Getting a +3 working again (keyboard & tape socket issues)

So, as part of my Spectrum restoration project I will also try to tackle the problem child among my fleet, the +3.

PROBLEM ONE:
Ever since I first tested this computer I've known there were some keys that weren't working, I just couldn't remember which ones. I can now confirm the keys are:
3, 8, E, I, D, X, K, M.
However, I was also testing some Sinclair joysticks and found that even though they were all working perfectly on the +2, +2A and +2B, none of them register "down" on the +3 - which is 8 on port 1 and 3 on port 2.
It seemed somewhat odd that the eight keys that weren't working were all arranged in columns. So I thought of that program in the +2/+3 manual that demonstrates the IN function (three lines, chapter 23) and how pressing keys on a particular half-row of five keys changes the value of IN ***** (whichever address is being read) from 191 to... something else. I tried this program on the +2B, which I know is working completely fine and would be the closest match to the +3. Imagine my complete lack of surprise when all the values of the +3's non-functioning keys were 187.
The right arrow key works, as do the full stop and TRUE VIDEO keys which are all Caps Shift plus a non-working key.
Because the joysticks aren't giving 3 and 8 values either, this suggests it's not a problem with the physical keyboard, rather some complicated internal bit that's reading and interpreting the keypresses.

PROBLEM TWO:
I have no discs so I can't test the disc drive (though it whirrs on startup in a way that suggests it's fine - I never owned a +3 back in the day so I have no memories to compare with). But with the J and " keys working I thought I could at least try to load from tape in 48K mode (because I can't type LOAD "t:" in +3 BASIC due to the non-working D key). I found a working monaural tape deck - my grandad's Philips Magic Cube (tape, FM/MW/LW radio and black-and-white TV all in one!) that he kept in his caravan. The door is falling off and I don't think the heads had been cleaned since he was alive (which he wasn't by the end of 1991) but after another wash and brush up with some 99% isopropanol the way I've done with three +2/+2A/+2B Datacorders it's running well. The deck plays music, the EAR socket works (even if it only sends music to the left channel) and I found the part in the +3 manual that specifies what lead to use - a standard stereo 3.5mm jack on one end for the TAPE/SOUND socket on the +3, two mono 3.5mm jacks on the other for the EAR and MIC sockets on the tape deck. I didn't have that but I do have a 3.5mm stereo jack to red-and-white RCA plugs along with a couple of RCA-to-mono 3.5mm jack adapters. Whichever plug I put into the EAR socket, red or white, I was treated only to the sound of an unoiled chainsaw trying to hack through concrete. So I tried it in the +2B - and again it didn't matter whether I plugged the red or white lead into the TAPE/SOUND socket, I did at least get proper sound coming through into the TV speaker, whether it was Iron Maiden or the loading tones of Alien Destroyer (which I have four copies of and didn't mind if one gets chewed up in the Magic Cube). It seems that even though the +2B is nothing more than a +3 with a tape deck, the TAPE/SOUND socket on that is pretty much cosmetic as it won't interpret any sound coming into it as a valid call to load, whereas on the +3 that's its primary function. And on the +3, of all the machines that it could happen to, this socket is ruined.
I will take note of Your Spec-chum's recommendation on my other thread of Servisol contact cleaner and give it a blast with that, in case it is just filthy contacts that aren't working properly, but I will assume nothing at this stage.

PROBLEM THREE:
When investigating the keyboard issues, before trying the IN function program I opened the case just to see what it looks like inside. There's a screw missing that holds the disc drive down... and is this wire supposed to be connected to something? The screw it's supposedly being held down by won't go any further into the plastic peg and it's loose, which I'd assume it shouldn't be.

+3innards.jpg

Comments

  • Try giving the tails of the keyboard membrane a clean with a very light abrasive, such as a "blue" rubber or even just a bit of kitchen paper towel.

    The wire with one end free should be connected to ground. It's normally put under one of the screws that goes through a silver pad in the PCB, just above where you have labelled the loose screw. It's likely that screw is loose because someone has incorrectly put a slightly longer one in. The missing screw often seems to be missing and will cause no harm
  • edited February 2017
    1> The Amstrad 40077 gate array chip does the decoding/encoding of the keyboard and joystick inputs... Schematics for the ZX Spectrum +2A/+3, +2B, and +3B here. Keyboard matrix here. I can only suggest you test the PCB tracks (traces) between the connectors (keyboard "KBY3", joystick pin 9,) and the pin of the gate array chip (pin 30) plus the associated resistor (R11).

