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Fixing my old ZX Spectrum 48K issue 4AHi Guys, I trying to fix my old Spectrum 48K. Looks like my dad used a wrong power supply as the ULA had a bit missing and so did the 7805. So I rep…
... loading red green lines , shows program name , the yellow blue lines ... crash but fails to load program.
Other thing is I ... do not hear the program load on the zx speaker ... .
Running the RAM test program I found here I get ... -
X=Y=ZFirst public outing of X=Y=Z for the 48K Spectrum, a 4-level demo which can be download from: [as TZX] [URL="http://www.bobs-stuff.co.uk/extras/xyzd…
... of subtle timing issue, or floating bus issue maybe? -
X=Y=ZFirst public outing of X=Y=Z for the 48K Spectrum, a 4-level demo which can be download from: [as TZX] [URL="http://www.bobs-stuff.co.uk/extras/xyzd…
... 0xFFs.
Probably a floating bus value is sending the code ... -
X=Y=ZFirst public outing of X=Y=Z for the 48K Spectrum, a 4-level demo which can be download from: [as TZX] [URL="http://www.bobs-stuff.co.uk/extras/xyzd…
... of subtle timing issue, or floating bus issue maybe?[/QUOTE]
Doe ... -
Help me fix my grail ZX 128k SpectrumHi all, Ok today my grail toaster rack ZX spectrum 128k turned up. I finally found one and for a reasonable price. I powered it up and..... Nothing …
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Try a simple BASIC test program:
10 LET A ... -
Which Speccy is best?Has anyone done any analysis to suggest which of the various Speccy models is the most technically reliable?
... get a +2B, do the floating bus mode, and install the old ... -
ZX-Modules app reportZX-Modules app report If You are interested, I want to report about the state and progress about my ZX-Modules programs. I would like to report at l…
... this, I wrote a small test program that checks the age by ... -
Interfaces & ROMsHi everyone, I'm currently looking into the various modern interfaces for the Spectrum to allow me to run all my games from an SD card. I have a few…
... will help.The RAM test programs that are available ... to RAM, execute the program in RAM and switch ... map.
Any test program that is a tzx also ... load up one of the test ROMs, correct?
test always available.
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…
... to use the Microhobby RAM test program. It will tell you which ... pause/resume loading, as the test requires you to stop the ... . As you are going to test a 48K machine, input 48 ... (very short)
The test itsef does a series of ...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…
Yeah IC16 was for me. Apologies if I've caused any confusion ;)
I tried the Microhobby RAM test program anyway. Put the TAP file onto tape and gave it a go and it works great. Does indeed show IC16 as being at fault in my case.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 …
... /> I'll try the other test program also, but I have already ...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…
... of variations on using a test ROM.
The ... contains a RAM tester program[/URL] can be used ... at soldering, and can program EPROM or EEPROM chips, ... you can program the chip, then modify ... br />
The ROM test program (there are at least two ...Interface1bis and alternate roms?I was wondering if it's possible to put alternate ROMs on the Interface1bis? I'd like to try using the Gosh Wonderful ROM without having to make any …
... be possible to load a test program (ROM) into the IF1bis so ... Spectrum hardware tests, like the test ROMs. In other words, I ... not want to load a test program from the IF1bis. It must ... the time of building a test interface like the one that ...Interface1bis and alternate roms?I was wondering if it's possible to put alternate ROMs on the Interface1bis? I'd like to try using the Gosh Wonderful ROM without having to make any …
... be possible to load a test program (ROM) into the IF1bis ... hardware tests, like the test ROMs. In other words, ... not want to load a test program from the IF1bis. It ... time of building a test interface like the one ... could be used to test machines that have no ...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 …
... problem: after the diagnostics, the test program says it is paging in ... shows that when the diagnostic program is doing Spectrum ROM CRC ... . But at the end of program, ROM stays disabled. Anyway the ...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 …
... problem: after the diagnostics, the test program says it is paging in ... shows that when the diagnostic program is doing Spectrum ROM CRC ... . But at the end of program, ROM stays disabled. Anyway the ...'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…
... the Z80 and the ROM/floating bus or random data produced by ... noise/the floating bus. So think boarder with the ...'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…
... the Z80 and the ROM/floating bus or random data produced by ... noise/the floating bus. So think boarder with the ...Kempston joystick detectionIn both [url="http://skoolkit.ca/disassemblies/manic_miner/asm/34252.html#34332"]Manic Miner[/url] and [url="http://skoolkit.ca/disassemblies/jet_set…
Aye, floating bus related.
In various ... will return either 255 dec (bus drifted to high) or whatever ... on the ULA / "lower" RAM bus during the screen video data ...Kempston joystick detectionIn both [url="http://skoolkit.ca/disassemblies/manic_miner/asm/34252.html#34332"]Manic Miner[/url] and [url="http://skoolkit.ca/disassemblies/jet_set…
... no idea about the ULA/floating bus thing.
Any idea ...Kempston joystick detectionIn both [url="http://skoolkit.ca/disassemblies/manic_miner/asm/34252.html#34332"]Manic Miner[/url] and [url="http://skoolkit.ca/disassemblies/jet_set…
... no idea about the ULA/floating bus thing.
Any idea ... easily a scanline.
The bus is either going to be ...Kempston joystick detectionIn both [url="http://skoolkit.ca/disassemblies/manic_miner/asm/34252.html#34332"]Manic Miner[/url] and [url="http://skoolkit.ca/disassemblies/jet_set…
... no idea about the ULA/floating bus thing.
Any idea ... easily a scanline.
The bus is either going to be ... they properly buffer the Video bus rather than relying on resistors ...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…
... is only a first, simple test.
I take it ... use a RAM test program. If a tape loaded test does not work ...Correction of +2 hardware errorsThis is a collection of various pieces of information picked up from various places, including a lot from this forum. I have edited it and reworded i…
... read of port 7FFD (write floating bus data)[/QUOTE]
I ...Detecting flash mode inversionsIs is possible to detect with certainty when flashing characters change from normal to inverted and vice-versa?
... it's internals? Like snow? floating bus?Detecting flash mode inversionsIs is possible to detect with certainty when flashing characters change from normal to inverted and vice-versa?
Could you monitor the floating bus to find the point where ... and white then read the floating bus until the attribute reads change ...Detecting flash mode inversionsIs is possible to detect with certainty when flashing characters change from normal to inverted and vice-versa?
[QUOTE=Basher;802628]Could you monitor the floating bus to find the point where the flash switches over then count frames from then on?[/QUOTE]
floating bus behaviour is well examined, I don't think ula wil give up this information easily.Detecting flash mode inversionsIs is possible to detect with certainty when flashing characters change from normal to inverted and vice-versa?
[QUOTE=Arda;802629]floating bus behaviour is well examined, I ... course the value on the bus is coming from memory to ...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…
Run the RAM test program found at [URL="http://zx.zigg.net/zxsoftware/"]http://zx.zigg.net/zxsoftware/[/URL] and post its output here.
