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48k spectrum problems at bootHey guys so my 48k Specfy, Issue 3B is having some issues. They're not entirely consistent but the majority of the time (95%) it presents itself as m…
... having some issues. They're not entirely consistent but the majority ... -80 is faulty or the upper RAM is faulty. Please help!!
+3 memory repair- which ICHi there, I'm trying to repair an old +3 and have bought a Retroleum SMART card. The diagnostic rom test says that the upper ram is faulty and give…
... rom test says that the upper ram is faulty and gives the ... $F0
Unfortunately I've not learnt enough yet to know ... the last address in the upper ram. I therefore don't know ...48k Issue 6a Very sick indeed.Hi Guys. I have a 48k Issue 6a board that shows a white screen with grey border. The white screen has three black squares spaced equally on the le…
... 7805 regulator, socketed lower and upper RAM, switched ram from another board, without ... sloppily, it may be something not quite right there? Also, the ... /> My lower RAM voltages are -5V = -029.5mV ( and not stable, dropping ...Building a ZX Spectrum and I have some voltage questionsI've posted about this before looking for parts, but now I've found all the hard-to-get stuff (thank you Retrolium!). So I figured new questions, new…
... ": +4.82V (probably not important since I'm not installing an RF ... Modulator)
+5V to Lower RAM: +4 ... .98V
+12V to Lower RAM: +12.56V
-5V to ... Lower RAM: -4.31V
+5V to Upper RAM: +4.98V ...OopsToday is a sad day :confused: Poor old rubber keys has gone t**s up. :( All i get is a black screen with a white border. Any body got any ideas …
... 16k), faulty ULA, faulty upper RAM (4532 32k) and faulty CPU.< ... and white border which does not change is most likely a ...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 …
... program that writes to screen RAM every bit pattern, and then ... with (!) by one of the upper RAM chips! A quick replacement later ... +2 now: I have suspected ram fault (coloured flashing blocks). I ... and not 65535! So there must be something wrong with ram.
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 …
... /-L) or TI (-3/-4) upper RAM should work? What about jumpers ... should do.
I am not so good at this but ...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 …
... ,
yesterday I installed upper RAM chips (TMS4164-20). When I ... . It looks like it does not work at all. Previously it ... did not work on one spectrum and ... now it is not working nowhere (keys 3, e ...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 …
... ,
yesterday I installed upper RAM chips (TMS4164-20). When I ... . It looks like it does not work at all. Previously it ... did not work on one spectrum and ... now it is not working nowhere (keys 3, e ...Method to read byte as binary string rather than dec?Hi all Am fiddling around with the screen buffer and have written a routine to scan the screenbuffer into upper ram and then write it back in upside…
... to scan the screenbuffer into upper ram and then write it back ... for lines of text but not for graphic screens.
First ...Why so many disk systems?Why did the Speccy have so many floppy disk systems like wafadrive, tr-dos, +3disk, and many more? As far as I can see, this did nothing but create …
... designed with both sizes of RAM in mind, so I would ... board to plug in the upper RAM block - instead, the 32K comes ... the main board. This is not true of the issue 2 ...Spectrum RAM Paks...This jogged my memory (excuse the pun!!) : [url]http://cgi.ebay.co.uk/CURRAH-32K-RAM-PACK-BOXED-SINCLAIR-ZX-SPECTRUM_W0QQitemZ150057889352QQihZ005QQ…
... that plugging in a 16K Ram pack into a 48K speccy ... ) and the software not realizing that the 16K ram pack is in ... should (theoretically work for the upper RAM also).
Clearly, no ...Nooooo my speccy died!??!!Hi! I am quite sad. :( Tonight I got a kempston interface so I rushed home to try it on my spectrum+ The edge connector of the interface was narrower…
... else. If the voltages are not present, then it's a ... two getting hot - replace these. Not all broken chips will get ... will.
Then check upper RAM, then the Z80 and then ... /74LS32 chips.
Still not working, recheck your work and ...I/O contention model questionHi everyone, Sorry for my poor english. Together with a friend we are working on ZX Spectrum 48k implemented in FPGA. We have found bug in the Spect…
... - why DDR, when 32kbyte static ram ICs are cheap, trivial to ... Spectrum (and thefore the entire upper RAM can be done with a ... normal Zx Spectrum 48k (maybe not as normal, but basic functionality ...Did I killed my Speccy ???Hi guys, 1 minute ago I was working on my 128 +2A... But I made a mistake : I cut the gound on the PSU plug of the computer, and I forgot to resolde…
... four four six four, not four one six four.
NEw RAM chips can be got off ... t just solder in the RAM) and then fit the ... it should be ok - if not, chances are the ULA has ... refuses to initialise a 32K upper RAM block :( Day three at ...Dead Spectrum +Hi all, I've recently dug out my old Spectrum + with the idea of repairing it. When I last looked at it, when I was much younger, I was soldering a …
... to run the RAM. +/- 5V and +12V. If not, check the ... test and replace lower RAM. The RAM can be sort of ...
test and replace the upper RAM. Same procedure - remove, socket, replace ... with known good RAM, test removed RAM.
