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Spectrum 48k ProblemsHi all Got my 48k today but it's playing up abit... First time i turn it on it was like this: [IMG]http://s26.postimg.org/hlg9d3f3d/IMG_20140830_…
... copyright message) that it's upper RAM at fault there.
not, if the original caps are ... -
Spectrum 48k ProblemsHi all Got my 48k today but it's playing up abit... First time i turn it on it was like this: [IMG]http://s26.postimg.org/hlg9d3f3d/IMG_20140830_…
... to test it without the upper RAM installed until I also noticed ... stripped down and the TV not being on. You may have ... -
16k to 48K upgradeHi everyone I was just wondering if anybody knows if it is possible to upgrade a 16k Speccy to a 48k with the required RAM chips. If this is possibl…
... 's so simple I'm not sure it'd be necessary ... select which half of the upper RAM is used. Have a look ... the installation instructions for the upper RAM module for a bit more ... you use 4164s or the upper RAM module, a single link should ... -
48K Ram Check Command not workingI am trying to repair my Spectrum 48k. It is having issues loading games, sometimes they load all the way to launch and then the speccy resets. Oth…
... 's another faulty upper RAM IC, so you've not made things worse ... -
48k Stops loading and resetsI've just fixed the problem I had with my Issue 2 Spectrum only showing 16k memory by replacing all of the upper ram. With that job done I've done a …
... an edge case that simple RAM tests won't catch, something ... might not catch this. Without a diagnostic ROM or board, swapping upper RAM ... -
Damaged S2 IC 26?I'm after more advice, pretty please :) On my S2 board there appears to be a damaged chip, it looks to be IC 26 and is marked as 74LS158PC, it appea…
Damaged S2 IC 26?I'm after more advice, pretty please :) On my S2 board there appears to be a damaged chip, it looks to be IC 26 and is marked as 74LS158PC, it appea…
... support OKI upper RAM, which by default the issue 2 does not.[/QUOTE ... ]
What mods were made to make OKI RAM ... i just dropped some OKI RAM into as before it had ...48k Stops loading and resetsI've just fixed the problem I had with my Issue 2 Spectrum only showing 16k memory by replacing all of the upper ram. With that job done I've done a …
... a full set of working upper RAM now though. Took me a ... then if not I'll be sticking an Upper RAM Replacement module in ...48K Ram Check Command not workingI am trying to repair my Spectrum 48k. It is having issues loading games, sometimes they load all the way to launch and then the speccy resets. Oth…
... cartridge which contains a RAM tester program[/URL] can ... a ROM cartridge slot (RAM Turbo etc). [URL="http ... know of) does not need any working RAM to operate, ... of the "lower" or "upper" RAM, as long as the ... not have access to any of the above items, unless a RAM ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
Right, enough moping (not entirely.. been having fun modding ...
[*]8x fried lower ram
[*]8x fried upper ram
[*]Power coil ... has the comp mod, so not too worried about this.
RAM and ULA and testing from ...Weird symptom number 2...I got a new keyboard membrane for my Spectrum+ plugged it in and low and behold the weird left to right printing of the copyright message disappeared…
... />
With regard to the upper RAM theory, thinking about what you ... are correct, the machine has not hung, it's just unable ...Please explain Spectrum FPGA-clones to meI've been using the great ZXDS-emulator on the DS XL so far, which is great. But I kinda missed toying around with hardware. I've tried bidding on a …
... the edge connector.[/QUOTE]
Not so noticeable: at least, signals ... TTL gate, and this is not what the Spectrum design shows ... directly connected to two devices: upper RAM and ROM. The address bus ...Smokin... more 48k woesHi, it looks like I've converted another Spectrum 48K+ into a smoke machine. I'd been rebuilding an Opus Discovery unit and everything looked good. …
... once inserted as there's not enough clearance to stand them ... these headers to provide movable upper RAM selection links, and ROM H ...Smokin... more 48k woesHi, it looks like I've converted another Spectrum 48K+ into a smoke machine. I'd been rebuilding an Opus Discovery unit and everything looked good. …
... once inserted as there's not enough clearance to stand them ... these headers to provide movable upper RAM selection links, and ROM H ...48K Upper memory issues?Having more issues with the 48K spectrum I just fixed that had the black screen in this thread [URL="http://www.worldofspectrum.org/forums/showthread…
... the addresses of the RAM chips are not being properly decoded.
RAM location, hence you getting the ... PEEKed.
Run the RAM test that was linked to ... type of "upper" RAM chips are fitted? Is the "upper" RAM selection link in ...48K Upper memory issues?Having more issues with the 48K spectrum I just fixed that had the black screen in this thread [URL="http://www.worldofspectrum.org/forums/showthread…
... the two channels (stereo) are not exactly the same, and differences ... on some equipment it may not do the output stages any ... use any of the suspect "upper" RAM if the ROM's memory ...48K Upper memory issues?Having more issues with the 48K spectrum I just fixed that had the black screen in this thread [URL="http://www.worldofspectrum.org/forums/showthread…
... have bad upper RAM, you think your lower RAM is fine ... two and you're not convinced the ULA is ... start!
