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SPECTRA New from Paul FarrowLooks good! Read about it [URL="http://www.fruitcake.plus.com/Sinclair/Spectrum/Spectra/SpectraInterface.htm"]here[/URL]
... that this thing is using 16K of SRAM to mirror the ... mode that uses more main RAM than the standard screen won ... on a CPLD with external RAM or an FPGA and you ... even bother to set the upper address byte and so there ... -
Spectrum in black TS1500 case with grey "Sinclair ZX Spectrum" labelAt the Spectrum30 event yesterday, someone had brought a Spectrum like object with an unusual case and I never did find out whose it was or where it …
... reason not to release a 16k RAM version lol.[/QUOTE]
upper 32K of the HOME bank ... -
Spectrum in black TS1500 case with grey "Sinclair ZX Spectrum" labelAt the Spectrum30 event yesterday, someone had brought a Spectrum like object with an unusual case and I never did find out whose it was or where it …
... a DCK file where the upper 32K of the HOME bank ... he mentions both the ts2048 (16k) and the ts2068 (48k). He ... mentions the former has 2 RAM chips while the latter is ... -
Spectrum in black TS1500 case with grey "Sinclair ZX Spectrum" labelAt the Spectrum30 event yesterday, someone had brought a Spectrum like object with an unusual case and I never did find out whose it was or where it …
... was supposed to mean 48k RAM; the question was why the ... the 2068 can run with 16k RAM or not -- are you certain ... several new things placed in RAM when compared to the Spectrum ... the main 16k ROM).[/QUOTE]
I removed the upper 32K ... -
Query about memorySo I know this has been asked a lot and I beg your brief indulgence. I have scanned through a lot of old threads already but I'm trying to improve m…
... RAM) chips each 16k addresses by 1 bit wide (the "bottom" 16k of RAM ... indicates that it is a 16k machine.
... matrix has a partial failure but the data line ... 127 for a fully working 16k machine.
... is nonsense for a 16k machine...
Or ... -
Query about memorySo I know this has been asked a lot and I beg your brief indulgence. I have scanned through a lot of old threads already but I'm trying to improve m…
... be also faulty, resulting in 16k version. They were soldered in ... - they could put sockets for upper 32 RAM, making repairs and upgrades ... -
Help me resurrecting a 128KHello to everybody. I'm really struggling along a repair of a standard 128K a friend of mine handed me over some (ok, actually a lot of) time ago. A…
... colors (therefore accesses correctly the RAM bank), then the only possible ... memory locations of the first 16K bank is tested in turn ... 7th 4164 of the uncontended RAM bank, and the test routine ... a write failure of bit 6 and a missing RAM. Any hint ... -
Difference between brands of 4164 chips?I have gotten my hands on a batch of several brands of 4164 chips. Examples are NEC D4164C-3 and Mitsubishi M5K4164ANP-15. Anyone knows if any type …
I received some NEC D4164C-3 from Ben.
I tested them and they work fine as upper (32K) RAM replacements in my Spectrums.
I'll test them as 4116 lower (16K) RAM replacements on my memory adapter pcbs this week and let you know the result. -
+2 grey Contended RAMhi all, i have some quenstions about, contended RAM are banks 1,3,5,7 banks are the pairs of IC's (4164), so 1 pairs = 16k X 4 pairs = 64k this 64…
... about,
contended RAM are banks 1,3,5 ... (4164), so 1 pairs = 16k X 4 pairs = 64k
upper" memory with the same ... />
now psysical, contended RAM are the IC's on ... "64K x 1 Bit Dynamic RAM with Page mode". "The ... -
Issue 3 board... How to resurrect?Dear Everyone, Now I have a working 48k Issue 3, a sort of working Speccy+ (still having problems with the keyboard, more of that in another post) a…
... to get it to 16k by removing the upper 32k and support ... start by taking out the upper memory chips and the support ... all the support TTL and RAM chips in my IC tester ... with the suspect set of RAM chips, it means that one ... -
Which ULA?Just a quick question, more of interest rather than immediate need... I am thinking ahead about the repair of an Issue 2 board, and also an Issue 6A …
... none of the lower RAM chips are heating up ... , the ROM, the RAM combined that process keyboard ... is working (including "lower" 16k DRAM).
What we ... /> Problem with "lower" 16k DRAM?
Problem with ... ]
[*]to disable the "upper" 32K if fitted and try ... -
The Spectrum Resuscitation ThreadKicking off this thread as a place where people who are fixing/restoring Spectrums (or indeed any other piece of related hardware) can show off their…
... .
Removed all lower RAM since it was soldered to ... , although only working as a 16K machine (or maybe even less ... see if I have an upper memory problem also. I shall ... -
ZX Spectrum upper RAM module (4532/4164 replacement)Following the [URL="http://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there have been quite a lot of requests for something similar for th…
... ://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there have ... for something similar for the upper 32K RAM in a Spectrum.[/QUOTE ... is like when both the 16K and 32K replacement modules are ... -
Scrolling by 2 pixelsWhat is the fastest way of scrolling a Spectrum screen line by 2 pixels left or right? When thinking about it I've come to this simple solution: [C…
... keep your program in upper 32K there will be ... you scroll your pixel in upper 32K memory... and if ... upon are in the contended 16K, then it would be ... of fetch/store to those 16K.
In ... store operation on the contended RAM.
