Ah... things isn't like this anymore, eh?
    BillW50, Nov 19, 2006
  5. Alf Katz

    zwsdotcom Guest

    Technology to do this has become much easier. There's software now that
    will take as input standard X-rays of a PCB and create a netlist from
    that more or less automatically.

    The reason it's not done commercially any more is because the
    information is useless. 99% of the time even if you can work out which
    part is actually faulty, this merely leads you to "Replace ASIC that
    isn't available off the shelf". And the debugging time, at $85 per hour
    or more, rapidly approaches the $500 cost of a new machine.
    zwsdotcom, Nov 19, 2006
  6. Alf Katz

    Bert Guest

    Hello Bill
    Do you have by any chance a circuit diagram for the English made Commodore
    I have 3 faulty C64 and one complete working and one without sound.
    Want to tackle them sometime in the future.
    Bert, Nov 19, 2006
  7. You are talking about "Sams Photofacts", and they were not reverse
    engineered, they were based on information voluntarily supplied by
    manufacturers. They were the source of information used by repair shops
    for TVs, radios, stereos and car radios. They did some computers and
    some monitors back in the 1980's.

    They've been around since 1946 and are still in business:


    But you won't find schematics of laptops, in fact I don't think you will
    generally find computers at all.
    Barry Watzman, Nov 19, 2006
  8. Alf Katz

    Ben Myers Guest

    In all the years I've been dealing with Wintel personal computers and notebooks,
    I have never seen a vendor-supplied schematic for a board. The best one can
    hope for is a very good service manual with decent drawings showing how to take
    apart a notebook, the order of removing things, and drawings of photos of
    individual parts. Dell and IBM/Lenovo have been consistently good at providing
    such info. HPaq not quite so good, but I have gotten a few Compaq notebook
    service manuals. Ditto Gateway/eMachines. But then Toshiba and Sony provide
    nothing at all to the consumer in the way of system maintenance info... Ben
    Ben Myers, Nov 19, 2006
  9. Alf Katz

    BillW50 Guest

    Really? Sams Photofacts claims reversed engineering like I said.

    *** PHOTOFACT® is recognized as the world's best and most accurate
    service documentation available today. For over 55 years, Sams has used,
    and continues to use, a process called "reverse engineering" to create
    Photofact. Reverse Engineering is a process in which the equipment is
    disassembled and each component and circuit is checked and documented.
    Each Sams schematic is drawn accurately in a consistent, standardized
    format which makes it easy to use and simple to understand. ***
    BillW50, Nov 19, 2006
  10. Alf Katz

    BillW50 Guest

    I have the service manual for a Commodore SX-64 in storage, which is
    electronically the same. But 8-bit computers like the Commodores are
    easy to repair even without a schematic. See:


    No sound is usually the SID chip, 6581
    BillW50, Nov 20, 2006
  11. Alf Katz

    BillW50 Guest

    Yeah I know, isn't that something? I started having trouble when things
    came out with muli-layer boards. I guess it is called progress! :(
    BillW50, Nov 20, 2006
  12. Alf Katz

    APR Guest

    Still being done ... see the experts... http://www.bomarc.org/
    APR, Nov 21, 2006
  13. Alf Katz

    BillW50 Guest

    Hahahaha... I have some Roswell control panels I need to have reversed
    engineered. They sound perfect. Thanks again! :D
    BillW50, Nov 21, 2006
  14. Alf Katz

    zwsdotcom Guest

    Not quite. No sound is often the power supply. The only things on the
    C64 board that require the 9VAC are the audio and a passthrough to the
    user port. Not all flavors of the C64 PSU put out 9VAC, so mixing and
    matching the PSUs can lead to no sound.
    zwsdotcom, Nov 21, 2006
  15. Alf Katz

    BillW50 Guest

    Oh okay, I stand corrected! Thanks zwsdotcom ;)
    BillW50, Nov 21, 2006

  16. Commodore released manuals with schematics for their 8088 and 80286
    IBM clones. I had originals of each, about 10 years ago.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
    Michael A. Terrell, Dec 15, 2006
  17. Alf Katz

    Ben Myers Guest

    Actually, now that you mention it, I think that IBM's reference manuals for the
    PC XT and/or the PC/AT may have had some crude circuit diagrams. But those were
    a long time ago, back when circuit boards were single layer... Ben Myers
    Ben Myers, Dec 16, 2006
  18. Alf Katz

    BillW50 Guest

    message [...]
    I don't know why I didn't think of this before, as I have used the FCC
    website before. But supposedly anything with a FCC number, had to file a
    schematic with the registration. I never thought about computers, but I
    have gotten schematics for other devices before. Might be worth a shot.



    The second one takes you to the search page, I hope. <grin>
    BillW50, Dec 21, 2006
  19. Alf Katz

    JHEM Guest

    No longer true, one need only file a block diagram describing process flow
    and voltages. MB schematics for computers have been deemed proprietary.
    JHEM, Dec 21, 2006
  20. Alf Katz

    zwsdotcom Guest

    Not strictly true. The full information is still in the filing. Certain
    information can be kept off the public record as a trade secret
    (exactly what you can get classified this way depends on how well your
    lawyer can dance).
    zwsdotcom, Dec 21, 2006
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.