    2> The Tape/Sound jack socket on any +2 is only wired for sound out. Unless the computer is modified, it is not possible to use an external tape deck to load programs and games using this connector.

    Mark
    Post edited by 1024MAK on
    Sinclair FAQ Wiki
    Repair Guides. Spanish Hardware site.
    WoS - can't download? Info here...
    former Meulie Spectrum Archive but no longer available :-(
    Spectranet: the TNFS directory thread

    ! Standby alert !
    “There are four lights!”
    Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
    Looking forward to summer in Somerset later in the year :)
  • edited February 2017
    I should probably point out that not once in my 33 years of Sinclair computer ownership (and I'm "only" 37) have I ever opened one up to take a look inside... until yesterday evening, so it should not be assumed I know what I'm doing. I know what a capacitor is, for instance; I know what a soldering iron is, and I can just about use one to very crudely connect two electrical wires, but it absolutely defies all my belief how the tiny solder dots on a circuit board can ever be made with the precision required that I've never been able to achieve in about two and a half decades of trying (still to this day, I can't fathom a way to get the solder to stick to the copper wire better than it does to the soldering iron, thus destroying the connection I thought I'd just made).

    But onwards anyway...

    Try giving the tails of the keyboard membrane a clean with a very light abrasive, such as a "blue" rubber or even just a bit of kitchen paper towel.
    Right, I'd assume that means disconnecting the keyboard from the top cover, and I'll take a look what's there.

    Where two precariously thin ribbon cables attach to the circuit board, the one nearest the bottom edge is leaning over at an angle that would make even the residents of Pisa twitch a bit. Might that also be an issue here?

    The wire with one end free should be connected to ground. It's normally put under one of the screws that goes through a silver pad in the PCB, just above where you have labelled the loose screw. It's likely that screw is loose because someone has incorrectly put a slightly longer one in. The missing screw often seems to be missing and will cause no harm
    I figured it was a ground connector, it's just that there doesn't seen to be anything to connect it to - one end is screwed (almost) to the metal casing of the disc drive, the other... hangs loose, and I can't see where this silver pad is supposed to be. I can make sure the loose screw is tight by shoving a washer between the ring and the screw head - I've got a load of M3, and they should be small enough to fit.

    Point taken about the missing screw, at least when the case is fully secure there are three screws holding the drive in.

    Also, I've just had a look at the +3 booting up with the case off - I can hear the disc drive whirring but I can't see any moving parts while the whirring sounds, or a belt, or anywhere the belt should go. I had this horrible sinking suspicion that the belt would be buried under the circuit board and what do you know, my suspicions are right. Even with the annoyingly small diagrams I'm tempted to have a go myself, but where I've got one voice in one ear saying "come on, it's easy, even a chimpanzee could do this" I've got another voice in my other ear saying "you with your clumsy sausage fingers and notoriously shaky hand, you remove one screw from that drive and it'll be destroyed forever!"

    While I'm talking about disc drives, as well as having no games on disc, I don't have any blanks. I know there are the SD/DD/HD formats for 3.5", but did the Amstrad CF-2 also have different densities? I'm looking at these, for instance: http://www.ebay.co.uk/itm/4-x-CF-2-Floppy-Discs-Disks-with-Cases-Amstrad-CPC-PCW-464-6128-Spectrum-3-/371871687672?hash=item569547a3f8:g:Ko0AAOSwx6pYqe2f
    The auction says they've been used on an Amstrad PCW, but am I right in thinking they can be formatted for the +3?

    1024MAK wrote: »
    1> The Amstrad 40077 gate array chip does the decoding/encoding of the keyboard and joystick inputs... Schematics for the ZX Spectrum +2A/+3, +2B, and +3B here. Keyboard matrix here. I can only suggest you test the PCB tracks (traces) between the connectors (keyboard "KBY3", joystick pin 9,) and the pin of the gate array chip (pin 30) plus the associated resistor (R11).
    ...and this is why I put that disclaimer at the start of this post, because any assumption I have any kind of knowledge and skill of electronics beyond "I can make a crystal set" will be very wide of the mark. If I'm walked through it step by step it might be possible. The important word there is "might".

