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New video about S-video modification on Issue two 48K Spectrum.I just finished an s-video modification on an Issue two 48K Spectrum so I made a video about it. Most of the technical details are in the video; if y…
... not limited to:-
[list][*]Circuit design,
[*]the layout and ... the circuit,
[*]the stability and noise level of the power supply ... bit.
But the circuit design obviously has the biggest ... -
Power supply voltage regulator circuitRelating to [url="https://www.worldofspectrum.org/forums/discussion/56142/"]this topic[/url] I have managed to acquire this little accessory, which I…
... drop (and hence the resulting power dissipation) being handled only ... 700mA, it reduces the power dissipation in the ZX Spectrum ... />
A RCA3055 NPN power transistor is used (rather than ... schematic of a pre-regulator circuit:
[img]https://obrazki ... -
Power supply voltage regulator circuitRelating to [url="https://www.worldofspectrum.org/forums/discussion/56142/"]this topic[/url] I have managed to acquire this little accessory, which I…
... still not sure what the power reservoir is. That lonely capacitor ... the stabilizer part of the circuit just ahead of the bridge ... (4 diodes) found inside the power supply?
Could I ... -
Power supply voltage regulator circuitRelating to [url="https://www.worldofspectrum.org/forums/discussion/56142/"]this topic[/url] I have managed to acquire this little accessory, which I…
... this is a ‘pre-regulator’ circuit.
This is only ... ZX Spectrum, the ‘pre-regulator’ circuit reduces the voltage down to ... schematic of a pre-regulator circuit:
[img]https://obrazki. ... best circuit to be used with an original zx spectrum power supply ... -
Power supply voltage regulator circuitRelating to [url="https://www.worldofspectrum.org/forums/discussion/56142/"]this topic[/url] I have managed to acquire this little accessory, which I…
... it's not short-circuit proof. Not a problem ... a [b]test[/b] circuit. Used to test how ... d call a "minimal application circuit".
Figure 17: If ... for that. Maybe such a circuit was useful once. :-/ But ... circuit to be used with an original zx spectrum power ... -
+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…
... />
First, we transmit power as a AC waveform, with ... , and so supplies the circuit with power. As capacitors are not ... Every time this happens the power supply system has to supply ... br />
Further, the power network will transmit any electrical ... -
+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…
... />
First, we transmit power as a AC waveform, with ... , and so supplies the circuit with power. As capacitors are not ... Every time this happens the power supply system has to supply ... br />
Further, the power network will transmit any electrical ... -
48K Issue 3B slowly fading over 15-20 seconds, capacitor gets hot.Hi folks, Recently my much-modified* RAM testing 48K board failed with a hot/burny smell so I turned it off quickly for looking at later. Thinking…
... of the DC/DC converter circuit that generates the +12V and ... for short circuits (with the power off) and the rail voltages ... -
Special mono tape recorders for Micro owners of the early 1980s So what were the KEY FEATURES of these machines that separated them out from the normal mono tape recorders ? I cannot really remember- but I have …
... keywords here as the integrated circuit took hold and separate components ... actual unit, only in the power brick.
5. Can ... -
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…
... much care for switch mode power supplies. I understand they ... cheap rubbish SMPSU (switch mode power supply units) don’t ... failure. If their internal feedback circuit fails to correctly regulate the ... less current (and therefore less power) from the original ZX ... -
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…
... uses a DC/DC converter circuit to generate a +12V supply ... of the DC/DC converter circuit is essential. It is ... any electrolytic capacitors in their power supply sections.
... warm or hot (diode, power transistor, power resistor, heatsink) then 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…
... slang or marketing names. Power supply unit (PSU), AC ... using various technologies and circuit designs. None of these ... br /> The term “switch mode power supply unit” (SMPSU) refers to ... to manufacture than conventional regulated power supply units.
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…
... the three basic switch mode circuit topologies:-
1) ... com/definition/12378/switched-mode-power-supply-smps"]https://techopedia. ... com/definition/12378/switched-mode-power-supply-smps[/url]
... -48V-AC-to-DC-Power-Adapter-Transformer-30W-240W- ...Gaaaahhhghh! Christmas (Lights)Tis the season to be a grumpy old git. Its now December and as is customary in the USA, after thanks giving the decorations 'must' come out. I've …
... fails and it fails short circuit, the rest will continue working ... that uses a plug-in power supply unit, the electrical clearance ... not. If an electronic control circuit that only switches them on ...Dk'tronics and other similar "add on" Speccy keyboards . What can be done with them and when?. The underlying assumption I am making here is that people who have them will want to "hang on" to them and may also want to get them working . But …
... also noticed that my ZX81 power supply produced rather a high ... them.
