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ZX Spectrum 48K Issue 3, loss of -5V rail.Hi all, I've googled this problem and poured over the electrical diagrams for the circuitry concerning the power supplies and I believe I know what …
What is the voltage from the PSU? I am assuming 12V?
I had a PSU producing 14v under load and this stopped TR4/5 working and caused the loss of the -5v rail.
Anything over about 13.4v causes issues.
BP -
ZX Spectrum 48K Issue 3, loss of -5V rail.Hi all, I've googled this problem and poured over the electrical diagrams for the circuitry concerning the power supplies and I believe I know what …
... have -4.40V on the -5V rail.
I have ... under load measures something like 12V, but when I measure directly ... see what is on the -5V rail (to confirm one or ... -
Zx Spectrum 128k Toaster RGB pinoutHi all When I use my +2 scart cable on my 128k the picture looks terrible, so I have bought the din plug to make my own. Most sites from what I ca…
... an external 12V power supply. I personally use the +5V from the ... -
ZX Spectrum 48K Issue 3, loss of -5V rail.Hi all, I've googled this problem and poured over the electrical diagrams for the circuitry concerning the power supplies and I believe I know what …
... board needs -5v, and the only other IC needing +12v is the ... LM1889 video encoder, without +12v you'll get a black ... -
Powering a Spectrum with 5v?I live in the States, but I'm originally from England. My original Spectrum is still at my mum's house in the UK, and I was thinking of asking her t…
... the dram runs off +5v, -5v, and +12v. The latter two derived from ... it up with only the 5v rail the RAM would most ... -
Powering a Spectrum with 5v?I live in the States, but I'm originally from England. My original Spectrum is still at my mum's house in the UK, and I was thinking of asking her t…
... 9v to 5v, and then the 5v was stepped up to 12v to ... .
Isn't the 5v output from the main regulator ... -
Powering a Spectrum with 5v?I live in the States, but I'm originally from England. My original Spectrum is still at my mum's house in the UK, and I was thinking of asking her t…
... be used to feed +5V +12V and -5V to the ZX Spectrum, with ... -
Powering a Spectrum with 5v?I live in the States, but I'm originally from England. My original Spectrum is still at my mum's house in the UK, and I was thinking of asking her t…
... to 5v, and then the 5v was stepped up to 12v ...
Isn't the 5v output from the main regulator ...
The +12V and -5V (and the ~12V "AC") supplies are actually ... a connection to the +5V supply is to use ... a PSU that outputs +5v, +12V and -5V. And then some ... -
Powering a Spectrum with 5v?I live in the States, but I'm originally from England. My original Spectrum is still at my mum's house in the UK, and I was thinking of asking her t…
... be used to feed +5V +12V and -5V to the ZX Spectrum, with ... -
ZX Spectrum 48K Issue 3, loss of -5V rail.Hi all, I've googled this problem and poured over the electrical diagrams for the circuitry concerning the power supplies and I believe I know what …
BTW, if I powered up the board like this would it hurt in anyway?
Is some sort of screen display expected to show?
Now would be the time to check for correct -5v, +5v, 12v and 0v on the IC's link points? -
ZX Spectrum 48K Issue 3, loss of -5V rail.Hi all, I've googled this problem and poured over the electrical diagrams for the circuitry concerning the power supplies and I believe I know what …
There is no -12V DC on the expansion port / ... edge-connector. It is a ~12V pulsed AC signal.
5V and +12V DC.
For ... -
Youtube vids of US guy converting speccy into handheldDidn't see it posted here but thought it was a pretty interesting project. Part 1 and 2 here, more to follow. [youtube]6GcwcyL9LgM[/youtube] [you…
... new board only has a 5v supply and the encoder IC ... output to composite runs off 12v.
Wasn't a ... PCB as a 12v rail (as well as -5v) is produced by ... -
Youtube vids of US guy converting speccy into handheldDidn't see it posted here but thought it was a pretty interesting project. Part 1 and 2 here, more to follow. [youtube]6GcwcyL9LgM[/youtube] [you…
... industrial boards that are otherwise +5V only boards.
For ... -pol-1o-p-0-75w-12v/dp/2400809?in_merch=New%20Products ... -
Composite picture qualityI have read many many discussions here about the composite video modification of the Spectrum 16/48K models. I have choosen one of the simplest comp…
... four capacitors that "decouple" the +12V supply (C5 to C8 on ... looking at) that "decouple" the -5V supply will have very little ... does not use the +12V supply or the -5V supply.
cf to ide adpatorI recently got a divIDE and i just bought a cf to ide adaptor. I know i have to do something to the adaptor but i cant find what is needed. Any ide…
... or does it have one missing for a key position? There ... do which is to put 5v on that pin and some ...1st interface in 30 yearsHi all, The last time I built a ZX Spectrum interface was 30 years ago, so today I gave it a whirl with an external rom. Switchable in/out of course…
... be nice:-
[LIST][*]+5V, -5V and +12V supply okay LEDs (maybe use ...1st interface in 30 yearsHi all, The last time I built a ZX Spectrum interface was 30 years ago, so today I gave it a whirl with an external rom. Switchable in/out of course…
... be nice:-
[LIST][*]+5V, -5V and +12V supply okay LEDs (maybe use ... each LED output, as the 5v LEDs are horrifically expensive?
1st interface in 30 yearsHi all, The last time I built a ZX Spectrum interface was 30 years ago, so today I gave it a whirl with an external rom. Switchable in/out of course…
... ;786614]
[LIST]
[*]+5V, -5V and +12V supply okay LEDs (maybe use ...Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
... renewed the capacitors, and the 12v rail looks good, then I ... for the out of spec -5v line is the 5v1 zener ...Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
Sorry Mr B. But I'm contradicting some of what you have said :-P
If you are really concerned about the +12V and the -5V supplies, modify and upgrade it as per the instructions in the service manual :-D
[B][I]Mark[/I][/B]Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
... many peripherals use the +12V or -5V supplies. Most peripherals that use ... +9V and / or the regulated +5V supplies.
And no ...Short Circuit Damage?Hey Spectrum fans, Currently trying to diagnose what is wrong with my 48K Issue 4B ZX Spectrum. The initial problem was the fact it would not boot -…
... circuitry that provides the -5v and 12v supply voltages that these chips ...Spectrum 48k ProblemsHi all Got my 48k today but it's playing up abit... First time i turn it on it was like this: [IMG]http://s26.postimg.org/hlg9d3f3d/IMG_20140830_…
... is failing to provide the -5V supply that the 4116 RAM ... chips need. If this -5V supply is missing, the 4116 RAM chips ...Spectrum 48k ProblemsHi all Got my 48k today but it's playing up abit... First time i turn it on it was like this: [IMG]http://s26.postimg.org/hlg9d3f3d/IMG_20140830_…
... />
[I][B]Pin 1 (12v pin) is 12.13
Pin 8 (-5v pin) is -4.80
Pin 9 (5v pin) is 4.98[/B ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... is responsible for the 12V and the -5V that are needed for ... the 7805 superflous), the 12V and the -5V. Therefore he has used ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
Why don't you just check continuity from the various voltages at the rear connector to each of those 4 pins?
I see 0V, 5V, -5V, 9V, 12V and -12VFaulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... high voltage cusps on the +12V line, seenable only on an ... parallel) and check the voltages +12V and -5V at IC13.
H.Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... /> 0v =0
-5v = 1770
+12v = 354
+5v = 860
[/QUOTE ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... to DC converter to supply +12V for the video circuits ([URL ... is no need for a -5V supply, so no need to ...