    I can do said testing as long as I know what I'm testing for, and how to do it - I can poke around with my trusty Gunson's pocket multimeter, presumably set to one of the resistance settings, but other than testing the actual resistance of R11 (which I've found and *should* be able to decode the coloured bands - the gold one comes last, right?) I'll have no idea which range I'm supposed to be testing in and what readings I'm supposed to get for a working or failed component. It's like when I've tried to use the ohmmeter to check for a blown fuse - if it's blown, the resistance will be infinite and no range will read anything, but does anyone know off-hand the resistance of a working 3A, 5A or 13A fuse? I certainly don't.

    I also took a look at the chips and to my absolute horror I find the 40077 is the deepset chip in the middle with the huge number of pins - I thought if it was faulty it might be a case of pulling it off and replacing it with the equivalent from the +2A (the one with the dodgy modulator that I could stand to use as a sacrificial lamb). No chance. If that chip's gone it's game over, do not insert any more credits.

    At least, looking through the schematic, I can see pin 30 on the 40077, I can see pin 9 on both joysticks, and I can see KBY3 and they're connected in a "TT" shape. It's just a matter of seeing how that translates on a screen to what I then see on the circuit board, where I have a dreadful habit of not being able to see the wood for the trees...

    Is there a chance I might have to take out the circuit board and take a look underneath? That is a prospect that has the "you'll wreck it" voice shouting very loudly.

    2> The Tape/Sound jack socket on any +2 is only wired for sound out. Unless the computer is modified, it is not possible to use an external tape deck to load programs and games using this connector.
    I thought as much - I knew that was the case with my original +2, but thought there was a chance that the "+3 with a tape deck" might still have retained an extraneous piece of its +3ness. No such luck.

    Right... 3 am... I will be dreaming of circuit diagrams for the rest of the night.
    Post edited by The Mighty Dopethrone on
  • While I'm talking about disc drives, as well as having no games on disc, I don't have any blanks. I know there are the SD/DD/HD formats for 3.5", but did the Amstrad CF-2 also have different densities? I'm looking at these, for instance: http://www.ebay.co.uk/itm/4-x-CF-2-Floppy-Discs-Disks-with-Cases-Amstrad-CPC-PCW-464-6128-Spectrum-3-/371871687672?hash=item569547a3f8:g:Ko0AAOSwx6pYqe2f
    The auction says they've been used on an Amstrad PCW, but am I right in thinking they can be formatted for the +3?

    Correct, there were no high density 3" drives. The only difference is the format the data is stored in.
    It's like when I've tried to use the ohmmeter to check for a blown fuse - if it's blown, the resistance will be infinite and no range will read anything, but does anyone know off-hand the resistance of a working 3A, 5A or 13A fuse? I certainly don't.

    At their rated current and below, the resistance of a fuse should be zero, ideally. Above that they should blow and go open circuit (infinite resistance).
    I also took a look at the chips and to my absolute horror I find the 40077 is the deepset chip in the middle with the huge number of pins - I thought if it was faulty it might be a case of pulling it off and replacing it with the equivalent from the +2A (the one with the dodgy modulator that I could stand to use as a sacrificial lamb). No chance. If that chip's gone it's game over, do not insert any more credits.

    I don't think you'll have to go that far. A word of warning though, it's very easy to accidentally lift traces/vias on the Amstrad designed +2/+3s boards, just something to be very wary of when lifting/removing components.
  • edited February 2017
    +3 rehab update:

    With a lot of time to myself this morning (unfortunately...) I thought I'd dig a little deeper into the innards of the +3. The first place I looked was Dataserve Retro's +3 disc drive servicing guide - it is a lot easier to follow and the challenge is a lot less daunting once I get stuck into it. And, to nobody's surprise whatsoever, the drive belt had completely vandalised itself. Fortunately none of it was stuck to the main pulley, just the metal capstan, so I've given that a good clean and it'll be ready for a new belt once I get one ordered. I've cleaned the read/write head as well, the write protect pin is firmly intact - and I've located the silver pad on the circuit board that Peter mentioned above, though by the looks of things (i.e. from Dataserve Retro's pictures) this wire was never connected in the first place...

