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Third-party ZX81 RAM packsOne of the things that's previously held me back from fishing for a ZX81 on eBay - other than "will the ULA on this machine sold as 'untested' be com…
... getting hold of a 16K RAM pack. Now, even back in ... of the existence of other RAM packs that weren't the ... (at least try to) eliminate RAM pack wobble, but then there ... time it had a working RAM pack I was [i]five ... -
MGT Sam Coupe BIG JOBLOT!!! 22 Disks, 3 manuals, 1MB Ram Expansion + Midi Cable!Direclty from my personal Sinclair collection that never end... ...MGT Sam Coupe BIG JOBLOT!!! 22 Disks, 3 manuals, 1MB Ram Expansion + Midi Cable…
Direclty from my personal Sinclair collection that never end...
...MGT Sam Coupe BIG JOBLOT!!! 22 Disks, 3 manuals, 1MB Ram Expansion + Midi Cable!
https://www.ebay.co.uk/itm/173022113295
Have a nice bid ;) -
Testing ram memory of DivIDE / DivMMCHere is new utility for testing DivXXX ram memory: [url="http://velesoft.speccy.cz/zx/divide/software/divramka.zip"]velesoft.speccy.cz/zx/divide/sof…
Here is new utility for testing DivXXX ram memory:
[url="http://velesoft.speccy.cz/zx/divide/software/divramka.zip"]velesoft.speccy.cz/zx/divide/software/divramka.zip[/url] -
Character wobbleHello, I have an Issue 2 board which shows vertical character wobble. This happens for a few minutes followed by a few minutes of character sta…
... fail (taking out the lower RAM) and also causing the 12V ... a possibility that the excess voltage may have
damaged the ... 're pretty robust and the voltage
wasn't that much ... -
sam coupe with external 1mb ramvelesofts site has snaper disks: https://velesoft.speccy.cz/sam_zx128.htm when you use masterdos to detect the external 1mb of ram interface th…
... detect the external 1mb of ram interface then the snaper emulator ... lets you select the fast ram and the zx spectrum game ... uses this ram above 32768 this gives you ... -
Sinclair 16k Ram pAck Issue3 schematicsHi guys, I am willing to repair a 16k ram pack for the ZX81 but I cannot find any schematic of the ISSUE 3 ram pack. I could only find a schematic…
... willing to repair a 16k ram pack for the ZX81 but ... schematic of the ISSUE 3 ram pack. I could only find ... and replace them with 8118 ram which requires only +5V. Problem ... desoldering one of the 4116 ram, I lifted the tiny little ... -
Replacing voltage regulators - need to sanity check a few things pleaseHi Everyone I'm in the process (with a lot of help from some friends at Greenford Computer Club), of giving my three Speccys some much needed prev…
... + upgrade kits)
[b]Voltage regulators:[/b]
I known ... is a 78S05 5v 2a voltage regulator in the +2, and ... -
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…
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It acts as a voltage regulator undoubtedly but I am ... -
48K Issue 2 RAM issuesI have 48K issue 2 board (I've checked, the upper memory is present!). It's not very well. I've not attempted to diagnose one before, so please bear …
... are only in the upper RAM as it will actually boot ... -
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…
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 can do this . But I suspect there are loads of other ways to damage lower RAM ICs? Any ideas? -
zx spectrum +2 cpu questionanother +2 mystery ... so just testing a +2 Z70700 issue 1.. although my power set up was a bit delboy .. PS2 power brick with modified end for the …
... feed via its stand by voltage.. so tested the +2 with ... .. so then i tried the ram diagnostic program by d.smith ... -
upper ram tacks / TR4 socket...[url="https://photos.app.goo.gl/MkqzRCuNCV3EPr9E7"]https://photos.app.goo.gl/MkqzRCuNCV3EPr9E7[/url] you can only replace that pesky TR4 so many t…
... would just fry the lower ram again .. this is one board ... like somebody attacked the upper ram with a black and decker ... sugestions for replacing the upper ram tracks ? -
Quirky nerdy hardware quiz time[b]Quirky nerdy hardware quiz time[/b] [list=1][*]How many transistors are on the issue one ZX Spectrum PCB? [color=#FFFFFF].[/color] [*]Which d…
... tell me the normal forward voltage of a blue one.
