Sinclair ZX Spectrum 128

edited February 2015 in Sinclair Miscellaneous
My loving mum has brought me back one of these beauties from a carboot sale but I'm haven a slight problem with it

I CAN'T FIND THE ON SWITCH!!!!!!!!!!

All the manual says is "this is the screen you will see when you turn it on or use the reset button at the side"

Any one know how to turn the s.o.b on???
Post edited by Null n Void on
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Comments

  • edited July 2003
    Just plug in the power supply and then it should turn on.

    Pull the plug out to switch it off :)

    You might have a problem tuning it in if you are using a modern TV.
  • edited July 2003
    Cheers mate altho dont lock this topic yet please :)

    I am usin a modern tv any ideas on how to tune it into it? or any alterintave?

    I'm goin to try it on an older tv altho I aint sure exactly how achient it is
  • edited July 2003
    It tunes in on channel 36 or threabouts, isn't that right? It's roughly in the same place on the dial as your VCR picture is unless I'm mistaken.
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  • edited July 2003
    Hmm not sure if your usin american tvs or somethin but I aint got a "channel" to tune things into here you can tune anything into any channel

    But it should be around where me video tunes in cool

    another question is there any signs of it accualy being on?
  • edited July 2003
    On 2003-07-19 00:45, Null n Void wrote:
    Hmm not sure if your usin american tvs or somethin but I aint got a "channel" to tune things into here you can tune anything into any channel

    But it should be around where me video tunes in cool

    another question is there any signs of it accualy being on?
    it'll probably buzz quietly a bit and get warm.
    Speccys will work with older TVS, but they don't like modern digital tuners, so if it is working you'll get a picture, but the signal may wander and you'll probalby have to re-tune it every so often. It depends on the type of TV really but I use several real speccys on a modern tv and it works reasonably well.
  • edited July 2003
    Hmm no hummin coming from it and i've had it plugged in all night and it's not any warmer I think it's busted, damn altho I might just be the power pack I think my mates got one I'll see if I can get that from him

    Cheers for yer help
  • edited July 2003
    On 2003-07-19 00:45, Null n Void wrote:
    another question is there any signs of it accualy being on?
    If it's an original 128K model (I'm not sure about the Amstrad +2, +2A and +3) you can test the beeper. Swith the machine on, hold the <BREAK> key and press the reset button on the left hand side. This invokes a test screen.
    If you hear nothing, I'm afraid it's broken...
  • edited July 2003
    If your`re getting no picture but want to test that it`s working then plug some walkman headphones into the ear/mic socket and press the keys. You should hear a short click every time a key is pressed.

    If there is no clicks when the keys are pressed then either the Spectrum or the powerpack (or both) have died.

    Mat
  • edited July 2003
    Right, quick solution. (possibly) :)

    It can be a pain in the neck messing around with old kit and modern tellies.

    Plug the RF-Lead into the back of your VCR where it says TV-IN (or RF-IN or similar)
    then if you have a SCART out on your video, it should auto tune.

    Or, if you have RF-OUT you can just re-tune a channel on the video, in the same way you would any other tv channel.
  • edited April 2014
    Hey folks thanks for the replies. The Speccy is packed away just now whilst we prepare to move house but I'm planning on looking into it again soon. Might even pull it out before we move just to see if I can get it going.

    (P.S. sorry for the delay in replying, I was busy)
  • edited April 2014
    11 years for replying, yep, I guess you might have been very busy ! :D
    Take care of your 128k while moving !!! ;-)
    Super Spectrum 128k+4 : +2A case, +2 motherboard, internal divIDE + SD
    Spectrum 48k+ / 128k+ / 128k+2 / +2A (2) / +3 with Multiface3
    SpeccyPi 128k+3,14...
    Yes, I only love the + versions !!!
  • edited April 2014
    Probably went out for bread and milk and got lost on the way home, lol
    So far, so meh :)
  • edited April 2014
    polomint wrote: »
    Probably went out for bread and milk and got lost on the way home, lol

    Maybe he met the girl of his life when looking for the way back home, got a dozen kids and raised them, started some company and retired, built a house at a lake and moving over there now.

    He deserves a medal for perseverence!
  • edited April 2014
    polomint wrote: »
    Probably went out for bread and milk and got lost on the way home, lol

    Or tried to finish 'Mr Wimpy'
  • edited April 2014
    Best Necrobump ever.
  • edited April 2014
    bverstee wrote: »
    Maybe he met the girl of his life when looking for the way back home, got a dozen kids and raised them, started some company and retired, built a house at a lake and moving over there now.

