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broken 48K, strange screenwell I finally socketed all lower 16K ram chips, (8 of them in a row near corner, not those 4 in two rows) and replaced them with new ones but it did…
Lower RAM is quite(!) different from upper RAM. -
Spectrum 48k boots but small black dots start appearingAnyone any ideas where I should look first?
... ULA or the start of ram failure. -
Official CSSCGC 2010 Competition ThreadDear Wossers, As 'loser' of the 2009 competition, I am now obliged to host the 2010 competition. I have created a site which will provide a hub for …
... poking a few bytes of upper ram, but still!"
It ... -
Official CSSCGC 2010 Competition ThreadDear Wossers, As 'loser' of the 2009 competition, I am now obliged to host the 2010 competition. I have created a site which will provide a hub for …
... poking a few bytes of upper ram, but still!"
It ... -
Testing 4116 and 4164 chipsI have a stash of old 4116 and 4164 chips and wondered how best to test them to see if they work. I don't have a working spectrum to plug them into …
are 4164 'upper' RAM chips? if so, I'd be interested in buying few of them. -
zx spectrum 48k loading issue (memory problem i think)Hi I have a 48k spectrum that until yesterday was working flawlessly. The spectrum seems to work fine but the problem is with loading games.All the …
... try to identify lower or upper ram and im getting 128, and ... 4, so if it is upper ram then it would be IC19 ... , how to tell if its upper or lower, im missing something ... -
zx spectrum 48k loading issue (memory problem i think)Hi I have a 48k spectrum that until yesterday was working flawlessly. The spectrum seems to work fine but the problem is with loading games.All the …
[QUOTE]Isn't all above 16384 in upper RAM then ?[/QUOTE]
It is. Unfortunately it can be also bad data line. Check PCB, as I remember 3b has soldered DRAM. Otherwise you could just put 4164 chip in socket. -
zx spectrum 48k loading issue (memory problem i think)Hi I have a 48k spectrum that until yesterday was working flawlessly. The spectrum seems to work fine but the problem is with loading games.All the …
Thanks guys, im going to de-solder (what a pain!) and socket IC19 and continue in upper ram until I chase the fault off the board, just needed to know where to start! -
Amperage drastic reduction in a rubber 48KWell, I am now with the approach of a drastic reduction ZXSpectrum amperage. As a first step would change the Z80 processor for other (Z80C). Unfortu…
... FIX
* Rip of Video RAM 4116 and put 4164 doin ... -2084 fix
* Rip of Upper RAM and IC25 & 26 an ... -
ZX Spectrum + alive thanks to this site.I was given a dead unit several months ago. I finally had time to look at it yesterday. Using the repair guide on this site the thing is now alive.…
ZX Spectrum + alive thanks to this site.I was given a dead unit several months ago. I finally had time to look at it yesterday. Using the repair guide on this site the thing is now alive.…
... machine I had with an upper RAM fault, the table on that ... .
What type of RAM chips are on your board ...New game: BozxleHere is a new game called BOZXLE which has been written within a week. The screenshots are of the game running on a 48K. This runs also on the 128 …
... store additional tiles in the upper RAM, you could stored in contended ... RAM a set of tiles for ... copy the appropriate set to upper RAM when starting a game or ...Requesting a little help to identify the purpose of this 'add-on' to my Issue 2Hi everyone First of all it's my first post here so please go easy on me! I'm grateful to be accepted into your fine little club :smile: I probabl…
... the 8 lower RAM chips and the 8 upper ones. The -5v ... it, thereby doing a rudimentary ram test. I assembled it to ... leads me to believe that upper ram is definitely suspect. Unfortunately I ...Requesting a little help to identify the purpose of this 'add-on' to my Issue 2Hi everyone First of all it's my first post here so please go easy on me! I'm grateful to be accepted into your fine little club :smile: I probabl…
... consistently returns the same bad ram address as it did on ... turn out to be bad upper ram?Requesting a little help to identify the purpose of this 'add-on' to my Issue 2Hi everyone First of all it's my first post here so please go easy on me! I'm grateful to be accepted into your fine little club :smile: I probabl…
... turn out to be bad upper ram?[/QUOTE]
From another ... inside - with the lower or upper half in working order, respectively ...Second Hand SpectrumHi just joined the Forum. I have picked up a Spectrum at a s/h shop and would like some advice please. I have had two ZX81's packed away for severa…
... for lower [I]and[/I] upper RAM (details [URL="http://bitcycle.org ...Repairing a faulty 48K issue 2.I am investigating one of a pair of non-working issue 2 48K Spectrums that have been sitting in a cupboard untouched for quite a few years. I haven…
... be fine.
