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ZX Spectrum Microvision - REAL retro setup!Some fun pictures. In reality the picture looks some better and more readible, but the camera doesn't pick it up well. [IMG]http://benophetinternet.…
... the TV by using a 7805 voltage regulator.
And using a battery ... -
Yet another glitchy graphics 48kHeyo, I'm new both to the forums (sorry if this is the wrong forum) and to Spectra I'm afraid, picked up a 48k from a steam fair sale thingy (not th…
... is attached to the 7805 voltage regulator. The 7805 heatsink is electrically connected ... the centre pin of the 7805, which is 0V (also ... this is okay, the 7805 is most likely fine :p ... /58K4KxPY-ws/s1600/7805-pin-gnd-voltage-regulator-5volts-converter.jpg[/ ... -
Plus D Voltage Regulator OrientationHi, I?ve got a Plus D Disc Interface circuit board without case from a friend. Sadly he sends it to me without care for proper packaging. So it arr…
A 7805 voltage regulator has pin out 1,2 ... . You should get a +ve voltage reading. If not, the polarity ... -
Plus D Voltage Regulator OrientationHi, I?ve got a Plus D Disc Interface circuit board without case from a friend. Sadly he sends it to me without care for proper packaging. So it arr…
... when the polarity of the voltage is incorrect.
Just ... 25V electrolytic capacitor and the 7805 voltage regulator should have a 100nF multilayer ... -
Plus D Voltage Regulator OrientationHi, I?ve got a Plus D Disc Interface circuit board without case from a friend. Sadly he sends it to me without care for proper packaging. So it arr…
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- The middle of the voltage regulator was directly connected to the ... 25V electrolytic capacitor and the 7805 voltage regulator should have a 100nF multilayer ... -
Issue 2 crashes after about 30 minsHi Guys, I have an Issue 2 zx spectrum that seems to get graphic corruption after about half hour of playing, then finally falls over and crashes. …
As Zorn says, the 7805 voltage regulator gets hot as it has ... +10V to +11V dc input voltage from the Sinclair "9V" dc ... you do the calculations, the 7805 voltage regulator has to dissipate 4W to ... -
Issue 2 crashes after about 30 minsHi Guys, I have an Issue 2 zx spectrum that seems to get graphic corruption after about half hour of playing, then finally falls over and crashes. …
... will produce a higher voltage output than the rating ... cheap transformers the off load voltage can be around 15% ... from the transformer, so the voltage will "sag" somewhat (amount ... the unregulated input voltage goes to a 7805 voltage regulator chip inside the ... -
Issue 2 crashes after about 30 minsHi Guys, I have an Issue 2 zx spectrum that seems to get graphic corruption after about half hour of playing, then finally falls over and crashes. …
... manufacturers data sheets for the 7805 voltage regulator. They give the drop-out ... voltage as either 2V or 2. ... 5V and the minimum input voltage as either 7V or 7 ... feed this line to a voltage regulator. But I don't think ... -
Plus D Voltage Regulator OrientationHi, I?ve got a Plus D Disc Interface circuit board without case from a friend. Sadly he sends it to me without care for proper packaging. So it arr…
... left hand pin of the 7805 voltage regulator and the centre pin. The ... right hand pin of the 7805 voltage regulator and the centre pin.
Barn Find #1Hi, just back from holiday and found a load of spectrum related bits in my folks old barn. They would probably have been a mates who dumped a load of…
... the heat-sink where the 7805 voltage regulator fits. This ensures a better ...Transistors 101Hi, Im a complete novice when it comes to electronics and would appreciate any help that can be given. Im replacing the transistor that sits on to…
... +12V (or a very low voltage) to the video section will ... voltages, +9V input, +5V (from 7805 voltage regulator), +12V and -5V generated by ...ZX spectrum 128K + 2 (Grey one :)Hi all, I'm trying to revive a dead ZX 128K +2 (the grey one). The regulator was damaged and seemed to be feeding 7.8Volts onto the pcb. Yikes ! I…
... ". It compares this voltage to the voltage on the +5V ... well regulated supply from the 7805 voltage regulator). If TR8 detects that ... is low, the increased voltage difference between the base and ... that in normal operation the voltage *changes* that TR8 sees ...Possible dodgy +2 - resets when loadingSo I have a grey model +2 with a recently refurbed tape deck (new belts and cleaned heads). It might be a product of bad loading, but from what I ca…
... of your meter for voltage testing is either the outside ... the metal tab where the 7805 voltage regulator attaches to the black ... pins together, or with the 7805 voltage regulator, you could short a ... via the tab of the 7805 voltage regulator).
[I][ ...Some problems with 2 ZX Specturm board'sHi, last week i got some ZX Spectrum stuff. Also 2 ZX Spectrum 48K's, one in the orginal case the anoter one in a DK'tronixs case. Both have problem'…
... getting a [B]negative[/B] voltage on this pin or a ... positive voltage?