    It isn't such good news with the keyboard, though. I took it apart, examined the membrane, wiped the dust off, but couldn't see anything obviously wrong here. I tried wiping the tails with kitchen paper as Peter said. I have no idea why this never occurred to me last night - the aforementioned "sacrificial lamb" +2A has a perfectly working keyboard, so why don't I just swap the keyboards over and see what happens? The tails on the +2A's keyboard are in considerably worse condition than the +3's - there's black muck on the Keyboard X connector - but I gave it a clean anyway, installed it in the +3, and... the eight "IN ***** = 187" keys still weren't working. It's a problem with the circuit board, not the keys. Bah, humbug, and assorted other boiled sweets. I've changed them back again, so the worse-condition parts stay with the worse-condition computer.

    When I said one of the connectors was leaning over at a worrying angle on the +3, I can now see it's the Keyboard X slot that's doing that - Keyboard Y is standing up straight, but that's the one with the problem. At least the disc drive is ready to accept a new belt straight out of the bag. Maplin will have Servisol contact cleaner tomorrow so I'll give the Keyboard Y slot and TAPE/SOUND socket a good blast with that - you never know what it might fix, and I've got plenty of other sockets that might want some attention from it.

    Extra bonus good news: on opening the +2A and examining the cassette mechanism, I found out how the spring in the door works - it's just a stiff piece of wire behind a plastic hook. So I opened my 29-year-old +2... what do you know, the wire had come unhooked! Easiest fix in the world, that one, and so the eject button works on it for the first time since about 1992. Marvellous.

    Looking on Dataserve Retro's +3 spares shop, I can see a lot of useful stuff that I'll hold off buying until I know exactly what I'll need. I see twin drive belts, a replacement TAPE/SOUND socket and a Disc Doctor program - which comes on a disc, just like I don't have, which I suppose kills two birds with one stone! Also, the mounting bar (which I don't need) comes with the two screws that I need one of, and - can anyone confirm - is it the same screw that mounts the earth wire to the circuit board?
    Post edited by The Mighty Dopethrone on
  • +3 rehab update again:

    I obtained the contact cleaner - had to go to Loughborough for it, but no biggie. I gave the TAPE/SOUND socket and Keyboard X and Y slots a good, hard blast with it, left it for an hour and wondered why it hadn't dried. I then searched for what I'd bought (Servisol Super 10 Switch & Contact Cleaner) and found it had an oily lubricant for switches and relays. Cue rising concern that what I now had was a ruined board. But after about an hour of careful washing and even more careful drying of the motherboard with generous amounts of isopropanol, the yellow oily residue was gone, and when it was dry I put it all back together and plugged it in...

    Rather than having a completely ruined +3, I now have one with a fully functioning keyboard! Congraturation, I sucsess.

    What remains now is to order those bits and pieces from Dataserve Retro to get the job nearer completion, and I will have a +3 that works with discs (I'm looking at some on eBay, and if I win them I'll be able to FORMAT them now that I have a working "M" key). To have it working with tape is still a potential problem - even after the contact cleaner I could still see something black on the contact inside the TAPE/SOUND socket, and all I could find to get in there and attack it further was a wooden cocktail stick soaked in isopropanol. Even after physical treatment, the sound coming through that socket is still ruinously awful and the +3 doesn't recognise loading tones in any way.

    I'm not particularly good at soldering, either, and that's what replacing the socket involves. But I'm not going to have the Congraturation sucsess train stopped at this point.
  • edited February 2017
    Hey, even for us hardware nerds, sorting out poor contacts in a 3.5mm jack socket is not a run of the mill job :-(

    If I need to do it, you will see me attacking it with some "watchmakers" screwdrivers...

    Mark
    Post edited by 1024MAK on
    Sinclair FAQ Wiki
    Repair Guides. Spanish Hardware site.
    WoS - can't download? Info here...
    former Meulie Spectrum Archive but no longer available :-(
    Spectranet: the TNFS directory thread

    ! Standby alert !
    “There are four lights!”
    Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
    Looking forward to summer in Somerset later in the year :)
  • Whichever plug I put into the EAR socket, red or white, I was treated only to the sound of an unoiled chainsaw trying to hack through concrete.

