Spectrum 16k - Sinclair

This is a discussion on Spectrum 16k - Sinclair ; I just picked up one of these from a car boot sale, boxed (battered box though) Unfortunately it's borked, and I get flashing squares etc on bootup. Occasionally it gets to the copyright message and I can press a few ...

+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 20 of 28

Thread: Spectrum 16k

  1. Spectrum 16k

    I just picked up one of these from a car boot sale, boxed (battered box
    though)

    Unfortunately it's borked, and I get flashing squares etc on bootup.
    Occasionally it gets to the copyright message and I can press a few keys,
    then it goes wrong again.

    Dodgy ULA? Could it be fixed? It's an issue 2.

    Thanks
    Pokey.



  2. Re: Spectrum 16k

    Pokey did eloquently scribble:
    > I just picked up one of these from a car boot sale, boxed (battered box
    > though)


    OI!
    Pokey, getcher arse back in #speccy, you ingrate.


    > Unfortunately it's borked, and I get flashing squares etc on bootup.
    > Occasionally it gets to the copyright message and I can press a few keys,
    > then it goes wrong again.


    > Dodgy ULA? Could it be fixed? It's an issue 2.


    Something's overheating by the sound of it...
    If it was a totalled ULA, would you ever get the copyright message?
    Think the only way to fix it would be to find a machine with something else
    broken and swap parts, these days.
    --
    __________________________________________________ ____________________________
    | spike1@freenet.co.uk | "Are you pondering what I'm pondering Pinky?" |
    |Andrew Halliwell BSc(hons)| |
    | in | "I think so brain, but this time, you control |
    | Computer Science | the Encounter suit, and I'll do the voice..." |
    ------------------------------------------------------------------------------

  3. Re: Spectrum 16k


    wrote in message
    news:le1bj4-d38.ln1@ridcully.ntlworld.com...
    > Pokey did eloquently scribble:
    >> I just picked up one of these from a car boot sale, boxed (battered box
    >> though)

    >
    > OI!
    > Pokey, getcher arse back in #speccy, you ingrate.
    >
    >
    >> Unfortunately it's borked, and I get flashing squares etc on bootup.
    >> Occasionally it gets to the copyright message and I can press a few keys,
    >> then it goes wrong again.

    >
    >> Dodgy ULA? Could it be fixed? It's an issue 2.

    >
    > Something's overheating by the sound of it...
    > If it was a totalled ULA, would you ever get the copyright message?
    > Think the only way to fix it would be to find a machine with something
    > else
    > broken and swap parts, these days.
    > --
    >


    My guess would be a dicky memory chip. open it up and see which chip if any
    gets hot really quickly. If its not the memory chips themselves it might be
    the supply circuits, funny transistorised inverter thing that i never did
    fully understand.

    Andy
    __________________________________________________ ____________________________
    > | spike1@freenet.co.uk | "Are you pondering what I'm pondering Pinky?"
    > |
    > |Andrew Halliwell BSc(hons)|
    > |
    > | in | "I think so brain, but this time, you control
    > |
    > | Computer Science | the Encounter suit, and I'll do the
    > voice..." |
    > ------------------------------------------------------------------------------



  4. Re: Spectrum 16k

    > My guess would be a dicky memory chip. open it up and see which chip if
    > any gets hot really quickly. If its not the memory chips themselves it
    > might be the supply circuits, funny transistorised inverter thing that i
    > never did fully understand.
    >
    > Andy


    I had it running for a while - the memory chips are all cool but the ULA is
    too hot to touch.
    I have a Plus 2 somewhere, can I use the ULA from that? (assuming it is
    socketed of course)



  5. Re: Spectrum 16k

    Pokey wrote:
    >> My guess would be a dicky memory chip. open it up and see which chip if
    >> any gets hot really quickly. If its not the memory chips themselves it
    >> might be the supply circuits, funny transistorised inverter thing that i
    >> never did fully understand.
    >>
    >> Andy

    >
    > I had it running for a while - the memory chips are all cool but the ULA is
    > too hot to touch.
    > I have a Plus 2 somewhere, can I use the ULA from that? (assuming it is
    > socketed of course)
    >
    >

    Nope. Issue 2 machines ULA is a ULA5C112E. Later models of ULA are quite
    different, so an original issue 2 machine is the ONLY model from where a
    replacement can be sourced. Plus 2 ULA is entirely different. ULA
    normally gets a wee bit hot when powered up. Memory chips will only
    become hot if faulty. Could be the power regulation circuits, perhaps.

