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ISR's in lower ram, a.k.a. the snow effect - did any game or demo ever use this?Hi all I've been curious to see what the 'snow effect' looked like in real life for a while now so today I wrote a quick IM 2 ISR in lower ram to wi…
... quick IM 2 ISR in lower ram to witness it firsthand. Pretty ... or similar? I'm certainly not aware of any but then ... -
16K/48K Lower RAM (4116) replacement.You may want to read [URL="http://www.worldofspectrum.org/forums/showthread.php?t=37957"]this thread[/URL] for background information on the quest t…
... SRAM based replacement for the lower RAM that works in all 16K ... levels that appear on the lower RAM address lines. In particular, in ... a 74HC series latch will not work; a 74HCT one will ... this is the ZX Spectrum Lower RAM Replacement Module, pictured below:
help with my original issue 3b from when i was a teen. possible lower ram fault.hello, well ive tried to fix my old speccy, but haven't made much progress. could you help me out with some diagnosis. the fault occurred about…
... * 256 command but it would not complete and the sounder buzzed ... /> is this more likely a lower memory fault? or is my ... certain before I order a lower ram set.Replacing lower RAM 4116 ZX Spectrum 48k - desoldering advice please?A long post, but interesting pictures perhaps. :) I'd like some advice: (also apologies I think I picked the wrong 'Hardware' category for this, plea…
... online seemed to indicate a lower RAM issue. It hadn't been ... the halves of the case (not unexpected). The power supply connector ... solder was applied to the lower side and it had travelled ... />
In the interests of not destroying the board, I've ...zx spectrum display corruption .. with lower ram module installed[img]https://photos.app.goo.gl/Gu6rjC5v21sZxwTX9[/img] [img]https://photos.app.goo.gl/FznVw8SkbbhWn5mh7[/img] another specie question : i have …
... with video corruption, it has lower ram module fitted.. can get it ... and it shows lower ram as good and upper ram not detected although it ... chips that drive the upper ram.. i am presuming that one ... keyboard row 3 was not working- D3 was not making its way ...12V ripple with lower ram installedI repaired a speccy this week. Before doing anything I replaced all caps and measured the transistors in the power section. When doing this I found t…
... Then removed and socketed all lower ram. turned the speccy back ... the scope. Inserted a lower ram module and the speccy was ... Then removed the lower ram module and reinserted all original lower ram ic's ... wasn't there when the lower ram module was inserted.
...zx.zigg.net lower RAM replacement module: Still shipping?Hi everyone I'm trying to resuscitate my 48k issue 6a, and I bought the lower RAM replacement module from zx.zigg.net. The paypal payment went thr…
... 6a, and I bought the lower RAM replacement module from zx.zigg ...The Complete List Of The Causes Of Lower Ram Failure?Well the aim is to get a comprehensive list.I ask this because I know very little about it . I know that failure of "power supply" related capacitors…
Well the aim is to get a comprehensive list.I ask this because I know very little about it . I know that failure of "power supply" related capacitors can do this . But I suspect there are loads of other ways to damage lower RAM ICs? Any ideas?Playing SID Files... :oS SID File player... Anyone else noticed this in the CPC world?... [url]http://www.cpcwiki.eu/index.php/Sid[/url] On that webpage is a CPC program…
... , to make full use of RAM for the 6510 emulation. Though ... it could be adapted to not need lower RAM, there would be a ... in memory at one time. Not a problem with a DivIDE ...Not worth reading really - unless you have some spare time(Mods if you want to move it please do it does have a sort of hardware theme and a couple of recommendations at the end :) About two years ago now I…
... javascript version of ManicMiner and seeing spectrums sell on ebay I ... some soldering time later (Not to metion PaulF re-writing ... had died was the ULA/lower ram, so what would cleaning the ... row "B" to "BreakSpace" was not working... Unsscrewed the IF1, unscrewed ...Difficult to find upper RAM fault.I've recently repaired an issue 3B 48K Spectrum that had a tricky to diagnose upper RAM fault, so I thought I'd post a report of what I found here. …
... code passed from testing lower RAM to upper RAM. Here is an ... is the last byte of lower RAM (32767) being (successfully) tested ... did not decrement a value to zero, the RAM-READ ... not manage to capture the RAM-FILL routine passing from lower RAM to upper RAM ...not working issue 3Hi all, I received this mobo from ebay, after start i have this on screen [img]http://forest.no-ip.org/wos/issue3_01/20150728_135908.jpg[/img] …
... ]
initial tests is not good :) I don't have ... 't have and -5v on lower ram, have only 5v.
