I want to take the innards out of a Spectrum+ and put them back in a rubber key case. Can I just snip the reset switch wires on either side of the capacitor/transistor thingy and it’ll be fine? Or do I need to do something else?
Does it make a difference if it’s an upgrade or an ‘original’ plus?
(PS. You can probably tell that I know nowt about electronics, so please be patient with my ignorance…)
Random reset switch question.
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Ast A. Moore
- Rick Dangerous
- Posts: 2644
- Joined: Mon Nov 13, 2017 3:16 pm
Re: Random reset switch question.
Yep. Go ahead and clip them. No, there is no difference between the regular and “plus” boards, as far as the enclosure “downgrade” is concerned.
Every man should plant a tree, build a house, and write a ZX Spectrum game.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Re: Random reset switch question.
Cool thanks.
Re: Random reset switch question.
Just remember to cut the red wire first...
I know it's important. I see it in a lot of movies.
I know it's important. I see it in a lot of movies.
Re: Random reset switch question.
I know you probably have your reasons, but it may be worth considering fitting a reset switch to your rubbery-keyed case. One of those small momentary switches like this:
Will just about fit to one side of the existing modulator, obviously small hole will need to be made for said switch. Most seem to have a red button but you can get the black button one without too much trouble, as long as its a "push to make" not a "push to break" one! I did do this to one 48K I had, its a slight squeeze but it can be done and its out the way on the back too, no accidental pressing!
Just a random thought, nothing more.
You may not want a switch / cut the case / may have an interface with one etc etc.
Will just about fit to one side of the existing modulator, obviously small hole will need to be made for said switch. Most seem to have a red button but you can get the black button one without too much trouble, as long as its a "push to make" not a "push to break" one! I did do this to one 48K I had, its a slight squeeze but it can be done and its out the way on the back too, no accidental pressing!
Just a random thought, nothing more.
You may not want a switch / cut the case / may have an interface with one etc etc.Re: Random reset switch question.
Hmmm. Thanks for the idea. Might just do that….
What do you mean by ‘push to make?’ Like ‘break’ is break the circuit?
What do you mean by ‘push to make?’ Like ‘break’ is break the circuit?
Re: Random reset switch question.
Yes. For the 'single pole' type of switch here (two contacts only) its typically a choice of two, I'm excluding the "changeover" ones (which have three contacts) and "double pole" which are two sets inside one unit.
Anyway:
Push to make: The connection is only made when the button is pushed. < This is what you want for the reset switch. Sometimes called "N.O" (normally open)
Push to break: The connection is always made unless the switch is pushed, then its open/not made. < These are a bit rarer but can be easily mixed up in a box in a shop etc if not careful as they look the same! Sometimes called "N.C" (normally closed)
Another easy way to think of it, if you had a bulb + battery + switch wired up, with a "push to make" the bulb would only ever light when you pressed and held the button. If you used a "push to break" switch the bulb would be lit all the time until you pressed and held the button.
Sorry if I've over-simplified it
, easier to type stuff you don't need to know / you already know than have to type it later. EDIT... Tidied post a bit. I'm not great at explaining this in words, sorry.
Re: Random reset switch question.
Don’t worry, no chance of oversimplification where I’m concerned! And in my experience nothing is as simple in electronics is it first seems…
One more question, if it’s push to make then what are you ‘making’ when you push the Speccy reset switch? I assumed that you would be ‘breaking’ something by pushing the switch ie. cutting the power, like when you pull out the power plug.
One more question, if it’s push to make then what are you ‘making’ when you push the Speccy reset switch? I assumed that you would be ‘breaking’ something by pushing the switch ie. cutting the power, like when you pull out the power plug.
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Ast A. Moore
- Rick Dangerous
- Posts: 2644
- Joined: Mon Nov 13, 2017 3:16 pm
Re: Random reset switch question.
Well, no. While you can reset the Speccy by literally pulling the plug on it, the actual reset switch fitted on later models does something else. It temporarily bridges the connection between a special reset pin on the CPU to ground. That signals the CPU to start executing code from address zero. Incidentally, when the CPU is powered on, it does the same thing (well, almost, but we don’t need to go into much detail). So, yes, when you press the reset switch, you are making a connection in this case, rather than breaking one.
Every man should plant a tree, build a house, and write a ZX Spectrum game.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Re: Random reset switch question.
Well I’ve learnt something today! 
Re: Random reset switch question.
Beat me to it, sorry.
I was going to say you're 'making' the connection between a "reset" pin on the processor with that switch, you're (iirc) joining pin 26 "RST" on the Z80 CPU to 0v (usually pin 29 again iirc)
A push/break switch in theory you could add to the (low voltage!) power supply side just before the plug in the Spectrum but that would only really be the same as removing and re-inserting the power plug very quickly, possibly so quickly it may not reset. Please don't do this!
I was going to say you're 'making' the connection between a "reset" pin on the processor with that switch, you're (iirc) joining pin 26 "RST" on the Z80 CPU to 0v (usually pin 29 again iirc)
A push/break switch in theory you could add to the (low voltage!) power supply side just before the plug in the Spectrum but that would only really be the same as removing and re-inserting the power plug very quickly, possibly so quickly it may not reset. Please don't do this!