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Where do you stick the stack?...OK, so I've got a fair chunk of ASM code assembled from 24000 mark. The stack shouldn't get very big, just a few PUSHes and POPs of the main regis…
... . It's 48K and am not using an interrupt table at ... on, stick it in high RAM especially if there's a ... be tucked away somewhere in lower RAM between bits of code/flags ... -
Where do you stick the stack?...OK, so I've got a fair chunk of ASM code assembled from 24000 mark. The stack shouldn't get very big, just a few PUSHes and POPs of the main regis…
... go high up in RAM (does lower RAM contention affect it a ... ?[/QUOTE]
Not the solution for your question ... systems which need some Ram of the Spectrum. So ... code should be in fast RAM, so higher than 32768 ... . If you need more RAM, use bank switching of ... -
Poorly Issue One 16k spectrum diagnosis?Hello, everyone. :smile: I was lucky enough to buy an Issue One 16k rubber key the other week; I didn't know it was an Issue One till I opened it up…
... chips for Zorn's excellent lower ram replacement module. I get a ... -matching one, but that's not so much of an issue ... pins of the far right RAM chip with a bit of ... -
Poorly Issue One 16k spectrum diagnosis?Hello, everyone. :smile: I was lucky enough to buy an Issue One 16k rubber key the other week; I didn't know it was an Issue One till I opened it up…
... was rated at 50V, not the 63V recommended by Appendix ... unwanted artifacts are in RAM or are being created ... the value of C8 is not critical, as this capacitor ... fault) rather than a RAM fault as the spectrum ... are also stored in the lower RAM.
You ... -
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. …
The lower RAM is in the bottom ... it. The crash may not have anything to do with ... power supply, using a lower voltage alternative would keep the ... degradations and so this may not always be so. They ... failing (possibly killing the lower RAM ICs, depending on which ... -
Pimping an Issue 4SSo theres this 4S I have, its been a pain in the backside for ages, this and that going wrong then I stupidly broke it properly by inserting a keyles…
... again :(
Not happy!
All lower RAM now removed, waiting ... -
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…
... restart.
Removed all lower RAM since it was soldered to ... a few of the elecrolytics, not all, and gave the whole ... -
Strange INK behaviourThis weekend I hooked up two Sinclair ZX Spectrum with Interface 1 to try out the networking capabilities, and I ended up using parts of the Net Game…
... 1 wrote them out, but not in the colors I asked ... ), or an intermittent failure in lower RAM (maybe affecting the system variables ... -
Repairing a torn trace on an Issue 2 PCBI've found what I think could be the reason for my Issue 2 board not working properly... There is a torn PCB trace beneath one end of where a new ULA…
... OP saying he had fitted lower RAM sockets, just one for the ... immediate diagnosis would be a lower RAM fault, assuming his previous work ... say?
Even money lower RAM or ZTX650 based switcher supply ... />
If the OP is not sure of his work, all ... -
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…
... any connected peripherals, but should not be an issue with nothing ... , and that you have working lower RAM, CPU and ROM.
Corrupt paper on zx spectrum 48kHi. When I power up my spectrum (issue 3) I get the light grey border, but the paper is black and it switches between thin red vertical lines and thi…
... two groups of RAM chips.
The so called lower RAM (used for ... the screen so sometimes called the screen RAM ...
The so called upper RAM also uses eight DRAM chips ...
The two types are not interchangeable.
The best ...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…
... :
[LIST]
[*]Program not loading correctly, causing errors which ... DRAM fault (either the 16k "lower" RAM) or...
[*]"Upper" (as in ... BASIC program to test the RAM next.