Lower RAM: Since you only THINK it ... when if fact you do not. Test for short circuits ... /> Do the same for the upper RAM.
Then, ...48K Upper memory issues?Having more issues with the 48K spectrum I just fixed that had the black screen in this thread [URL="http://www.worldofspectrum.org/forums/showthread…
I rather suspect the lower RAM test failed because of IC16 ... inter-operate with any other upper RAM types. All eight can also ... the upper RAM module that I sell, but that's probably not the ...Issue 2 Upper Ram, Loading & ResettingI have a 48k Issue 2 Speccy and for the life of me can't track down what the problem is with it. I initially thought that some of the uppe ram ic's w…
I downloaded Zorns RAM tester program a while back ... might be at fault and not the upper RAM. Swapped the ULA over ... Issue 2 and run the ram test program again with the ... swapping and changing a few Upper RAM IC's, run the test ...48K Not booting properlyBought another faulty spectrum from Ebay. This one, when you turn it on, it looks like it's going to boot OK, but when it gets to the point where it…
... a 48K spectrum.[/QUOTE]
Not if it initialised as a ... /> The symptoms strongly suggest an upper RAM fault. If you had forced ... occured, most probably an upper RAM IC is interfering with the ... data bus line at the upper RAM with an oscilloscope often reveals ...48K Not booting properlyBought another faulty spectrum from Ebay. This one, when you turn it on, it looks like it's going to boot OK, but when it gets to the point where it…
[QUOTE=Ricardo99;810958]Could this not be a ULA problem?[/QUOTE]< ... description, I'd suspect the upper RAM in the first instance; it ...Strange keyboard port reads on 48+Hi all, I don't know whether it was already discussed (I also searched forum, but there are too much of results searching "48k keyboard" so I didn't…
... , as the program lies in upper ram (so there must be a15 ... before port is read is not at the beginning of the ...128K RAM tester as .TAP?I was sure that I've seen a RAM tester that can be loaded with e.g. DivIDE or DivMMC EnJOY! as .TAP. But I can't find it (been searching through the …
... from the lower 16K of RAM, so as such it'll ... reliably if lower RAM is good, and upper RAM is not damaged to the ...Finally got round to itFinally got round to giving my old speccy a close look. Details 1982 Issue 2 Seriel No 001 196193 Hmm... Followed the initial tests on You tube w…
... then
Lower ram tested on 200Kohm range
not IC 3 and 4 ?
Upper ram socketed
Test the voltages dude, not the resistance. If you really ... .
Partially socketed RAM sections usually mean the computer ...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…
... for it, solder in lower RAM and ROM sockets, and go ... /Keyboard molex sockets
- Install upper RAM sockets and IC's
not clean enough (I removed a ... excess solder from it, but not all as I ran out ...Dead SpectrumHello guys, I've just bought a dead Speccy 48k (Rubber Keyboard Issue 3 board). Basically, when powered on it initially appears to boot up ok, but in…
... the chips used for the upper RAM.
To really discover ... program (that does not need [i]any[/i] working RAM) running from ... /> *** Note that these devices are not listed in any order, and ... I have tried some, but not all.***
Here is ...Dead SpectrumHello guys, I've just bought a dead Speccy 48k (Rubber Keyboard Issue 3 board). Basically, when powered on it initially appears to boot up ok, but in…
... doesn't always prevent faulty upper RAM from interfering with the computer ... , I've learnt that upper RAM faults are almost as common ... fault is in the upper RAM; the lower RAM is able to receive ... in upper RAM, depending on the nature of the fault, it might not ...Spectrum Ram UpgradeHi, I am looking to upgrade my 16K Spectrum to 48K. I have some 41256 dram chips from an old QL memory expansion, can the Spectrum us the large…
... .
So why not get an upper RAM module http://www.sellmyretro ... .com/offer/details/ZX-Spectrum-upper-RAM-module.-%284532~~4164-alternative.%29 ...64k speccydoes anyone have instructions on how to use the extra 16k found in some spectrums?
... chips used for the "upper" memory are not actually faulty.
... partly working chips. I have not bothered investigating this.
... not have any provision to use any more RAM in the "upper ... chips) of "upper" RAM. If the board does not have fully working ...64k speccydoes anyone have instructions on how to use the extra 16k found in some spectrums?
... you're talking about 32K, not 16 - so I don ... see what I mean. Not often done however since BASIC ... it's on the upper 32K area when you ... :
Bits 0-7 = Not used
- The auxiliary ... chips have been fitted as 'upper RAM'.
Wiring the DRAM ...