    That sounds about right for a +3. Distorted sound is normal. Adjust the volume on the tape deck until you get the red/cyan leader to be detected. Start low volume and increase. You might end up only just getting the red/cyan bars at max volume. Ear sockets on tape decks past the 90's, came under the hammer of health and safety, so you can't get enough volume to deafen you. Which is what the speccy needs.
  • Just wondering is the device your using a stereo or mono device. Possibility if it's stereo, you might be shorting a channel to ground if a mono plug is inserted in a stereo headphone jack socket. Check you leads again. I understand your using a 3.5mm to 2 phono plugs, does 3.5mm plug have 3 contacts separated by 2 black rings like this:-
    3.5mm_stereo_plug.jpg

    That's the correct stereo one (2 channels 1 for ear(load), 1 for mic(save))needed to plug into the +3 tape/socket. Next I understand your using a phono to 3.5mm adapter. Again does the adapter have a stereo 3.5mm plug as shown above? If it only has 2 contacts separated by 1 black ring, this a mono plug:-
    3-5mm-Mono-Plug-Connector-Plastic-1.jpg

    If the mono plug is inserted in a device which is stereo, it will short the right channel to the ground connection. This will cause poor distorted sound, and low output. There's also a possibility of damaging the amplifier of the stereo device too.

    If your adapter has a stereo 3.5mm plug, no worries as long as all the adapter is doing is splitting the stereo output to 2 mono left/right phono connections. Usually having a red and white phono sockets would confirm this. If it's any other colour, possible it may be for use with another device, and may be wired differently. A cheap multimeter is handy here using the continuity test function to see what and where is connected to if unsure.

    Now on the Magic Cube all-in-one system your using, is it stereo or mono only. Usually a stereo device would have 2 speakers, a mono only 1. Another way to tell is simply plugging in a pair of stereo headphones. Is the sound coming out of both or just one of the headphones. Both is stereo, one is mono.

    Assuming you are using the correct cables and device, only connect one phono plug into the adapter at a time. What your doing here is trying to find the channel for the ear(load) connection. If you hear loading noises, but the +3 is not responding with loading bars, or border flashing red/blue, you have found the connection for mic(save), which you don't want. Unplug and try the other phono plug. This should be for the ear(load) connection, and you should hear the loading noise again, but this time the +3 should respond with loading bars if the volume level is ok on the device your using. If not it still should make the border flash red/blue.

    Long post but hope it's understandable and helps yourself and others. Don't understand why theres no stickies here going into these details how to connect devices and correct leads. I'm sure it would help many folks coming back to their Spectrums.
  • Your Spec-chum, the long and short of this is: the Magic Cube is most definitely mono (there isn't even a way to get stereo sound out of it), so what I started with is a mono-to-mono lead that didn't do the job, as you say it wouldn't. Right now I don't have a lead that's 3.5mm stereo to two 3.5mm mono plugs, so I improvised with the 3.5mm stereo to red & white RCA plugs and found two adapters to convert the RCA plugs to 3.5mm mono. This still isn't working in the +3.

    The lead I'm now using is wired thus:

    be0ba65b_stereo-plug.gif

    Left channel: 3.5mm tip to white RCA tip
    Right channel: 3.5mm ring to red RCA tip
    (and presumably the ground of both RCAs is wired to the same ground contact on the 3.5mm sleeve)

    Now, what you've said here is interesting...
    That's the correct stereo one (2 channels 1 for ear(load), 1 for mic(save))needed to plug into the +3 tape/socket.
    ...
    If your adapter has a stereo 3.5mm plug, no worries as long as all the adapter is doing is splitting the stereo output to 2 mono left/right phono connections. Usually having a red and white phono sockets would confirm this.
    ...because the diagram in the manual I'm looking at (page 317) shows the tip of the 3.5mm stereo plug marked as "audio output" and the ring as "not used". So I thought: "hang on a minute, does this mean that the +3 both receives and accepts sound through the same channel when the tape recorder is connected?"