I ... i get back 12v but not and this time :) any advices ...ZX Spectrum issue 2 has only blue tintsRecently I've bought a 16k speccy and ran into some issues with it. Faulty keyboard, broken caps, no stable frequency, faulty lower RAM chip, it bein…
... caps, no stable frequency, faulty lower RAM chip, it being 16k, the ... mod (not really fixing it but hey), switched out the lower RAM for ... a modern solution and modern 32k ram upgrade ... as I could gather. However seeing as those chips are nearly ...Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... depopulated , with 4 of the lower ram chips missing , the video modulator ... a label , and one does not. Really these are quite interesting ... and used until they were not needed . But stuff like this ...Lower & upper ram IC's for an issue 3 please.Would any of you great folks have 1 spare lower ram, and 1 spare upper ram IC's you would be willing to sell. I'm fixing up a poorly Spectrum that is…
... have 1 spare lower ram, and 1 spare upper ram IC's you ...divIDE interface not workingA while ago I bought a divIDE interface for my two spectrums (one is a 48k rubber keyboard one, the other is a 48k Spectrum plus). Sadly I never actu…
... , I replaced both upper and lower RAM with a new replacement boards ... already on the memory card). Not to mention some green squares ... it works more often than not. So my guess is that ...upper ram tacks / TR4 socket...[url="https://photos.app.goo.gl/MkqzRCuNCV3EPr9E7"]https://photos.app.goo.gl/MkqzRCuNCV3EPr9E7[/url] you can only replace that pesky TR4 so many t…
... .... surprises me that with TR4 not in place or when it ... it would just fry the lower ram again .. this is one board ... like somebody attacked the upper ram with a black and decker ... sugestions for replacing the upper ram tracks ?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…
... 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 ... something to do with the lower voltages I'm seeing?A thousand core CPU?Maybe this is old news to most people on here, but according to: [url]http://www.zdnet.co.uk/news/emerging-tech/2010/12/25/intel-why-a-1000-core-chi…
... comparing a game with much lower resolution, lower quality textures, and much ... a marginally higher requirement for RAM due to having a general ... a total of 64MB of RAM distributed in any way you ... the morning at work, and not seeing it again until 5:30 ...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…
... 4116 module back in and seeing if the stripey vertical pattern ... the computer is stable or not).
Also, does the ... position if you swap the lower RAM chips around? This might help ... out of spec and is not being refreshed properly.
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 ... +5V is way down, but not zero. It is the typical ...48k not startingHi team, I have 2 48k's, one works (Issue 4s), one doesn't (Issue 4a). The non-working one appears to start, but not finish the RAM test. The pape…
Lower RAM is what I am thinking as well, but seeing as the chips ... an external ROM. I'm not too clued up in this ...Issue 2 problem.Hi all, I'm trying to repair / upgrade an Issue 2 Spectrum for a friend, but have come accros the following problem. When I power the machine …
... .
What you are likely seeing on screen is the wrong ... the lower RAM).
As the lower RAM works when the 32k upper RAM is not ... chips used for the upper RAM upgrade. This looks like something ...Blowtorch method of Speccy repairsI just did my first Spectrum repair (and successful at that). It was the Issue 2 spectrum I wrote about a while ago, I just hadn't got around to doin…
... I suspected either ROM or lower RAM to be bad, since ... thought I'd try the RAM first.
... Spectrums suggests that it is not at all heat tolerant.< ... in all the now empty lower RAM positions, and a socket ... I'm directly soldering the RAM in, in case the ...sinclair zx spectrum issue 6a (again) - how to repairHi All, Is there someone who may explain what these jumpers can be used for. [url]http://forest.no-ip.org/repair/jumpers.gif[/url] <- this is from …
Hi All,
Is there someone who may explain what these jumpers can be used for.
[url]http://forest.no-ip.org/repair/jumpers.gif[/url]issue 6a faultyHi All I got issue 6a pcb from ebay with status faulty pcb had bad voltages when I power up I changed tr4 ztx650 and all voltages got back on ic6 I h…
... got not good sinclair research ltd.
I desoldered all lower ram chips ...issue 4s for reapirHi All, This time I have issue 4s for repair :) Here is few screen shots and small movie after boot. [url]http://forest.no-ip.org/issue4s/[/url] I kn…
... and have good voltages in lower ram
12,5,-5
not i go to standard way, will change lower ram, upper ram, cpu ...4116 ram chipsI need some ram chips to fix my 48k + issue3b, I have done the composite video mod and it works, now i just wanna play games on it but its stuck on r…
I need some ram chips to fix my 48k + ... been advised to replace the lower ram chips. I can't test ...48K Speccy Repair Log.Some people may know my love for writing up my repairs of arcade PCBs on various forums so thought I would do the same for this little fella. Had th…
... ROM sits in the lower 16KB of address space ... blow the entire lower 16K of RAM in one go. ... lower RAM fault, ie something in the 1st 16KB bank but its not ... back as OK, all the lower RAM was fine.
lower RAM and a good CPU, and ...ZX Spectrum Woes...In my endeavours to get my second Spectrum (Issue 3) working I have replaced the CPU, memory and lower ram. I have fitted sockets for the CPU and me…
... replaced the CPU, memory and lower ram. I have fitted sockets for ... the two previously assumed faulty RAM chips.
The only ... major chip that has not been replaced is the ROM ...