If you are ... connection.
On the 7805 voltage regulator, connect the black negative lead ... the outside pins of the 7805 voltage regulator chip. One should be + ...Spectrum Missing -5vMy Spectrum is "almost" booting, just when you expect the (C) 1982 Sinclair Research to appear it just displays flashing squares on the screen :( I …
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Is the voltage on the +12V line very ... 9V line (test on the 7805 voltage regulator)? If yes, then it ... good +12V, check the voltage across (between the left ... If you have a good voltage here, either the zener ... or if you get no voltage, as [URL="http://www ...Using a Euro Sinclair PSU in UKI've got a EURO1400 PSU with a Euro plug. Am I right in thinking I can just cut the pug off and change it to a UK plug, and it will work fine? The on…
... problem. Worst case - the output voltage of the PSU may be ... to be dissipated by the 7805 voltage regulator.
It is however possible ... not connected to the Spectrum) voltage will be higher (typically between ...+2 Grey video issueSo far ive replaced TR4, TR5 (and correctly orientated them) and seperated the audio from the video, still I have this; [youtube]mZZWOXRs_Zk[/youtube…
... /> Test on D20 (near the 7805 voltage regulator) cathode (lead nearest the front ...PSU Overvoltage?Going through a pile of 48k PSU's today, rewiring and fitting new plugs, testing each one as I go I came across one that outputs 14.85v, usually im g…
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Normal on load voltage should be between 10.5V ... and sometimes too higher input voltage may cause damage.
... ) can handle a higher input voltage.
The second ... will be released by the 7805 voltage regulator.
[B][I]Mark ...Another "untested" dead spectrum...Hi, I'm looking for some suggestions on a faulty Spectrum I have picked up. I'll need to wait until tomorrow before posting pics, but the screen is …
... I would say that the 7805 voltage regulator is okay, so does not ...Heatsink's for ZX SpectrumAre heatsinks usefull for the chips are used in ZX Spectrum's On eBay I saw some heatsinks for ULA's, 3 for +/- 8 dollar's. And I want to know are th…
... 48k boards:
The 7805 voltage regulator "chip" already has a heatsink ...12v in a Spectrum +2My Speccy 128 +2 requires a 9v 2.1a PSU, all my 9v PSU's are much below 2.1 amps :( I do however have a 12v 2amp PSU, if I reverse the polarity so t…
... correct.
As the 7805 voltage regulator will have to work harder ... (due to the higher input voltage), I suggest you start off ... to test the PSU output voltage when it is actually powering ...12v in a Spectrum +2My Speccy 128 +2 requires a 9v 2.1a PSU, all my 9v PSU's are much below 2.1 amps :( I do however have a 12v 2amp PSU, if I reverse the polarity so t…
... correct.
As the 7805 voltage regulator will have to work harder ... (due to the higher input voltage), I suggest you start off ... to test the PSU output voltage when it is actually powering ...Yellow issue 4A keyboard madnessNote sure if this is a similar problem to the one CornishManicMiner has, but one of my yellow issue 4A boards is driving me crazy. I had it in variou…
... to the tab of the 7805 voltage regulator (where the heatsink attaches), use ... lead of each resistor. The voltage on the other end will ...Spectrum 128 malfunctioning with DIVMMCI recently got myself a spectrum 128 (toastrack) and a DIVMMC card so I could load games from it. It all works fine until it has warmed up and then t…
... to when cold. The voltage drop across a diode reduces ... two biggest sources are the 7805 voltage regulator followed by the ULA. ... better PSU or a pre-regulator circuit. Or a simpler ... remove the heatsink from the 7805 voltage regulator. Clean off any old heatsink ...AAAARRRRR DIV-MMC ENJOY againIve recently been posting trying to get to the bottom of problems with my +48 not working with this rechid addon.Now ive finaly worked out theres not…
... describing is a 3.3V voltage regulator. It reduces the +5V supply ... /48k/plus/128k+ machines the 7805 voltage regulator works so hard, it has ...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…
... /> Test the voltage on pin 1 of the 7805 voltage regulator to test if ... the metal tab of the 7805 voltage regulator as shown by the "0V ...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 …
... can, but apart from the 7805 voltage regulator (that provides the +5V), it ...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…
... , which means that the actual voltage supplied depends on the load ... to kill the Speccy's voltage conversion circuitry.
Personally ... to be dissipated by the 7805 voltage regulator on the ZX81/Spectrum board ...Painting 128+ heatsinkI've searched for this and not come up with anything. Just bought a rather cheap 128+ off eBay which is apparently working (although I haven't teste…
... the heat generated by the 7805 voltage regulator to the air. Heat takes ... prevent the temperature of the 7805 voltage regulator from increasing above the recommended ... unless you change the existing 7805 voltage regulator for a modern switching type ...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_…
... decided to swap out the 7805 voltage regulator for a switching type so ...