  6. Re: Spectrum 16k


    "chroma" napísal v správe
    news:46633005$0$31839$db0fefd9@news.zen.co.uk...
    > Pokey wrote:
    >>> My guess would be a dicky memory chip. open it up and see which chip if
    >>> any gets hot really quickly. If its not the memory chips themselves it
    >>> might be the supply circuits, funny transistorised inverter thing that i
    >>> never did fully understand.
    >>>
    >>> Andy

    >>
    >> I had it running for a while - the memory chips are all cool but the ULA
    >> is too hot to touch.
    >> I have a Plus 2 somewhere, can I use the ULA from that? (assuming it is
    >> socketed of course)
    >>
    >>

    > Nope. Issue 2 machines ULA is a ULA5C112E. Later models of ULA are quite
    > different, so an original issue 2 machine is the ONLY model from where a
    > replacement can be sourced. Plus 2 ULA is entirely different. ULA normally
    > gets a wee bit hot when powered up. Memory chips will only become hot if
    > faulty. Could be the power regulation circuits, perhaps.


    After all this conversation I assume it could be a cold circuit on the
    motherboard (I don't know how to tell it in English we call it cold circuit
    it's a junction on motherboard circuit that sometimes is good and sometimes
    fault, it couldn't sometimes flow the electricity) I hope you understand
    what I wanted to say. This happens on old Spectrum motherboards, I remember
    that I turned on my Spectrum48k+ and when touched a bit harder the case, it
    behaved right the same as you describe.

    B


  7. Re: Spectrum 16k

    On 2007-06-04, Bohus Král wrote:

    > After all this conversation I assume it could be a cold circuit on the
    > motherboard (I don't know how to tell it in English we call it cold circuit
    > it's a junction on motherboard circuit that sometimes is good and sometimes
    > fault, it couldn't sometimes flow the electricity)


    That's known as a "dry joint", which can cause intermittent faults, as
    opposed to a "big fat joint" which can make most things seem intermittent.

    To get rid of a dry joint, a dab of heat from a soldering iron often
    does it, if not then some solder in addition will usually do it.
    Finding it can be hard, usually involves pressing and wiggling
    components while the unit is powered up.

    --
    Blast off and strike the evil Bydo empire!

  8. Re: Spectrum 16k


    "Ian Rawlings" napísal

    > To get rid of a dry joint, a dab of heat from a soldering iron often
    > does it, if not then some solder in addition will usually do it.
    > Finding it can be hard, usually involves pressing and wiggling
    > components while the unit is powered up.


    I think it's practically unrepairable, because there can be thousands of dry
    joints on old mainboard.

    B


  9. Re: Spectrum 16k

    On 2007-06-04, Bohus Král wrote:

    > I think it's practically unrepairable, because there can be thousands of dry
    > joints on old mainboard.


    Generally not many dry joints, but it can be hard to repair an old
    computer if you don't know anything about it. I did a short stint in
    a computer repair shop back when spectrums were still around (plus
    three was the current model) and one chap there didn't understand how
    to fix them but just kept swapping components until it worked. It's
    not practical to do that any more as the components aren't that easy
    to come by and the spectrum-specific replacements you can get may well
    be dead as well as they'll be off a similarly ancient computer.

    --
    Blast off and strike the evil Bydo empire!