    On further consideration, because it's under the "amplifier" section of "connecting peripherals" does this diagram only refer to the sound output to the amplifier? So, when conducting tape operations, does it use the whole socket - which, logically now, would be:
    Tip = audio out = left channel = white RCA = SAVE tone to MIC
    Ring = audio in = right channel = red RCA = LOAD tone from EAR

    That way, at least with the RCA lead I'd know it's the red plug I need from the EAR socket.

    Assuming you are using the correct cables and device, only connect one phono plug into the adapter at a time. What your doing here is trying to find the channel for the ear(load) connection. If you hear loading noises, but the +3 is not responding with loading bars, or border flashing red/blue, you have found the connection for mic(save), which you don't want. Unplug and try the other phono plug. This should be for the ear(load) connection, and you should hear the loading noise again, but this time the +3 should respond with loading bars if the volume level is ok on the device your using. If not it still should make the border flash red/blue.
    Thing is, no matter whether I plug the red or the white RCA (adapted, obviously) into the EAR socket, I hear the same sound coming from the +3 - whether it's a ruinously distorted version of Iron Maiden, or whether it's a loading signal that the +3 doesn't recognise. I know when one of them was plugged in and I tested the tape player with Psion Scrabble (which loaded perfectly on the +2, +2A and +2B) there was the very briefest flash of red border (a fraction of a second) at the very beginning of the (horribly distorted) pilot tone, then it reverted to white and the picture on screen distorted slightly (it was almost as if there was a ghost picture of the ZX81 pilot tone stripes overlaid on it).

    The 3.5mm stereo to RCA lead I'm using comes from some PC speakers I had a while back - the lead was to connect the stereo sound output from the PC to the speaker that contained an internal amplifier, that speaker would play one channel, then the sound for the other would be routed to the other via a mono lead with a brown RCA plug on each end. I've used this lead to connect other devices (tape deck, record player, other PC) into the Mac's stereo-mic-meets-line-in socket to make digital copies of tapes, records, etc - and it's always worked fine, it has no extra blobs with in-line resistors in it, it's just an audio lead.

    Nevertheless, while I can see no reason why the lead I'm using wouldn't be suitable, I've ordered a TAPE/SOUND lead from Dataserve Retro amongst all the other stuff, which has two 3.5mm mono plugs coloured red and white. I'd hope they're coloured the same way round as the RCA plugs so that it's red to EAR and white to MIC!






  • Well...

    For good measure, I've tried a different 3.5mm stereo to red-and-white RCA lead. Knowing now that it's the red plug that connects to the EAR, let's try loading a game that I know works on the +2B. Psion Scrabble should do it. Loading from tape on the +3, red lead into the Magic Cube, in 48K mode to start with...

    Crikey! IT WORKS!

    ...sort of. I get the pilot tone, I get the red and cyan stripes on screen. I get the loading noises, I get the blue and yellow stripes. The game loads... it just doesn't execute at the end, the loading screen stays on.

    Maybe the other lead was duff, though playing music or loading tones into the +2B with that lead seemed to sound OK. I may have mentioned (probably on the other thread) giving the TAPE/SOUND socket a good scrape out with a cocktail stick soaked in isopropanol, I'll bet that's helped (and the mild abrasive effect of the wood should have done the job even if it was dry). Dataserve Retro's site does mention bending the contact pins back in if the plug is loose in the socket, but it isn't. Even so, it looks like I've ordered more stuff from them than I really need, but the whole package is under 20 quid and I know I'll spend more on beer and curry this weekend than I have there.

    I'm getting there, although it's clearly not 100% still. I'll experiment with some other 48K games first on both the +3 and the +2B (a better bet for what should work on the +3 than if I used the +2) and see what I can get working.
  • Now, what you've said here is interesting...

    ...because the diagram in the manual I'm looking at (page 317) shows the tip of the 3.5mm stereo plug marked as "audio output" and the ring as "not used". So I thought: "hang on a minute, does this mean that the +3 both receives and accepts sound through the same channel when the tape recorder is connected?"

    Are you looking at a +2A manual?
  • No, it's the +3 manual. I think by "Not used" for the ring part of the stereo plug, it means "not relevant to this section", which is where I was confused.