    He deserves a medal for perseverence!

    Not far off with that description actually, met the girl, married her, only 1 kid so far, worked at a start up company, bought a house, now bought a new one near a loch and moving there now. Squeezed in a degree in A.I. as well.

    More importantly though I installed a spell checker into my browser and learnt how to talk online, my other posts are atrocious.
    chop983 wrote:
    Best Necrobump ever.

    Glad you like it, genuine as well, would be great to say we actually got the Speccy fixed after 11 years.
  • edited April 2014
    would be great to say we actually got the Speccy fixed after 11 years.

    Absolutely :) Just don't go buggering off again until 2025 :grin:

    B
    The Spectrum Resuscitation Thread - bringing dead Spectrums back to life
    zx-diagnostics - Fixing ZX Spectrums in the 21st Century (wiki)
    Sinclair FAQ Wiki
  • edited April 2014
    balford wrote: »
    Absolutely :) Just don't go buggering off again until 2025 :grin:

    B

    Hahahah, indeed: welcome back!
  • edited April 2014
    What's great about this thread is most of the people who replied in 2003 are still here :)

    You can check out any time you like, etc
    The comp.sys.sinclair crap games competition 2015
    "Let's not be childish. Let's play Spectrum games."
  • zx1zx1
    edited May 2014
    leespoons wrote: »
    What's great about this thread is most of the people who replied in 2003 are still here :)

    Which shows you how old we are all getting:sad:
    The trouble with tribbles is.......
  • edited May 2014
    zx1 wrote: »
    Which shows you how old we are all getting:sad:

    On the contrary, it shows that we still haven't grown up. ;)
  • edited May 2014
    Well, the suspense is killing me! Did the 128k work or not?
  • edited May 2014
    Arjun wrote: »
    Well, the suspense is killing me! Did the 128k work or not?

    He didn't test it yet, but he mentioned he's planning on looking into it again soon... probably right after his kid graduates from college!
    Creator of ZXDB, BIFROST/NIRVANA, ZX7/RCS, etc. I don't frequent this forum anymore, please look for me elsewhere.
  • edited May 2014
    He didn't test it yet, but he mentioned he's planning on looking into it again soon... probably right after his kid graduates from college!

    Hopefully not quite that long but yes it is still on hold due to house matters.

    In the meantime I've been looking into possible causes for it not working and watching the array of videos on YouTube. Most are about the 48k though but I'm sure many of the principles are the same.

    If anyone has any resources they think would be of particular use then please do share.
  • edited November 2014
    Hey guys, it's the moment we've all been waiting for.

    I've taken a week off work and I plan on getting this system up and running before I go back.

    Here are the systems I have:


    6b568c11-caf3-44be-9435-aebc8b5a671d_zps128cb011.jpg


    to the left is the working ZX Spectrum +2 and to the right is the non-working ZX Spectrum +. I'm hoping I can compare systems to help me work out the issue but I'll need to find out how similar they are internally.

    I see no-one has replied to my last call for help, that's understandable. I don't plan on just posting asking for help, I'm going to see this through this week and will post along with my progress as I do so that it may help someone else repair their system.

    One clear flag for an issue is this strange resin on the power cable:


    a0aacb6e-fc79-4264-b231-b7009bfa9820_zps4e342643.jpg


    It has a really strange smell as well, could just be age but I think it has a similar smell to old batteries so perhaps some sort of fault with the power supply itself. I'm going to search through my parts for a spare power adapter and see if that is enough to get it going. I'll also try testing this one with a voltmeter and see if I can register anything.

    Will let you know how I get on.
  • edited November 2014
    One clear flag for an issue is this strange resin on the power cable:


    a0aacb6e-fc79-4264-b231-b7009bfa9820_zps4e342643.jpg


    It has a really strange smell as well, could just be age but I think it has a similar smell to old batteries so perhaps some sort of fault with the power supply itself. I'm going to search through my parts for a spare power adapter and see if that is enough to get it going. I'll also try testing this one with a voltmeter and see if I can register anything.

    Will let you know how I get on.

