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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. …
... Is the Speccy gonna work at 7.5V? I guess ... output to about 9.1V at the input of the ... minimum input voltage. The 7805 is not a low voltage drop regulator and ... voltage to function. It is possible that the circuit by Mark at ... 7.5V may be to low in some ... -
Just got a Spectrum +2BThis is the first Spectrum I've ever used or owned. I got it without a video cable or power supply. I wired up a proper video cable, and I altered an…
I'm surprised an AT supply would need a ripple ... keep supplying energy during the low parts of the ripple from ... - line, but if you looked at the output with an oscilloscope ... to by placing an appropriate voltage regulator downstream of the cap (for ... -
old PC with Monocrome Monitor Out.So as discussed in the Carboot sale thread, I have brought and old Apricot Xi. It takes a monochrome monitor via a 9 pin D connector. Now I don't ha…
... *not* TTL level, but some low voltage (and therefore likely analog)? That ... that 12V for a 7805 regulator to power a few 74HCTxx ... .3~0.4V is rather low signal level for analog video ... near impossible. :(
Btw at ?5 that was a good ... -
48k + Spectrum Issue 4S Display IssueHi all! Brand new user here. Growing up I had a zx spectrum for a little bit, and recently I have bought a working 48k + Spectrum (Issue 4). I was…
... and -5.[/QUOTE]The 7805 voltage regulator only produces the +5V supply ... RF modulator box as ground at the moment. Is that right ... the regulator metal tab is connected to ground / 0V.
The voltage ... with the meter on a low voltage ac range.
Hope ... -
Opus Discovery PSU[IMG]http://www.scotek.net/zx spectrum/opus.jpg[/IMG] This is a photo of my Opus Discovery transformer. Can anyone tell me what the connections are …
... know the left side is low voltage and have recorded what goes ... part has been broken off at some time).
... bit more.[/QUOTE]
At the right hand side the ... scorched) at the underside where the rectifiers/diodes and regulator reside, then ... -
Modern PSUHello everyone, I'm looking for a modern PSU for my Spectrums and my dual set of 3.5'' floppy drive+HxC floppy emulator. The one for Spectrum should …
... avoided at all costs. You are unlikely to find a low voltage one ... (usually a linear voltage regulator) to maintain a stable voltage up to its ... more efficiently than a linear voltage regulator. Rather than burning the excess ... -
+3 - beeper sounds but no AY musicHi guys I am repairing a plus 3 revision 2 board that had no sound at all. Using schematics from https://zxnet.co.uk/spectrum/schematics/ I manage…
... the capacitor can hold the voltage at (hopefully nowhere near zero). ... smoothing we have a voltage regulator chip. This uses very ... The amplifier circuits in the voltage regulator then amplify the noise, ... ripple and the regulator noise should be so low, that it ... -
+3 - beeper sounds but no AY musicHi guys I am repairing a plus 3 revision 2 board that had no sound at all. Using schematics from https://zxnet.co.uk/spectrum/schematics/ I manage…
... the capacitor can hold the voltage at (hopefully nowhere near zero). ... smoothing we have a voltage regulator chip. This uses very ... The amplifier circuits in the voltage regulator then amplify the noise, ... ripple and the regulator noise should be so low, that it ... -
Finding a good (UK) external switch mode power supply for the basic 48k and 128k ZX SpectrumsThis idea has probably "done the rounds" by now . I think I have heard about it a bit late . This thread with look at replacing the original "heavy l…
... good quality types, as they at least make an attempt to ... winding is separated from the low voltage secondary winding by being wound ... less than £2.40.
At the same time, it is ... replace the 7805 three terminal voltage regulator with a modern mini DC ... -
PC advice reqd.My monitor/graphic card seems to be acting up! I get strange sort of flicker (similar to the ones you get at slightly low voltage) on the monitor at …
... ones you get at slightly low voltage) on the monitor at seemingly random times ... ) I've been playing FEAR at quite high settings of late ... could also be due to voltage variations but it just doesn ... -
Opus Discovery PSU[IMG]http://www.scotek.net/zx spectrum/opus.jpg[/IMG] This is a photo of my Opus Discovery transformer. Can anyone tell me what the connections are …
... know the left side is low voltage and have recorded what goes ... part has been broken off at some time).
In ... mentioned that it was a low power transformer and would be ... -
Interesting 48K failureI thought I'd recount a failure I've not seen mentioned before that I saw tonight while fixing a 48K issue 6 board. The background: The initial fail…
... only active when A0 is low. When A0 is high, ... Now if IORQGE is held low because it's shorted to ... right value, when A0 goes low it could be that the ... with R27 could mean the voltage at the junction of of R27 ... IORQ pin whenever A0 is low (or especially when A0 is ... -
My own Home Computer It's true. My company are planning to build a new Home Computer. It will use a Z80 CPU running at 6mhz, 128k Ram and will run all Spectrum and ZX81 …
... /> D4 - Parallel port strobe (active low)
F9 - extended ... the VRAM would be at 32k, the bottom at 48k
D5 ... the VRAM would be at 0k, the bottom at 16k
low voltage and small scale chips and ... -
Programming Sound EffectsHi guys, Have decided, probably due in some way to my midlife crisis, to tart up and re-release (or even just re-lease) the old 48K Speccy games I w…
... this means is that very low frequencies are blocked so if ... is an analogue signal -- the voltage at any point in time is ... of the analogue signal's voltage at regular intervals of time. If ... quantize the discrete-time voltage samples. At this point the samples ... -
How Loud Is A SpectrumHi All How loud a Spectrum.. I have yet again bought a third 48k Spectrum that seems to have problems. The machine in question all works but the …
... most peculiar - Steve that looked at the Spectrum in question could ... . Power supplys putting out a low voltage, I have tried two, could ... ouput they could both be low. Cables etc, cannot see it ... -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
7V is too low, you need at least 7V when the transformer ... out voltage at which it'll work properly. 300mA is too low also ... advised you to use a voltage dropping diode, see what he ... -
Mysteries of Electricity QuizA little fun quiz that I know the answers to, but may lead to some head scratching and disbelief, but there's easy experiments than can be performed …
... coiled piece of wire) at DC is a short circuit ... be determined by the voltage at each end of the ... made (which will be very low).
