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Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
... employed would diagnose that any upper RAM might be bad... isn't ... yet have to test all upper rams to know which is ... -
Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
... the operation of the upper 32K of RAM and so the Spectrum ... one or more of the upper RAM ICs, IC15 - IC22. These can ... thorough (but far from perfect) RAM test program you could try ... -
Query about memorySo I know this has been asked a lot and I beg your brief indulgence. I have scanned through a lot of old threads already but I'm trying to improve m…
... to determine how much RAM is in the Spectrum. ... highest functioning byte of RAM found. To view this ... are also possible when faulty RAM is encountered.
upper RAM ICs (IC15-IC22), ... possibly with some of the upper memory support logic (IC23 ... -
Query about memorySo I know this has been asked a lot and I beg your brief indulgence. I have scanned through a lot of old threads already but I'm trying to improve m…
... to determine how much RAM is in the Spectrum. ... highest functioning byte of RAM found. To view this ... are also possible when faulty RAM is encountered.
upper RAM ICs (IC15-IC22), ... possibly with some of the upper memory support logic (IC23 ... -
Query about memorySo I know this has been asked a lot and I beg your brief indulgence. I have scanned through a lot of old threads already but I'm trying to improve m…
... a 48K model without its upper RAM. A value of 128 (or ... test got part way into upper RAM before it found a non ... -
Query about memorySo I know this has been asked a lot and I beg your brief indulgence. I have scanned through a lot of old threads already but I'm trying to improve m…
... a 48K model without its upper RAM. A value of 128 (or ... test got part way into upper RAM before it found a non ... -
Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
... to check is on 4116 RAM IC's in lower left ... ; shows image (which needs lower RAM + video encoder to work), but ... more RAM software tests to determine if/where what upper memory chip ... SRAM in place of the upper RAM.
Watch ESD precautions ... -
Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
... can test either all of upper RAM or just a small area ... of lower RAM. It stripes a random sequence ... most of the common Spectrum RAM faults. -
Spectrum 16K Issue 3Hi! I just received a Spectrum 16K, which turns out to be an Issue 3. Is it really that rare? If not, I?d like to upgrade it to 48K. There are 12 em…
... a random value in the upper 32K (say 60000) and PEEK ... (from 0 to 255) to upper RAM in consecutive addresses, then read ... ? :) ) - modify values in upper RAM and see if other RAM addresses change when ... -
Spectrum 16K Issue 3Hi! I just received a Spectrum 16K, which turns out to be an Issue 3. Is it really that rare? If not, I?d like to upgrade it to 48K. There are 12 em…
... a random value in the upper 32K (say 60000) and PEEK ... (from 0 to 255) to upper RAM in consecutive addresses, then read ... ? :) ) - modify values in upper RAM and see if other RAM addresses change when ... -
My 48K Speccy has died.Hi fellow WoSer's! Wondering if you could help me with my rubber key 48k Spectrum, which died on me this afternoon. It is one I prevoiusly fixed up j…
... behaviour caused by bad ram. Find a RAM tester written in z80 ... was able to diagnose the upper ram of mine in this way ... turn out to be bad ram, speak to Ian from Mutant ... -
Some stupid 16K questions...Starting with... 1. Should a 16K Spectrum that's been upgraded to 48K behave [I]exactly[/I] like a 48K Spectrum? i.e. should the machine test/clear…
Most likely a faulty 48K. You should test address 32768 with all binary bit patterns. Poking and Peeking numbers 85 and 170 might be sufficient.
A dead (upper) RAM chip often is significant warmer as his colleagues. -
Some stupid 16K questions...Starting with... 1. Should a 16K Spectrum that's been upgraded to 48K behave [I]exactly[/I] like a 48K Spectrum? i.e. should the machine test/clear…
... Spectrum 48k boards with faulty upper RAM have been sold as 16k ... -
Some stupid 16K questions...Starting with... 1. Should a 16K Spectrum that's been upgraded to 48K behave [I]exactly[/I] like a 48K Spectrum? i.e. should the machine test/clear…
It sounds like a fault in the upper RAM.