RAM chip soldered on to a ... minimum amount of unique (unduplicated) RAM (as seen by the Z80A ... -
zx spectrum display corruption .. with lower ram module installed[img]https://photos.app.goo.gl/Gu6rjC5v21sZxwTX9[/img] [img]https://photos.app.goo.gl/FznVw8SkbbhWn5mh7[/img] another specie question : i have …
... video corruption, it has lower ram module fitted.. can get it ... it shows lower ram as good and upper ram not detected although ... start digging at the upper ram, or the 4 logic chips ... that drive the upper ram.. i am presuming that one ... -
Paging for 64Kb of Video Ram??? What is the best way to page this?Hi all, I'm just putting together a concept card for a "Loki" style of video card, which supports shadow ( so it fits a normal Speccy ) and also t…
... single 48K video page with RAM relocated to the ROM space ... -
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…
... right is the 16 K ram chips. The ULA can be ... power drops below 600mA, the voltage should rise to 9v. )
Voltage/current meterToday I went to my local electronics shop and found this model of voltage and current meter, readily assembled with DC plugs at either ends... :P …
... and found this model of voltage and current meter, readily assembled ...Max RAM for ZX Spectrum gamesHow much RAM can be used for single level/whole game? On tape writing.
How much RAM can be used for single level/whole game?
On tape writing.Original rubber key 48k'sThis question is to some point academic; But i seem to remeber the original 48k Rubber Keys Speccy came in versions 1,2 & 3! (way back when, occasi…
...
in response to sudden voltage fluctuations. This results in the ... +12 volt supplies to the RAM and the appearance of little ...WANTED: tape replacement for +2?Any tape replacement possible for a +2? My +2 works wonderfully but the incorporated datacorder is simply worn out and won't load ANYTHING. Dirty sig…
... and Iss 3 V are voltage levels on pin 28 of ... 6 is 1 if the voltage on pin 28 is over ... with the lower 16K of RAM, and the processor with the ... upper 32K RAM and 16K ROM are working ...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 …
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| ... information on low voltage and small scale ...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 …
... the clock frequency or the voltage across the chip. Eitherway you ... actually SLOWER to access than RAM. Thirdly if you're writing ...Can somebody help me with this?One of my "friends" shoved a piece of metal into the back of my spectrum (48k RAM) and now whenever I try to use it theres nothing but weird lines an…
... an internal voltage converter used by the first 16K RAM bank (+12V ...ZX in FPGA...Hmm..seems nobody is interested in a replacement PCB with FPGA...well..heading towards next FPGA projects then...C64 and others (o; [ This Messag…
... it (ROM, RAM, ULA etc.)...so only needs voltage regulators and config ...Investronica Inves Spectrum +Hi, Has anyone here ever heard of the Investronica Inves Spectrum +? This site [url="http://www.silicium.org/uk/sinclair/inves.htm"]http://www.sili…
... Sinclair range of Spectrums. The RAM was composed by just two ... mapped in that area). The RAM refresh is made by four ... specifically for that purpose. The voltage regulator is placed elsewhere and ... composite. It also lacks the voltage connections -5, +12 and ...Help with dead Spectrum +2aHello. My Spectrum +2a died some time ago. It was powered on, I looked away and next time I looked at it, screen was black. I have replaced the 4 r…
... power sink somewhere, usually a RAM chip, which is lowering the ... a working +2a there is voltage, but on dead one pin ...is my ZX Spectrum + finished :(When i turn it on the screen i get the usual gray border all around but in the screen area i get yellow and some orange lines with a black background…
Yup, one of your RAM chips is shot. Not literally, ... your CPU, ULA, coil and voltage regulators transistors for the -5V ...Want a Speccy Repaired?Maybe it's time to put my 'skills' to use.... Now that I've sourced some of the nastier transistors, I've fixed about 6 rubber keyed Speccys in the …
... 32K are knackered. Check the voltage rail of course - if you ... ground and +5V on the RAM controller chips too.
Want a Speccy Repaired?Maybe it's time to put my 'skills' to use.... Now that I've sourced some of the nastier transistors, I've fixed about 6 rubber keyed Speccys in the …
... 32K are knackered. Check the voltage rail of course - if you ... ground and +5V on the RAM controller chips too.