Instead, [ ... -
Old homemade hardware?Hey there, I've been given a bunch of ZX Spectrum stuff, I've mostly fixed the computer, just need a membrane. But what I was wondering is that there…
... DRAM fault (either the 16k "lower" RAM) or...
[*]"Upper" (as in the ... BASIC program to test the RAM next.
[I][B ... -
Linking spectrums - parralel processing is it possible?Was there any way to do this, (excluding disk, tape and microdrives)?
... (part of) upper 32K and replace with shared RAM/ROM.
Part ... also be done for the 16K ROM area.
I ... -
Linking spectrums - parralel processing is it possible?Was there any way to do this, (excluding disk, tape and microdrives)?
... (part of) upper 32K and replace with shared RAM/ROM.
Part ... also be done for the 16K ROM area.
I ... , one could use dual-ported ram with some logic to pull ... a fast microcontroller with enough ram and i/o and able ... -
Manic Miner ZX81Hi Guys, Can anyone explain why [url=http://www.worldofspectrum.org/infoseekid.cgi?id=0017539]Manic Miner ZX81[/url] is not able to reproduce the ex…
... -in static 1K RAM only (without a 16K standard RAM expansion) is supposed ... -register and a call to upper memory. This is not different ... -
Issue 3 board with strange piggy-back boardIn case you are interested. I?ve never seen something like this before. I have an Issue 3 board here. When I opened the case and found a strange pig…
... address multiplexers for the 16k. So, they're there ... should, since the lower 16k are not modified in ... address multiplexers for the upper 32k. These shouldn't ... the board was originally 16k, and they only used ... when they installed the RAM sockets. The fact that ... -
Issue 3 board with strange piggy-back boardIn case you are interested. I?ve never seen something like this before. I have an Issue 3 board here. When I opened the case and found a strange pig…
... Spectrum is using to detect RAM (and subsequently set the 23733 ... 32kB fitted but disabled, as 16k Spectrums. Did they just leave ... .8V (which is usually the upper limit that TTL circuits detect ... be confused.
Now, that RAM upgrade *could* require the user ... -
Issue 3 board with strange piggy-back boardIn case you are interested. I?ve never seen something like this before. I have an Issue 3 board here. When I opened the case and found a strange pig…
... removed the chips from upper 32k and I also removed ... should power up as a 16K machine. Unfortunately nothing changed. ... now time to change lower ram.
To be ... speccy powered up as 16k machine when schobi started ... to figure out which Ram chip is broken to ... -
Totally random idea for the hardware nuts to exploreWhen it comes to multi-player games, how hard would it be to generate a second display from a single Speccy, instead of trying to link up machines, s…
... in an entirely separate, pageable 16K bank. It can obviously ... space rather than the 16K ULA/RAM address space? If not ... thinking that writes to the upper 8K of ROM are ... the lower 8K of RAM and accept them into ... its video RAM, at least for a ... -
Spectrum Not Responding to Keyboard InputHello, sorry if this thread is not in the correct place, This is my first post and I'm not sure where to post this type of thread. :lol: Anyway, I r…
... "upper" 32k RAM, because disabling said RAM allows it to start as a 16k ... -
Spectrum screen layoutSeeing the thread on displacement I was wondering why the spectrum had the stupid screen split into three sections and the addresses for each section…
... containing the 16K of contended RAM and an upper half containing ... optional 32K of uncontended RAM. ... address space for contended RAM is only 16K (14 bits) ... kilobit chips for the 16K of contended RAM, with each chip ... -
48K: Half of copyright message in the middle of the screen?!Issue two. Has 74LS08 over the Z80, but the ULA is 5C112E-3 (I think this should be a 5C102E??? - I have one, but I'm not sure if it is working, at l…
... ) that forms part of the "upper" 32k RAM.
If/when ... it is running as a 16k machine.
Of course ... -
Fixing my old ZX Spectrum 48K issue 4AHi Guys, I trying to fix my old Spectrum 48K. Looks like my dad used a wrong power supply as the ULA had a bit missing and so did the 7805. So I rep…
... /CAS signals on each lower RAM chip in turn (pins 4 ... swapped it.
And with upper memory disabled I am back ... to having a booting 16k system showing a white screen ... step is finding the bad upper memory chips :D
Fixing my old ZX Spectrum 48K issue 4AHi Guys, I trying to fix my old Spectrum 48K. Looks like my dad used a wrong power supply as the ULA had a bit missing and so did the 7805. So I rep…
...
(b) for a 16k unit - 32767
I ... answer (b) so running in 16k mode now.
IC ... first byte of the "upper" 32k of RAM returns. [COLOR="Lime"]212 ...Fixing my old ZX Spectrum 48K issue 4AHi Guys, I trying to fix my old Spectrum 48K. Looks like my dad used a wrong power supply as the ULA had a bit missing and so did the 7805. So I rep…
...
(b) for a 16k unit - 32767
I ... first byte of the "upper" 32k of RAM returns. 0
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…
... . Normally the lower 16K is 4116 ram. These two ramchips ... (and limiting the the ram to 32K in the process ... is not connected to the ram at all, as the ... ram if TR4/TR5 blow up.
If the upper ... 32K is also 4164 ram, then this spectrum ...Introduce yourself[SIZE=3][FONT=Comic Sans MS]This is the thread to stop by & introduce yourself.[/FONT][/SIZE]
... Issue 2 48K working as 16K and one Issue 4B with ... a fault in the lower 16k meaning it cannot boot. May ... RAM chips. There's still 1 faulty chip in the upper 32K ...
