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Speccy dead? :-(

hldswrthhldswrth
edited December 2006 in Hardware
I've been playing around with my Speccy and a Discovery disc drive unit, and tried to do the NMI modification to allow a multiface to be plugged into the side port - my desk is just not deep enough to accommodate the Speccy with Discovery and multiface in between.

Well, I connected the NMI line (I believe, top of the connector 9 lines in from the notch) from the Opus's Speccy connector to the corresponding line on the Opus's expansion connector, plugged in the Multiface and Speecy, powered on, but when I pressed the button on the Multiface, I got coloured vertical lines on the screen.

At this point the Spectrum and Opus were working fine. I'd used the multiface in the last few days, so assumed that should be working too.

I then tried the Multiface in between the Speccy and the Opus. This time I got the vertical lines too, however now when I reset the Speccy I get a cyan border, with thick alternating black and white vertical lines :-(

I've left the Speccy off for a while and powered it up on its own, and now all I ever get is the same - cyan border with vertical black and white lines.

So, the question is, just how dead is the Speccy? I'm really hoping I've not caused any damage to the Opus unit as they are much harder to find...

I'm surprised that just connecting the NMI line like that could result in damage to the Speccy. I'm sure I didn't connect or disconnect anything with power on...

Any ideas?

Cheers, Simon
Post edited by hldswrth on

Comments

  • hldswrthhldswrth
    edited December 2006
    Aaaarrggghhh!

    I tried a different Spectrum with the Opus (after removing the connection I made earlier), and now I have TWO dead Speccies, and I'm pretty sure the Opus is dead too.

    How the hell all that can happen from connecting the NMI line is beyond me 8-(

    Very Sad, Simon
  • LloydLloyd
    edited December 2006
    How dead? Unable to tell without having the Speccies in front of me to test. Possible problems include ROM/RAM/Z80?ULA. Assuming you want them fixed, you can either PM Spirantho or DEATH, or maybe if you know what you're doing, fix them yourself.

    First, look at the edge connector of the Opus and Multiface. Is the key still in place? If you don't know what I mean, on the edge connector should be a little plastic keyway that slots into the slot on the motherboard. If this is missing, it'll cause mis-alignment problems and just the problems you've described.

    Sorry mate, can't help any more unless I see them.
  • WinstonWinston
    edited December 2006
    hldswrth wrote:
    How the hell all that can happen from connecting the NMI line is beyond me 8-(

    Very Sad, Simon

    I learned at an early age not to touch the Speccy's edge connector. I managed to kill mine twice that way, just trying to add a very simple circuit (I don't remember what it was supposed to do now, I just remember having to explain to my parents why the Speccy was dead AGAIN).

    It seems like the ULA is extremely fragile, and will die if you just look at it the wrong way. I think the Z80 is a bit more robust (after all, I have a Z80 on some breadboard that I've been abusing for a good week, and it still works).
  • DEATHDEATH
    edited December 2006
    Winston wrote:
    I learned at an early age not to touch the Speccy's edge connector. I managed to kill mine twice that way, just trying to add a very simple circuit (I don't remember what it was supposed to do now, I just remember having to explain to my parents why the Speccy was dead AGAIN).

    It seems like the ULA is extremely fragile, and will die if you just look at it the wrong way. I think the Z80 is a bit more robust (after all, I have a Z80 on some breadboard that I've been abusing for a good week, and it still works).

    Due to the fact that there's no buffering on the data lines, the Z80 is very prone to getting fried. It may be a moe hardy chip, but I've binned far more of them than I have ULA chips. The 4116/4164 RAM and the ROM are also quite likely to go pop if the edge connector is shorted out too.
    Oh bugger!<br>
  • WinstonWinston
    edited December 2006
    DEATH wrote:
    <snip> The 4116/4164 RAM and the ROM are also quite likely to go pop if the edge connector is shorted out too.

    I think if I ever pluck up the courage to mess with my only working Speccy's edge connector again, whatever experimental circuit I connect will be behind a 74HCT125 or similar! But knowing my luck, I'll still manage to do something wrong on the sensitive side of the buffer :/
  • hldswrthhldswrth
    edited December 2006
    So I'm pretty sure the problem is that on the Discovery, even when the unit is switched off at the back, there are live lines on the connector, so if you disconnect the computer with the unit plugged into the mains, there's a chance of crossing tracks and blowing something.

    That might be why they stuck a big sticker on the Discovery telling you to unplug it before attaching/detaching the Spectrum. If I'd read that I wouldn't have fried three boards :-(

    So anyone reading this with a Discovery - PULL THE PLUG before you disconnect the Spectrum!

    Cheers, Simon
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