  10. Re: Spectrum 16k

    Sounds like dodgy ram to me, or the -5v supply from what was it? tr4 or 5
    could never remember. However, I'd plump for an overheating ram chip

    That is not to say it has not got other issues of corse, like no colour on
    most tv's for instance. :-)

    Brian

    --
    Brian Gaff - briang1@blueyonder.co.uk
    Note:- In order to reduce spam, any email without 'Brian Gaff'
    in the display name may be lost.
    Blind user, so no pictures please!
    "Pokey" wrote in message
    news:n4A8i.6481$J15.3793@newsfe3-gui.ntli.net...
    >I just picked up one of these from a car boot sale, boxed (battered box
    >though)
    >
    > Unfortunately it's borked, and I get flashing squares etc on bootup.
    > Occasionally it gets to the copyright message and I can press a few keys,
    > then it goes wrong again.
    >
    > Dodgy ULA? Could it be fixed? It's an issue 2.
    >
    > Thanks
    > Pokey.
    >
    >




  11. Re: Spectrum 16k

    Bohus Král did eloquently scribble:

    > "chroma" napísal v správe
    > news:46633005$0$31839$db0fefd9@news.zen.co.uk...
    >> Pokey wrote:
    >>>> My guess would be a dicky memory chip. open it up and see which chip if
    >>>> any gets hot really quickly. If its not the memory chips themselves it
    >>>> might be the supply circuits, funny transistorised inverter thing that i
    >>>> never did fully understand.
    >>>>
    >>>> Andy
    >>>
    >>> I had it running for a while - the memory chips are all cool but the ULA
    >>> is too hot to touch.
    >>> I have a Plus 2 somewhere, can I use the ULA from that? (assuming it is
    >>> socketed of course)
    >>>
    >>>

    >> Nope. Issue 2 machines ULA is a ULA5C112E. Later models of ULA are quite
    >> different, so an original issue 2 machine is the ONLY model from where a
    >> replacement can be sourced. Plus 2 ULA is entirely different. ULA normally
    >> gets a wee bit hot when powered up. Memory chips will only become hot if
    >> faulty. Could be the power regulation circuits, perhaps.


    > After all this conversation I assume it could be a cold circuit on the
    > motherboard (I don't know how to tell it in English we call it cold circuit
    > it's a junction on motherboard circuit that sometimes is good and sometimes
    > fault, it couldn't sometimes flow the electricity)


    Dry joint. (bad solder/soldering)
    Unlikely. There are a few faults, some, like dry joints are intermittent
    connections. Possibly even triggering a reset by shaking the machine.
    It's possible to run for quite a while with a dry joint. His problem seems
    to always happen before he can type anything.

    If a machine sometimes works for a while and then goes kablooeee, and
    sometimes doesn't work at all from the get go...It's usually a heating
    problem.(any number of components can overheat like this, as suggested in
    this thread, could be RAM, ROM, the CPU itself, the ULA or even the power
    regulator)

    From cold, powering up, accessing the rom, running the self test... getting
    a little warm, printing the copyright message... going into the user input
    cycle and.... hothothothotOOO,nasty crash.

    From warm it might go straight to "Oooo nasty crash"

    --
    -----------------------------------------------------------------------------
    | spike1@freenet.co.uk | Windows95 (noun): 32 bit extensions and a |
    | | graphical shell for a 16 bit patch to an 8 bit |
    |Andrew Halliwell BSc(hons)| operating system originally coded for a 4 bit |
    | in |microprocessor, written by a 2 bit company, that|
    | Computer Science | can't stand 1 bit of competition. |
    -----------------------------------------------------------------------------

  12. Re: Spectrum 16k


    napísal

    > His problem seems
    > to always happen before he can type anything.


    It doesn't mean that it cannot be a dry joint. If he has dozens of dry
    joints, the machine would behave exactly as he describes.

    The dry joints can appear by unsafe carrying the machine for years.

    B


  13. Re: Spectrum 16k

    On 2007-06-04, Bohus Král wrote:

    > It doesn't mean that it cannot be a dry joint. If he has dozens of dry
    > joints, the machine would behave exactly as he describes.


    I wouldn't get too hung up on this dry joint thing B, it could be any
    number of things, and dozens of dry joints is not that likely. You
    can get a few on chips in chip holders and the first thing to do is to
    press down on any chips that aren't soldered directly to the board,
    that sometimes clears things up.

    --
    Blast off and strike the evil Bydo empire!

  14. Re: Spectrum 16k


    "Ian Rawlings" napísal
    > ....and dozens of dry joints is not that likely. You
    > can get a few on chips in chip holders and the first thing to do is to
    > press down on any chips that aren't soldered directly to the board,
    > that sometimes clears things up.