I' ... m hardly an expert at analogue electronics (and quite honestly ... resistance of the same inductor at DC. And I've ... -
spectrum PSU'sI've read contradictory info on which psu(ie amp rating) is for which spectrum. :confused: The models and amp ratings are 1.2A, 1.4, 1.85 and 48k, …
... (not +2a/3) is a voltage regulator, the 7805. It's a ... into a lower, extremely stable voltage, at any current up to an ... inside the Spectrum is another regulator, only this one is a ... special - it converts the incoming voltage to three separate voltages, which ... -
Composite Video output problemHi everyone, I?ve got a problem that?s really bugging me. I have one Spectrum 48K and one Spectrum +3, both with Composite Video output modification…
... +12V at pin 8 of one 4116 chip. If also low voltage, unsolder ... -
Composite Video output problemHi everyone, I?ve got a problem that?s really bugging me. I have one Spectrum 48K and one Spectrum +3, both with Composite Video output modification…
I have 8.24V at pin 8 at a 4116 chip. Both capacitors ... +12V at pin 8 of one 4116 chip. If also low voltage, unsolder ... -
The Goldfinch updates thread([url=http://www.worldofspectrum.org/forums/showthread.php?t=25034]original announcement thread here[/url] - I figured it was worth starting a new to…
... looks" like a very low resistance. This means reset ... be at zero volts. Reset is active LOW for ... the capacitor charges, the voltage at reset out rises. But ...
When the voltage crosses the right threshold for ... IIRC the threshold voltage is quite low, around 1.8 ... -
Can you remote-"fry" a PC?Here's the account of an occurence from a few years ago, something that has been nagging me a little ever since. Back then, I used to hang out in a …
... ..
once at work.. once a woman who ... both were , they changed the voltage at the back of the PC ... coincidence, you would need low level calls to access the ... so it's just happened at the same time..
...
at the moment i'm having ... -
My Spectrum has gone a bit dud since doing some Mods, HELPMy father in law and I did some modifications to my 48K rubber key Spectrum last weekend, and now it seems to be very keen to crash, especially when …
... a 7805 with a switching regulator, often this involves parts ... from damage. With a switching regulator in its place, it' ... "]low-dropout[/URL] regulator, and input a [I]regulated[/I] DC voltage ... that's just high enough (around 6~7V depending on regulator ... -
My Spectrum has gone a bit dud since doing some Mods, HELPMy father in law and I did some modifications to my 48K rubber key Spectrum last weekend, and now it seems to be very keen to crash, especially when …
... /Low_dropout_regulator"]low-dropout[/URL] regulator, and input a [I]regulated[/I] DC voltage ... that's just high enough (around 6~7V depending on regulator ... hard-pressed TR4/5 switching regulator to work a little harder ... -
Spectrum +2a / +3 SCART LeadsEvening all, Over the past week or so I've tried two different Spectrum RGB SCART leads from two different Ebay sellers, on a Spectrum+2A and a Spec…
... serves for high-speed (hence low impedance, low voltage) switching between RGB & ... low-speed, high-impedance (kOhms), and takes up to 12V input voltage ... .. 12V on pin 8 (a voltage lower than 8V is detected ... RGB inputs if the signal at pin 16 is a 1V ... -
128 port hardware patchReading the ULA book has reminded me of something. In The Spectrum Hardware Manual (Adrian Dickens) there is a hardware patch to allow free use of al…
... output will be driven low at the end of the NAND ... up with some intermediate voltage at IORQGE which isn't ... inputs. When both are low, then the output of ... the OR gate will be low. All other conditions will ... When the OR gate outputs low, the transistor is ON, ... -
Getting a ZX Spectrum to work in the USHello all, I'm terribly new to these forums but not to the use of the Spectrum. I have a few in my collection of old machines and one of them I am …
... more common variety. For low current, low voltage DC it really doesn't ... Clive decided to leave it at that. Or 1000 power supplies ... [B]plus[/B] of electrons at the center pin". -
HELP! Problem with USB stickI was restarting the computing this morning when I realized there was a USB stick connected. I removed the stick while restarting and when Windows st…
... lot of PCs leave the low-voltage supply on when they shut ... the PC, then switching off at the wall or pulling the ... -
Which support do you use for loading software?Hi all, It's been a while since i came here... Nevertheless, a question came into my mind... Which support (hardware) do you use for loading into s…
... able to power the output at a high enough level to ... to load into the Speccy at 11000bps from my ipod and ... are definitely there and a low bitrate data file like a ... single AA, AAA or other low-voltage battery then the chances are ... -
Dead Spectrum+Hi! Any suggestions where to start finding what's broken: Spectrum+ with issue 6A motherboard and nothing on TV. Top row of the upper memory chips g…
... to a very low voltage to protect the 7805 regulator, and hence, making ...