Try this program: [url]http://www.worldofspectrum.org/forums/showthread.php?p=656549#post656549[/url]
It'll probably let you work out which RAM ICs are faulty. -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
... of a fault in the upper RAM (which is fairly common).
upper RAM, if present is made up ... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
... of a fault in the upper RAM (which is fairly common).[/QUOTE ... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
... . Tell it to test the upper RAM.
The easiest way ... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
... . Tell it to test the upper RAM.
The easiest way ... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
It looks like a 48K Spectrum with an upper RAM fault. Give me a moment and I'll tell you more... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
... suggests that bit 4 in upper RAM is stuck high.
If the present upper RAM ICs are soldered in place ... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
... suggests that bit 4 in upper RAM is stuck high.
If the present upper RAM ICs are soldered in place ... -
16k --> 48kI bought a zx and found out it was a 16k since when I execute PRINT PEEK 23733 I get 127 Does it mean I get a lesser model? What limitations do I h…
TKMEM - the 128K interface for 16K SpectrumsHello all! Here in Brazil, we have made a small production of an interface, totally based on Velesoft?s memory expansion ([url]http://velesoft.speccy…
[QUOTE=Crisis;672363]so now there is beside the 48k upgrade kit a 128k upgrade interface, wow ![/QUOTE]
It's not perfect, but works very well.
And you must disable the 32k upper ram. :DTKMEM - the 128K interface for 16K SpectrumsHello all! Here in Brazil, we have made a small production of an interface, totally based on Velesoft?s memory expansion ([url]http://velesoft.speccy…
... /> [/QUOTE]
The upper 32KB of RAM must be disabled. This ... task for TK90X. If the RAM chips were plugged into sockets ... />
I guess that the upper RAM could be easily disabled in ...TKMEM - the 128K interface for 16K SpectrumsHello all! Here in Brazil, we have made a small production of an interface, totally based on Velesoft?s memory expansion ([url]http://velesoft.speccy…
... /> Some ZX Spectrum boards have upper ram chips in sockets then is ... without sockets must be disable upper ram 32kB (for example via cut ...TKMEM - the 128K interface for 16K SpectrumsHello all! Here in Brazil, we have made a small production of an interface, totally based on Velesoft?s memory expansion ([url]http://velesoft.speccy…
[QUOTE=TK90XFan;674886]The upper 32KB of RAM must be disabled. This is ... task for TK90X. If the RAM chips were plugged into sockets ... ;674886]I guess that the upper RAM could be easily disabled in ... lock the internal 32K of RAM, supply +5V on pin 4B ...TKMEM - the 128K interface for 16K SpectrumsHello all! Here in Brazil, we have made a small production of an interface, totally based on Velesoft?s memory expansion ([url]http://velesoft.speccy…
... can disable the 32k of upper RAM by a wire or jumper ...TKMEM - the 128K interface for 16K SpectrumsHello all! Here in Brazil, we have made a small production of an interface, totally based on Velesoft?s memory expansion ([url]http://velesoft.speccy…
... can disable the 32k of upper RAM by a wire or jumper ...Beta diskJust something that's been bugging me for a while, is the 128k beta disk interface wired differently to the beta 48k as a piece of hardware, or as I …
But could an original Beta Disk interface be used with a 128k machine, for instance allowing a 128k game to be loaded by permitting paging of the upper Ram to occur?The new Superfo cloneHi In the spanish forum speccy.org some guys and me have optimized the superfo clon to have less ICs. The actual design has 39 ICs versus the 45 ICs…
... the Z80 to access the upper ram without collision. But when the ... doesn't need the video ram, the Z80 has unhindered access ... is coupled to the video ram through resistors, in this undecoded ...
