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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 …
If I checked correctly something must be definitely wrong.
On the expansion board pins -12v is measuring 12v and 9v is measuring almost 12v? :-o
Zorn, where are the check points on board to look for the voltages, please? -
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 …
... from it to check output voltages.[/QUOTE]
You can ... -
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 …
Check the voltages at both ends of resistor R55 please.
[B][I]Mark[/I][/B] -
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 …
[QUOTE=1024MAK;784040]Check the voltages at both ends of resistor ... -
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 …
... .
Yes, double-checked voltages and readings are the same ... -
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 …
Okay, I was expecting voltages somewhat different to -1V approx. ... I was expecting voltages around -5.1V.
ZX Spectrum 48K AV IssueOK so I dugout my old 48K Speccy today and decided to AV mod it. I did the mod (pretty easy) but the picture I am getting is this. [url=http://posti…
Yer I getting the correct voltages
I kinda, I get the same but I don't get the coloured bars that pop up every so often just the squares.Spectrum & ZX81 PSU Strange VoltagesHi all I've just refurbished my ZX spectrum PSU after i accidently broke one of the wires i soldered the joints to the PCB nicely and all seems to b…
... not uncommon to measure high voltages with no load with these ...Spectrum & ZX81 PSU Strange VoltagesHi all I've just refurbished my ZX spectrum PSU after i accidently broke one of the wires i soldered the joints to the PCB nicely and all seems to b…
Ohhhh that makes sense then! thanks for clearing that up.
I presume then that even at these voltages these 2 are safe to use? Hopefully they will drop enough to not cause harm.
I don't want them killing a speccy or my ZX81.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 …
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 …
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 …
... golden rule - "Thou shall test voltages". Seems to me that you ... TR4 is fine. Since the voltages are slightly low, I'd ... your work and then retest voltages. At this stage, you should ... you don't get the voltages you expect. Assuming voltage levels ...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 …
Once you've removed the RAM, power it on and check that all three power supply voltages are present at the appropriate PCB pads. If they are, it'll be fine to fit working 4116s.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 …
... that all three power supply voltages are present at the appropriate ...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 …
... golden rule - "Thou shall test voltages". Seems to me that you ... your work and then retest voltages. At this stage, you should ... you don't get the voltages you expect. Assuming voltage levels ... the lower ram, check the voltages, fit sockets and report back ...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 …
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Anyway, I measured the voltages and now get +4.95 ...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 …
Ok, I'll find and do some checks over the diodes. I am assuming that I don't need to [I]improve[/I] over the board issue's original voltages if I am not attaching any peripherials.
Thanks Mark, Mr. 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 …
... the board issue's original voltages if I am not attaching ...Spectrum Issue 2 - TR6 ReplacementI've just got my hands on an Issue 2 ZX Spectrum, that needed some repairs. The picture quality after doing a composite modification was pretty shodd…
... been molded differently to accommodate TR6 being there.
So ... be a suitable replacement for TR6?Spectrum Issue 2 - TR6 ReplacementI've just got my hands on an Issue 2 ZX Spectrum, that needed some repairs. The picture quality after doing a composite modification was pretty shodd…
... in the ULA is incomplete. TR6 improves the decoding so that ... as "the spider".
TR6 can be replaced with any ... Z80. Some Spectrum boards have TR6 mounted in other locations.
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 -…
... the -5v and 12v supply voltages that these chips need.
voltages are on pins 1, 8 ...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 -…
... ? Are all three power supply voltages present at the lower RAM ...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 -…
Rule #1 - thou shall test voltages
As Zorn Said, ... check you have the voltages needed to run the lower ... of further damage. If those voltages are present the power supply ...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 -…
... . I will also check the voltages on the sockets. Currently don ...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_…
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#1 - Thou shall test voltages
You know the ... 4116 RAM chips need three voltages. These are obtained from the ... based around TR4. Test your voltages - if they are wring, or ...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_…
You need to test voltages on pins 1,8 and ...