    Anyway, I've been testing the +3 with the six games that came packaged with the +2 - mainly because in my cornucopia of second-hand stuff I had the six tapes in their original +2-branded box, were probably duplicates when their original owner bought them, and are somewhere approaching "new old stock". They all load perfectly into the +2B, and do so into the +3 as well. So the TAPE/SOUND socket is good, the lead I'm using is good, the tape deck is good (for something built circa 1980) and all that isn't good is Crazy Golf, which is just as much of a clunker now as it was then!

    I'm going to test the +3 further with 128K games to see what it can do there (and I know there will be pitfalls), and also see how well it saves (the erase head on the Magic Cube's tape deck should be fine, I see no reason why it would ever have been used for recording anyway) but as it stands I think I'm just one disc drive belt away from having a fully working +3, as it was in 1987.

    Even so, the sound upgrade I've mentioned on the other thread wouldn't go amiss!
  • I load from tap/tzx to the +3 via my PC. I load in Spin or SpecEmu with auto start/stop turned off, turn the volume up, and my speakers down. I can even get crazy speed loaders to work this way. For example this loads fine.
    https://www.dropbox.com/s/azzi88mg5ilvk8e/Manic_Miner_033.tzx?dl=1
    6000 baud z802tzx loader.
  • Well done for keeping at it mate, I'm sure you'll soon have fully working machine. The +3's tape/sound socket is a stereo, 2 channel one yes. One for ear(load) connection, other for mic(save) connection. Might be wrong but I'm sure in +3 manual, it mentions on the page regarding the tape/socket, not to insert a mono jack plug into this socket.
  • ...because the diagram in the manual I'm looking at (page 317) shows the tip of the 3.5mm stereo plug marked as "audio output" and the ring as "not used". So I thought: "hang on a minute, does this mean that the +3 both receives and accepts sound through the same channel when the tape recorder is connected?"

    On further consideration, because it's under the "amplifier" section of "connecting peripherals" does this diagram only refer to the sound output to the amplifier? So, when conducting tape operations, does it use the whole socket - which, logically now, would be:
    Tip = audio out = left channel = white RCA = SAVE tone to MIC
    Ring = audio in = right channel = red RCA = LOAD tone from EAR

    That way, at least with the RCA lead I'd know it's the red plug I need from the EAR socket.
    Err, read all the text on that page in the manual...!!!
    When using an amplifier, it is worth remembering that if you have connected a cassette unit to the +3, the tape 'load' and 'save' signals are also fed to the TAPE/SOUND socket"....
    A better diagram is on page 311 in chapter 10 ;-)

    Mark



    Sinclair FAQ Wiki
    Repair Guides. Spanish Hardware site.
    WoS - can't download? Info here...
    former Meulie Spectrum Archive but no longer available :-(
    Spectranet: the TNFS directory thread

    ! Standby alert !
    “There are four lights!”
    Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
    Looking forward to summer in Somerset later in the year :)
  • 1024MAK wrote: »
    A better diagram is on page 311 in chapter 10 ;-)
    That's what I wanted in the first place!

    Anyway, I did get the tape connection going with the old lead - but this morning, a package came through from Dataserve Retro. I now have a proper tape connection lead... which has the colours the other way round from the RCA plugs so it's white for EAR and red for MIC (and I can't have them plugged in both at the same time on the Magic Cube because the sockets are on opposite sides!) This is working fine now, I've fitted my drive belt, tried it with the Disc Doctor program, and the conclusion is...

    For the first time in my life, I have a fully functioning +3!

    Now all I need to do is get the sound upgraded for good measure, and find a few more games that will work with it from tape. So far I have Defcom, Toyota Celica GT Rally, Auf Wiedersehen Monty, and a long list of failures from Codemasters games...
  • It's not normally a good practice to connect the "ear" and the "mic" leads/connectors at the same time. Because if the recording device (cassette tape recorder) provides an audio monitor output, this messes up the levels of the save signal that the Spectrum outputs.

    Mark
    Sinclair FAQ Wiki
    Repair Guides. Spanish Hardware site.
    WoS - can't download? Info here...
    former Meulie Spectrum Archive but no longer available :-(
    Spectranet: the TNFS directory thread

    ! Standby alert !
    “There are four lights!”
    Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
    Looking forward to summer in Somerset later in the year :)
Sign In or Register to comment.