ZX Spectrum + alive thanks to this site.
I was given a dead unit several months ago. I finally had time to look at it yesterday. Using the repair guide on this site the thing is now alive. One 7805 and one ztx650 tr4 and it is all good.
I have never owned a Spectrum before so I am at a loss as to what to do with it now. Any recommendation are gladly received.
P.s It is missing the break key and the space-bar is wobbly. Has anyone got any spare Keys?
Cheers
I have never owned a Spectrum before so I am at a loss as to what to do with it now. Any recommendation are gladly received.
P.s It is missing the break key and the space-bar is wobbly. Has anyone got any spare Keys?
Cheers
Post edited by 68k-dude on
Comments
All depends what you want to do with it really. If you want to play games, then the world is your oyster really. Which version of the Spectrum do you have? Does it have a built in tape deck? If not, get yourself an old tape deck, some mono 3.5mm jacks, and then you cvould get some games from ebay, for example. There are people that sell games on here as well, who may even guide you as to what good games are.
If you want to try programming there are plenty of books to point you in the right direction.
As for the keys, I'm sure somebody on here may have a dead donor machine.
The main thing is to have fun with it.
Ah, I see now, its is probably a 48K +, so you will need the tape leads. Easy to make, or can get them from dataserve retro or rwap. I think they also do tape decks, if you need one. The type I've heard that dataserve sell is very good, I have one like it and loading is never a problem. (Sony TCM).
Thanks for your reply. it appears that some other things are missing. The fold out legs, which aren't that important. The heatsink for the 7805 is missing, which is a little more important. I only realised when I saw a picture of an open unit. I'll have to make one. The legs are a little more difficult to make.
The PCB is an issue 3B. However it has had some modifications. The ULA chip is a 6C00IE-7 and the CPU seems to be a later replacement.
Thanks again.
He sorted me out with spare legs for my spectrum+
<plug alert>
Regarding regulator heatsinks you might be interested in using a heatsink-less high efficiency DC-DC converter IC like the ones I'm currently selling for ?6 each :)
</plug>
If it hasn't been done already, another modification you may wish to consider is the composite video mod. It improves the picture no end, and allows you to plug your spectrum into the yellow video RCA socket usually on the front of a TV. Another good advantage of this is that you can make a lead with a 3.5mm mono jack on one end, and an RCA plug on the other. Take the 3.5mm end and plug it into MIC, plug the other end into the white RCA socket on the TV and now you have volume controllable sound on your TV rather than using the beeper in the Spectrum itself, mine are all very quiet, so this works well.
If you want to play games with a joystick you will need an interface, but careful with that, it plaugs into the Spectrums achilles heel, the dreaded edge connector. If you get one, never ever, plug it in or out with power on, you WILL kill your spectrum that way. Apologies if you know that already, but it has happened so many times. Apparently there is a way of hardwiring a joystick to the motherboard, personally I'd be a little wary of that, unless I had a very good way of making sure that it couldn't be pulled from the outside, as you may just replicate edge connector disaster - or worse.
I assume this would be installing a "sinclair" joystick interface, as found on the 128k machines. If you added a joystick socket to the case somewhere this could be wired up securely inside with no problems.
You could try the pokes/peeks here to make sure your upper RAM is working fine:
http://www.worldofspectrum.org/SpectrumRepairGuide/#sdocsf
You might want to get a heatsink or regulator replacement first of course. I probably have a spare heatsink if you need one, and the keys you require if nobody else can supply them.
For the wobbly space bar, check that the tabs underneath the bar aren't broken, and that the metal bar is in place properly.
If you can't get hold of a tape deck and games, you could load them from a PC soundcard using a lead with a 3.5mm jack on both ends.
John
I seem to recall what I saw was rather more basic than that, and involved soldering wires direct to the board, quite where, I don't have a clue, but I'm not sure it's to be recommended. Your solution sounds alot better.
Well it would be the same circuit... I'd never suggest soldering a cable directly to the board inside as it's almost guaranteed to get pulled by accident and rip the wires off the board. Trouble is that anything that needs a socket adding means chopping a hole in the case
For the sake of a few pounds they could have easily included a built in interface. Even when Amstrad took over they were wired up for their joysticks. Talking of which I must get an adapter for my +3, as I would prefer to use tha than an interface on the edge connector of my 48K or +.
A few pence. The sinclair interface has a diode and a plastic 9 pin D socket for each joystick.
It's a case of thinking of it when the computer is being designed. Don't forget the spectrum was intended for business and education. By the time the 128k came out it was obvious that games were most of the market.
Well I was going to say a few pence, but thought better of it. They must have been quite deluded to think that any office worker, let alone businessman would use a keyboard like that for long. Commodore had already pretty much tested the market by the time the Spectrum came out, not saying they got it totally right, but at that stage, they seem to have been nearer the mark.
As bad as it is to use though, rubber key spectrums are a design icon of the 1980s, less so the +, but still a good look. The Amstrad models were just practical.
Also. Many thanks for all of your input. I will most likely go on a mod hunt to see what is available. The composite video mod is going to happen.
Many thanks.
I'll try this.
Now a win.
There are plenty of free image hosting websites out there, so upload your picture to one of them and then link to that address instead.
You can use this http://www.postimage.org
here are my albums
p.s That heatsink gets hot. I'm glad I made it as big as I could. I may go for a different regulator, as recommended by Alien 8.
Did I recommend a different regulator? I remember I had a big discussion on here some time ago when I was having problems with my Spectrum and a DivIDE+ interface. In the end we just changed the 7805 for a new unit, it didn't have the desired effect unfortunately. Was it that discussion that you were referring to?
I got my new keyboard membrane from RWAP about 5 yeras ago, it was only about ?6 (may be more by now), but I found it easy to fit, and it has lasted very well. I have dissected that spectrum multiple times, and it is still working well.
lets see if I can help =)
Keyboard Membrane
Theres a few sources, but I will recommend rwap services on this one, I have done some business before and I am pleased with the service and communication =)
you can fidn the membrane's (click here) at the bottom of the page =)
Regulation
have a chat with guesser as he is selling some drop in replacements (click me) that are much better- the 7805 regulator is about 55% effcient in converting the power - this means that about 45% of it is turned into heat!
The replacements are 94% effcient - thus only 6% will be thumped out in heat and providing nice smooth power rails =) .
Alternatively you could look at sourcing some 74S805's - but these also lump out a fair bit of heat under load.
there that should do it.
Now for the not so good bit.
While the unit powers and displays fine the memory test found below returns the system memory as 16kB. The upper 32kB is invisible to the system.
http://www.worldofspectrum.org/SpectrumRepairGuide/#sdocsf
I now have more fun in stall.
What type of RAM chips are on your board? I probably have suitable spares if you need them.
Thanks for your kind offer of replacement chips.
Using the fault finding tables it transpired I had a problem with IC18. I had a look through my boxes of components and found a TMS4256-12 part. The same pin-out as the original only a more ram. I thought it would do the job as the most significant address bit would be pulled down.
After fitting it I now have 65535 returned by the commands. Yay, I have a 48k spectrum instead of a 16k one. Winner.