    The resin is from the styrofoam the power supply was in.
    It's hard to clean it: it seems the rubber of the cable and styrofoam 'melt' together after 30 years, probably due to their chemical composition.
    But nothing to worry about: the rubber does not tear apart because of this, at least I never had that (had dozens of supplies in my hand).
  • edited November 2014
    bverstee wrote: »
    The resin is from the styrofoam the power supply was in.
    It's hard to clean it: it seems the rubber of the cable and styrofoam 'melt' together after 30 years, probably due to their chemical composition.
    But nothing to worry about: the rubber does not tear apart because of this, at least I never had that (had dozens of supplies in my hand).

    Good to know bverstee, I'll most likely wrap the cable in a sandwich bag before storing from now on.

    A bit more progress tonight.

    I checked the supply with my voltmeter and it is reading fine. The Spectrum also reads a voltage just on the other side of the connector when plugged in:

    509624b3-8622-48c5-893e-b376e0356d68_zpsc5d517f6.jpg

    So that's a good sign because although I have 2 other adjustable power supplies I have lost the connectors for both, great.

    Moving on, since the power isn't the issue it must be the system. Opening it up presents us with the following:

    a3d74039-252d-4ea9-aa25-43afde489977_zps64b5e39c.jpg

    The inside of a Spectrum, who'd have thought it!

    I remember from a while back I attempted the repair. If I recall correctly I based it purely on looks so I may have soldered in a completely inappropriate part so that's where I'm going to start looking.

    You may have already seen it in the previous pics on the right but here it is close up:

    482c479c-a2ac-494c-afee-6a471a1bf1b1_zps3419e952.jpg

    99d1f17d-478a-4aa1-87c7-db218037fb95_zps97c88199.jpg

    I'm not even sure what the part is, I think there are a couple of components that look similar to this. What I do know is it heaps up a lot and fast when plugged in. I'm really surprised at how good my soldering was back then, better than it is now!

    Next up is watching and reading more about what this part is actually meant to be and getting it replaced. Any advice to expedite things would be greatly recieved.
  • edited November 2014
    That part is (or should be) a 78S05 voltage regulator. The wiring looks ok (red to right hand pin, blue to left, centre to ground).

    It does need to be screwed to the metal heatsink though, preferably with a smear of heatsink compound between both surfaces.

    This is because its job is to convert the unregulated voltage (somewhere between 10-12v) from the power brick into a nice stable 5v supply for the board. This process generates a lot of heat, hence the heatsink!

    When the machine's plugged in, check the voltages on the left and right pins with a multimeter, with the ground probe on centre (be careful not to short it!)

    You should be seeing 5v or near enough on the rightmost pin.

    B
    The Spectrum Resuscitation Thread - bringing dead Spectrums back to life
    zx-diagnostics - Fixing ZX Spectrums in the 21st Century (wiki)
    Sinclair FAQ Wiki
  • edited November 2014
    balford wrote: »
    That part is (or should be) a 78S05 voltage regulator. The wiring looks ok (red to right hand pin, blue to left, centre to ground).

    ...

    You should be seeing 5v or near enough on the rightmost pin.

    B

    That's the voltage I'm getting, around 11v on the left, 5v on the right. Quite glad I solder this in the right way round as I think it was a bit of a 50/50 shot at the time.

    I think my soldering also isn't quite as good as I first assumed. I thought I had soldered the wires in place but when I look closer I think they were always there and I just soldered the regulator to them. That's why there are lots of loose strands on the reg pins. I'll get them fixed up and keep looking.

    I'm going to run through the tests for the 48K explained in this video: https://www.youtube.com/watch?v=IzgCmldm2H4

    Would I be right in thinking many of them still apply to the 128K+ ? (It is surprisingly hard to find information specific to the + and not the +2.)
  • edited November 2014
    Just to help with your tuning problems. You have a +2 there. Does it tune-in fine on the TV your using? If it does the +128 will use the same channel as your +2 as all computers/consoles I've known all output the RF on channel 36 here in the UK(roughly UHF 590 Mhz). Channel 5 use to broadcast also on channels 35, and 37 - try the channel preset you used to receive the Channel 5 TV station on, it would show at least a not quite tuned-in-fuzzy picture. Also have you tryed swapping the RF cables between the 2 Speccy's you have? You might have a dodgy RF cable.

    If the above still don't work I would invest in a RGB to SCART cable. This would end your tuning issue's and if the Speccy is working fine, it will give a far better picture than the old RF output. I would try that before trying to find further faults as you could easily cause further expensive problems if you can't see the what the Speccy is doing. It may just be a faulty TV modulator, but you won't need that with a RGB to SCART cable.
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