16V open circuit on a ZX81 PSU is ... between 13V and 15V open circuit on a ZX Spectrum 1 ...The Complete List Of The Causes Of Lower Ram Failure?Well the aim is to get a comprehensive list.I ask this because I know very little about it . I know that failure of "power supply" related capacitors…
... ,
[*] Damaged due to power supply problems, design limitation of ... expansion being removed while the power is on,
[*] ... the power is on,
[*] Damaged by a short circuit on ... slips and causes a short circuit.
[/list]
...The Complete List Of The Causes Of Lower Ram Failure?Well the aim is to get a comprehensive list.I ask this because I know very little about it . I know that failure of "power supply" related capacitors…
... the last one with the power on .I took that as ... residual voltage left on the circuit after switch off?
power supply and the various leads ...The Disciple clone... doable?Hi. As a spectrum user in the 80's this was the dream interface all-in-one for me. I have a 48k+ and planning on get a 128K toast-rack later. Anyway…
... ? - because of /reset line RC-circuit (1uF and 220KOhm) delay, which ... relatively slow voltage increasing after power-on or reset button press ...Spectrum 128k advice neededHi, I'm new to this forum and the spectrum world. I have this spectrum "toastrack" that was working fine until today. It doesn't boot anymore, it s…
... least 60 seconds, it should power up to the normal start ... . While C27 is out of circuit, test resistor R31 (220kΩ), keep ...zx spectrum 48k low -5volt raili have just received a 48k issue 3. initial tests show that all voltages are there but the -5V rail is only showing -4V. it does boot but i have tur…
... and or a resistor in circuit after the 5.1V Zener ... /> I recommend you upgrade the power supply section of the board ...zx spectrum +2A power supply missing -12v voltshey.. i'm looing at a zx spectrum +2A power supply that the -12v rail seems to be missing .. it has the 12 volts and 5 volts .. it is the version wit…
... have a broken wire in power the cable?[/quote]
circuit as if the diodes are ...zx spectrum +2A power supply missing -12v voltshey.. i'm looing at a zx spectrum +2A power supply that the -12v rail seems to be missing .. it has the 12 volts and 5 volts .. it is the version wit…
... , I’m not sure what power rating it is. The easiest ... /> If the 79L12 goes short circuit or there is a short ... circuit on the output, then the ...Ebay find: Arduitape (virtual tape deck)Hi fellow Spec-Chums I just came across this interesting-looking thingy on ebay and thought i'd share with you guys: [img]http://i.ebayimg.com/imag…
... backlight
3) Amplifier with bypass switch
4)3.5 ... I think) USB connector for power in
THE BENEFITS ...Anybody got a parts list for an Issue 3b please?I've got a schematic, but does anyone have a parts list with the values just for the resistors and capacitors? Just would save me sometime going thro…
... the dc circuit completely and get the 12v from external power supply ...More "What could have been"... The Z280.So in chasing up the Loki specs, I happened upon some parallel developments... And had Sinclair gotten to make the Loki, there could have been some i…
... anticipating from a very simple circuit that was much closer to ... to rivaling the Amiga in power.
Sadly I can ... 've started work on some circuit boards and will morph my ...Were the full Sinclair Loki specs ever actually known?I was just curious. A lot was leaked to the media, but the exact specs seem different depending on source. Some say it could support up to 512x256 an…
... boards.
1. Backplane + Power Reg.
2. CPU 1 ... />
Also, the same video circuit can easily push out all ...Using a thermal camera to fix speccy's.Hi All, Thought I'd share another repair... Got a board that collapsed the bench supply straight away ( I run a bench supply and give it just enou…
... physically disconnect them from the circuit, at which point, you might ... them regardless. Older caps in power supplies really do light up ... they get further from the power supply. It's really noticeable ...I just bought a second hand BBC MasterI have had the notion for a while to get myself a old Beeb - maybe a scrappy one and fix it up - recap its PSU or whatever. Well I gave in yesterday …
... then does that mean the circuit seems to be complete? Is ... why when they fail open circuit the power supply operation is unaffected ...I just bought a second hand BBC MasterI have had the notion for a while to get myself a old Beeb - maybe a scrappy one and fix it up - recap its PSU or whatever. Well I gave in yesterday …
... then does that mean the circuit seems to be complete? Is ... why when they fail open circuit the power supply operation is unaffected ...I just bought a second hand BBC MasterI have had the notion for a while to get myself a old Beeb - maybe a scrappy one and fix it up - recap its PSU or whatever. Well I gave in yesterday …
... is to provide a short circuit path for pulses from the ... and converted back to UK power supplies after they failed to ...