The upper RAM (like the lower) is soldered ...Repairing a faulty 48K issue 2.I am investigating one of a pair of non-working issue 2 48K Spectrums that have been sitting in a cupboard untouched for quite a few years. I haven…
... low going pulses on the upper RAM /CAS (quite why these happen ... written to the top of upper memory, downwards. This is why ... you observe CAS pulses on upper memory.Faulty rubber speccy - advice neededHello all speccy hardware gurus :) Recently I moved to a new flat and after a long time have some space (and time) to dig out my old Speccy hardware…
... found that one of the upper RAM ICs wasn't fitted properly ... values compared to other lower RAM chips, when measuring impedance to ...Rubber 48k troublesHi. I've just got a 48k to add my collection, but it seems doesn't working well. The computer starts ups finely, but it doesn't load the games. So fa…
One of your upper RAM chips almost certainly has a ...Rubber 48k troublesHi. I've just got a 48k to add my collection, but it seems doesn't working well. The computer starts ups finely, but it doesn't load the games. So fa…
... =Spirantho;597771]One of your upper RAM chips almost certainly has a ...Rubber 48k troublesHi. I've just got a 48k to add my collection, but it seems doesn't working well. The computer starts ups finely, but it doesn't load the games. So fa…
The upper RAM is ok. :)
Your machine is a 48K.Rubber 48k troublesHi. I've just got a 48k to add my collection, but it seems doesn't working well. The computer starts ups finely, but it doesn't load the games. So fa…
Testing with 255 is not sufficient, you will not find any bits that are stuck as '1'. Like Spirantho already wrote, you must repeat the test with pokeing (and testing) zeros.
The address 49999 has no significance, upper RAM starts at 32768.Rubber 48k troublesHi. I've just got a 48k to add my collection, but it seems doesn't working well. The computer starts ups finely, but it doesn't load the games. So fa…
... address 49999 has no significance, upper RAM starts at 32768.[/QUOTE]
Repairing another Issue 2 48K Spectrum.I said at the start of the other thread that I've got another one of these and I've started investigating it. The board is more-or-less exactly the …
... Spectrum with its lower RAM removed and so I ... that it would work with RAM installed.
... at all the lower RAM socket pins look reasonable ... problem with the lower RAM, but that something else ... get stuck. Perhaps an upper RAM problem could cause this - ...Spectrum 48K - upper memory MIAI have recently acquired a ZX Spectrum which, according to the sticker on the bottom, should be a 48K model. It's an Issue 3 board, with upper memory…
... a value to all possible RAM addresses. Then, from ... the start of RAM (address 16384) it works ... first address in the upper RAM during this test it ... that go to the upper RAM or one of the ... addresses lines connected to the upper RAM, to see whether RAS ...Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
... you want to remove the upper RAM ICs and they are in ...Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
... you want to remove the upper RAM ICs and they are in ... this Spectrum had a 32K RAM expansion in 1984.ZX Spectrum not working... issue 4S?Hi, I've bought a "new" broken ZX Spectrum +. The idea was to put an harlequin board inside, but for the moment I'm trying to put it in working order…
... get some 4116s?
- Is upper memory more resistant or it ... -5V missing.
The upper RAM needs 5V only and is ...