    Yes, but on old mainboard the dry joints do not have to appear just on chips
    and sockets, but also on the flat circuit itself (I don't know how to tell
    this in English again, we call mainboard or similar boards the flat
    circuits) . The dry joints may be on the surface of flat circuit which is
    very sensoble for mechanical handling and on the flat circuit from 1982 it
    is very liable.

    B


  15. Re: Spectrum 16k

    Bohus Král wrote:

    ....
    > Yes, but on old mainboard the dry joints do not have to appear just on
    > chips and sockets, but also on the flat circuit itself (I don't know how
    > to tell this in English again, we call mainboard or similar boards the
    > flat circuits) .


    I think that's the PCB - Printed Circuit Board: it's made up of Tracks that
    run between Components; they can be single sided, double sided, single
    layer, multi-layered, etc. The components on older boards are usually
    soldered onto circular pads in the tracks (with leads pushed through from
    one side {where the compents are} to the other {usually with the majority of
    the tracks}).


  16. Re: Spectrum 16k

    On 2007-06-04, Bohus Král wrote:

    > Yes, but on old mainboard the dry joints do not have to appear just on chips
    > and sockets, but also on the flat circuit itself


    Yes I know the places they can appear, but "dozens" of dry joints on
    an actual circuit board isn't common, not totally out of the question,
    but not likely to be "dozens" on a circuit board.

    You can blame world famine on dry joints if you want but I think
    you're placing too much faith in them..

    --
    Blast off and strike the evil Bydo empire!

  17. Re: Spectrum 16k

    anon wrote:

    > funny transistorised inverter thing that i never did
    > fully understand.


    All the best Speccy experts post to CSS.

    --
    Duncan Snowden.

  18. Re: Spectrum 16k


    "Ian Rawlings" napísal

    > You can blame world famine on dry joints if you want but I think
    > you're placing too much faith in them..


    I am speaking by my own experience with my Spectrum48k+ which after 20 years
    of usage had totally damaged mainboard.

    B


  19. Re: Spectrum 16k

    On Mon, 4 Jun 2007 Bohus Král wrote:

    >I think it's practically unrepairable, because there can be thousands
    >of dry joints on old mainboard.


    If the board has all, or at least the vast majority, of its components
    on one side it's sometimes possible to resurrect a multi-dry-joint
    circuit board by turning it upside down onto some dissipative foam and
    GENTLY playing a heat gun across the non-component side. It's like a
    poor man's solder bath.

    There are many things that can go wrong doing this. You can burn the
    PCB, you can lift thin tracks clean off the board, you can overheat
    components to the point of permanent death, you can melt the plastic
    formers of coils or chip sockets, and you can set fire to the foam. And
    if your components have a large range of physical sizes or you don't
    press down enough on the foam, all the smaller components can drop right
    out of the PCB as you heat up their legs and you'll never figure out
    where they went! It's definitely an art rather than a science.

    On the other hand if the board is pretty much goosed anyway, you have
    little to lose. I've resurrected a few old transistor radios, cassette
    players and the like using this method. Normally ones that have been
    left out in a garden shed or garage for a year or two and have expanded
    and contracted themselves to death.

    I've never tried it with a Speccy, mind.

    --
    Kev
    __________________________________________________ ________________________
    "If you don't believe you can win, there is no point in getting out of bed
    at the end of the day." Neville Southall

  20. Re: Spectrum 16k

    On Mon, 4 Jun 2007 20:07:12 +0100 da kidz on comp.sys.sinclair were rappin'
    to MC Kevin Reilly:

    > "If you don't believe you can win, there is no point in getting out of bed
    > at the end of the day." Neville Southall


    Why would you be getting out of bed at the end of the day? That's the
    time you should be getting into bed, shirley?

    Chris


    --
    +-------------------------------------------+
    | Unsatisfactory Software - "because it is" |
    | http://www.unsatisfactorysoftware.co.uk |
    | Your Sinclair: A Celebration |
    +- http://www.yoursinclair.co.uk -----------+

    DISCLAIMER: I may be making all this stuff up again.

+ Reply to Thread
Page 1 of 2 1 2 LastLast