Test ...Dead Spectrum +Hi all, I've recently dug out my old Spectrum + with the idea of repairing it. When I last looked at it, when I was much younger, I was soldering a …
... chip) that it's not at all heat tolerant otherwise ... solder properly molten, but not so much that the board ... be wrong) first for testing upper RAM, since this will disable ... of RAM and the ULA in cases where they've not ... Speccy, so I'm not sure how realistic I'm ...toasted soeccysHello, ive jsut bought a pair of speccys on ebay (one 16k issue 2 & a prob 48k issue 3) unfortunaly the genius who sold them tried to see if the wor…
... to run the RAM. +/- 5V and +12V. If not, check the ... test and replace lower RAM. The RAM can be sort of tested ...
test and replace the upper RAM. Same procedure - remove, socket, replace ... with known good RAM, test removed RAM.
Test ...toasted soeccysHello, ive jsut bought a pair of speccys on ebay (one 16k issue 2 & a prob 48k issue 3) unfortunaly the genius who sold them tried to see if the wor…
... . Same goes for the upper RAM block too, the hot ... that runs using no RAM. Basically, you just ... to me, means "database" not daughterboard. MB means Megabyte/bit ... not motherboard (I call them ... our own unit conventions - not DIN or ASA, we' ...TV Modulator. Can it be repaired?Is it possible, to repair tha TV modulator (after removing it) if it gives wavy picture? I replaced both transistors (tr1/2) and both electrolytic ca…
... see all the RAM above 32768 - it just will not initialise into ... 16K machine, not 17 or 18K. It initialises RAM all the way ... think) in every location in upper RAM - so it's half initialised ... some reason. It's not bad RAM, it's not bad ROM, it ...TV Modulator. Can it be repaired?Is it possible, to repair tha TV modulator (after removing it) if it gives wavy picture? I replaced both transistors (tr1/2) and both electrolytic ca…
... you overclock your processor and RAM you can do the same ... off
I've not done intensive MC testing, just ... says it's bad upper RAM, but the RAM has not only been changed ... /> The ONLY thing I've not done is fit the sockets ...TV Modulator. Can it be repaired?Is it possible, to repair tha TV modulator (after removing it) if it gives wavy picture? I replaced both transistors (tr1/2) and both electrolytic ca…
... see all the RAM above 32768 - it just will not initialise into ... think) in every location in upper RAM - so it's half initialised ... some reason. It's not bad RAM, it's not bad ROM, it ... in case someone reading does not know, RAM access time is usually ...Whats up wi mi speccy ? M RAMTOP no good 0:3I bought a speccy on ebay tried to load Mission Impossible but about 30 secs into loading it stopped and i got the error message ... M RAMTOP no good…
... up! It works! He's not gonna be a forum member ... fitted, again we have dodgy upper RAM :(
That could be ... line on the Z80, an upper RAM chip has failed at exactly ... - the list goes on, but not very much :)
Do ..."Lost" 48K expansionToday I dug up my Speccy after more than 10yrs of inactivity. I bought it as a 16K in 1983, than I had expanded to 48K and never had problem. Until t…
Assuming the upper RAM is working at all, there ... consists of eight 4116 RAM chips, and upper memory, from 32768 to ... first byte of upper RAM) which indicates either upper RAM is not present at all ... and 8 chips for upper memory - each RAM chip is attached to ...Spectrum ULAHi new to forum ,and have been a speccy owner/fan since the begining{like most 30 somthins on this forum !) Anyway what i want to know is the ULA th…
... tell, if the upper 32K block of RAM and some of ... certainly a problem with the upper RAM. One or more of the ... next ones in line will not be recognised?[/B]
< ... chips with half of it not working - either the high ... the issue 2, why not get them both fixed?Poorly Spectrum + Fault diagnosis help needed!Hi, I've got a Spectrum+. Sometime in the past I broke it and sent it off to be fixed. It came back working good as new, but with an issue 2 board i…
... be honest, you're not likely to miss any of ... and see what happens. Not because the ULA is ...
4) Test upper RAM - sometimes, bad upper RAM just stops working so ... you have, whether or not spare parts are scarce ... or not. There are many ...Alternative chips for upper RAM blockDoes anybody know of a way to use 4464 chips instead of 4164 for the upper RAM block in a 48K machine? If not 4464 then something a little more avai…
... for the upper RAM block in a 48K machine? If not 4464 then ... use 4464s for both upper and lower RAM. The 4464 is a ... 15) and have quadruple redundancy RAM...
If replacing a ...I want to build a new, super spectrum ;-)only kidding Andrew :-) my brain's going at a mile a minute at the moment, so I thought I should put some of the ideas down in case one of them is w…
... chips.
I've not had a "rampack [0] wobble ... couple of pins and may not whack anything critical.
not a ULA replacement, but for ... daughterboards - one for lower RAM, one for upper RAM, which use a modern ...Speccy just snuffed it while playing 3D Pinball :(I have two speccys but the one I use most has just given up the gost! :-( game froze up and now all I get is flashing patterns and lines:-( Everyt…
... . Usually if it's dead upper RAM the Spectrum will still boot ... supply can also kill lower RAM, and it's a really ... chips a while back, if not look up the TMS4116 datasheet ...How to load tzx files into REAL spectrumI have 2 zx spectrum computers, and have been trying to load tzx files into them. I have used several programs to convert them to wav files and them …
... ipod, cd player.
Not 1! There must be a ... , speed loaders *must* load into upper RAM due to timing problems. If ... had a fault in your upper RAM, particularly towards the top end ...
