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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 ... -
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 ... the column address to the RAM and so there isn't ... levels that appear on the lower RAM address lines. In particular, in ... this is the ZX Spectrum Lower RAM Replacement Module, pictured below:
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.
...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…
... /> is this more likely a lower memory fault? or is my ... certain before I order a lower ram set.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 ...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 ... solder was applied to the lower side and it had travelled ...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?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 ... start digging at the upper ram, or the 4 logic chips ... that drive the upper ram.. i am presuming that one ...4116 SRAM replacement (and ULA timings).As mentioned in another thread, I have spent quite a lot of time experimenting with different circuits and components for using a static RAM IC to re…
... using a static RAM IC to replace the lower RAM 4116s in a ... installed, CPU access to the lower RAM seems to work perfectly. However ... only suppose that memory access timings for the 5C112E are slightly ... bytes it reads from display RAM.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 ...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 ...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. …
... />
Next, the section RAM-READ begins examining and modifying ... code passed from testing lower RAM to upper RAM. Here is an ... is the last byte of lower RAM (32767) being (successfully) ... capture the RAM-FILL routine passing from lower RAM to upper RAM, but ...ZX Spectrum 48k Issue 2 Faulty Ram?Hi, I have a faulty ZX Spectrum Issue 2 motherboard. Looks in very tidy condition. Though I'm getting random columns of blocks and flashing cursors…
... have read would indicate a lower ram failure. I have lightly touched ... seem cool.
The ram fitted is 8322 4116 2N ...lower ram "new" replacement board.[url]http://www.ebay.co.uk/itm/230994088030[/url] I'm sure others have seen it .. but is it "like for like" compared to the original. .with regard …
[url]http://www.ebay.co.uk/itm/230994088030[/url]
I'm sure others have seen it .. but is it "like for like" compared to the original. .with regard timings etc ?ZX Spectrum upper RAM module (4532/4164 replacement)Following the [URL="http://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there have been quite a lot of requests for something similar for th…
... http://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there ... http://zx.zigg.net/LRR/"]lower RAM replacement module page[/URL] ... the same as for the lower RAM device.
... circuit as the lower RAM replacement and emulates dynamic RAM.
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 …
... that I've seen a RAM tester that can be loaded ... on 128K machines, and if lower RAM works fine, and there is ... a small error in upper RAM.
I have a ...Spectrum 48+ 4S - Upper RAM issue, and now a self-created problem!I recently picked up a known-flaky spectrum off eBay, to have a bit of fun fixing it and reliving youth. It was labelled as 'keyboard duff, shows…
... tape version of Balford's ram test diagnostics said the whole ... of upper RAM was faulty (check all ICs ... 've removed all the upper RAM ICs, replaced with sockets and ... screen.
Given the lower RAM used to be okay, and ...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…
... 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 ?Built a ZX Spectrum that works, but can't get the upper RAM to work?Like the title says I finished my Spectrum 3B board, and it boots, but it doesn't see the upper 32k of RAM. When it boots, the lower 16k works f…
... 32k of RAM.
When it boots, the lower 16k ... even run a RAM diagnostic. Basically, tells me that lower RAM is good ... , all upper RAM bad. But the ... direct connections between the upper RAM and associated logic, and ...Disable onboard memoryWould this work...? Access to onboard I/O can be disabled by holding IORQGE high. Would it be possible to create a MEMRQGE in a similar way to disa…
... ULA controls the lower RAM (including contention by ... the CPU goes for lower RAM at the same ... CAS signal from reaching lower RAM when you want yours ... - and that way, lower RAM will continue to get refreshed ... still comply with memory timings for when /CAS goes ...Spectrum lost upper memoryHi again, I have a Rubber key Spectrum(issue 4S) which lost it's whole upper memory. It's worked okay, but i forgot it on over last night. My son wa…
... the 32k rampack.. has different timings than well normal internal ones ... />
the heat on the lower ram is how a friend said ...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…
... least a few bits in lower RAM are being unreliable.
timings/voltages in the Spectrum+ just ... anyone here aware of any RAM test software for the Spectrum ...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…
... over the display area of RAM and lowering the RAMTOP and ... top half of the lower 16K of RAM.
It ... of the upper 32K of RAM for a while too ... the very top of the lower 3rd of the display area ... for the lower RAM.
Are any of the timings of a ...4116 SRAM replacement (and ULA timings).As mentioned in another thread, I have spent quite a lot of time experimenting with different circuits and components for using a static RAM IC to re…
... and above. The ULA access timings shouldn't depend on the ... in place CPU writes to lower RAM sometimes get corrupted. I am ...lower ram "new" replacement board.[url]http://www.ebay.co.uk/itm/230994088030[/url] I'm sure others have seen it .. but is it "like for like" compared to the original. .with regard …
System timings are decided by the ULA/ ... an SRAM replacement for the lower RAM. It couldn't even interfere ... detect data corruption as the lower RAM is refreshed by the ULA ...What are the differences between the +2 and the +2A ?I only acquired a +2 for the first time in my life a few months ago. It works fine. :) I even managed to tracke down nearly all the wargames by the s…
... . This changed the timings slightly. The extra RAM was added as two ... . One set replaced the 4116 "lower" RAM which includes the scree, so ... set replaced the 32k "upper" RAM chips, which is of course ...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 my ... thought I'd try the RAM first.
I ... in all the now empty lower RAM positions, and a socket for ... I'm directly soldering the RAM in, in case the ... in for the full 48K RAM, and it still worked.< ...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]48K specs boots, but THEN blinking blocks!Of all ZX problems I have seen, the 'blinking blocks' is the most common... Today I picked up a 48K, it boots and THEN it locks filling the screen wi…
... . That is weird... When the lower RAM i broken, it will never ...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…
... ltd.
I desoldered all lower ram chips and put new ... no ...