[I][B ...Replacement Spectrum +3 RAM ChipsHi all Bought a +3 last week with a RAM issue, so I have removed the old chips, added sockets and now just need a full set of chips to get her back…
... +2A, +2B, +3 use dynamic ram 64kx4 chips. The most common ... problem. There is a static ram with sometime use this name ... 41464 chips.If not, look for 4464 dynamic ram chips ( if you ... are bigger then you are seeing static ram)
Bye
First time capacitor replacementHi, I have an Issue 2 board, that i wish to start with recapping as advised on here, as they look to be all original. (Same with V3 board, but going…
... the possibility of replacing the lower Ram with one of his mods ... through it logically, i'm not from electronics background, but am ...Spectrum 48k unstable Colours on Composite Video OutputHi, I?ve an Speccy 48k here which has an Composite Video Out Mod (The Video-Modulators power input is cut from the board). On this I get an unstabl…
... from the ULA accessing the lower RAM, then that's what would ... wrong,
but thats maybe not true. However, with complete dark ...ZXSpectrum intermitent displayHello folks, I've got myself a ZX Spectrum (issue2) with a small display problem and am hoping folks more knowledgeable than myself can help me fix t…
... looks like the TV does not like the video output from ... with the CPU, ROM and "lower" RAM. Also it looks like the ... ), the design of the TV not liking the slightly non-standard ...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…
... a keeper :)
Usual lower RAM defective stripes along with a ... putting the machine back together. Not to worry though, replacement on ...First time capacitor replacementHi, I have an Issue 2 board, that i wish to start with recapping as advised on here, as they look to be all original. (Same with V3 board, but going…
... the typical pattern of a lower RAM failure any more.
RAM area.
You could ... as an alternative if its not throwing out the right volts ...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…
... all voltages on the lower ram and they are all ... 5v available there. (I did not cut any traces :-))
< ... lower Ram did not work was a random pattern of colour blocks. Unfortunately lower Ram ... is without sockets. So what to check next, Ram chips ...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…
... its now time to change lower ram.
To be honest I ... it finally running. I do not want to destroy my own ... have a set of spare lower rams but I guess there ... helpful to figure out which Ram chip is broken to avoid ...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…
... . It has on bank 0 not the diagnostic rom code but ... the lower Ram is broken or the 12V and -5V are not available ... recognized that there is no Ram test using this Rom. Is ... which works and has upper ram and may be address logic ...I've had better nights...So I got a broken issue 2 today, case in good nick but the diags board showing multiple failures in both lower/upper RAM. Never mind, good as a spare…
... Worsley, he suggests testing the lower RAM chips on a resistance meter ... and Ian's seem to not agree with each other regarding ...I've had better nights...So I got a broken issue 2 today, case in good nick but the diags board showing multiple failures in both lower/upper RAM. Never mind, good as a spare…
... get me +3.5v on lower ram, change my lovely ztx 650 ... (I tested and this one not working with divide :( so i ... put message working good, divide not ready, nothing socketed inside nec ...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'…
... generation circuitry (you should be seeing approx. -5v on pin 1 ... failure in one of the lower RAM chips can cause this problem ... /> In the absence of a RAM tester board, your best bet ... to remove all of the lower RAM chips and put sockets in ...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…
... (4 times) to indicate the lower ram failure
- After that all ... me this means that all RAM chips are faulty which is ... and all upper Ram chips
128K Ram test ROM
Or do I totally not understand the output from test ...New CPU and Spectranet oddity.I have no reason to suspect this problem is due to a fault/poor design of the Spectranet, but understanding what it does at system initialisation may…
... me that this question is not new, so I present my ... color blocks (similar to the lower RAM error symptoms).
I ... scope multimeter VC1008.) It did not show any difference in the ... ULA or edge connector did not solved the problem.Born again Speccy user with problemsHello all, Firstly I'd like to say a big hello - this is my first post! When I was 8 or 9 or so my dad bought a ZX Spectrum 48K and a whole bunch o…
... eagerly await your upper and lower RAM modules!
About mono ... measly 0.06 V rms - not the 2.7 V that ... use. I suppose it's not meant to power anything other ... decided to test whether or not the speccy speaker worked during ...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 …
... to one or more faulty lower RAM ICs or failure of their ... its originals; this step may not be essential, but sometimes the ... the lower RAM. If they are present, but the Spectrum is still not ...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 …
... CPU has not been able to fill the RAM, but that ... probably, a non contended RAM chip which could be trashing ... from the CPU to the lower RAM. One of them could ... . The border probably will not be white. Can you ... see colour then? If not, switch off the machine ...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…
... former would indicate a possible lower RAM failure (8 chips at the ... CPU, or in the lower/upper RAM that is holding a data ... like the above when upper RAM is not behaving itself (machine boots ...
