one of the problem speccies on my workbench has a "strange" problem ,
i don't know how many specialists tried to repair it , but their traces are everywere.
and the socket too.
Now of course i wonder what can i expect to be defective after discovering this ( and no rotating it does NOT solve any problem ) .
jojo
what goes wrong when you swap the ula position ??
what goes wrong when you swap the ula position ??
Zx81-16k exp.- Spectrum 48 - Spectrum 128- Interface 1 - DIVide - Zx flashcard- Zx printer - Ram turbo-Velleman interface system-Currah microspeech -Ql - 512k exp.- Ql printer - Cst floppy interf.- Double 3.5 floppy- Minerva - Qimi-and much more .
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Re: what goes wrong when you swap the ula position ??
The actual manufacturers that populated the PCBs for Sinclair were not too bothered about getting the IC sockets the correct way round
Normally if you put a chip in the wrong way round, it normally dies very quickly. It is possible, due to the design of a ULA chips, that it may have survived.
Mark
Normally if you put a chip in the wrong way round, it normally dies very quickly. It is possible, due to the design of a ULA chips, that it may have survived.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer being good this year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer being good this year.
Re: what goes wrong when you swap the ula position ??
so i gave her a new ula , and the result now looks like this ;
so i can say that something is working now , albeit with heaps of other problems .
so i can say that something is working now , albeit with heaps of other problems .
Zx81-16k exp.- Spectrum 48 - Spectrum 128- Interface 1 - DIVide - Zx flashcard- Zx printer - Ram turbo-Velleman interface system-Currah microspeech -Ql - 512k exp.- Ql printer - Cst floppy interf.- Double 3.5 floppy- Minerva - Qimi-and much more .
Re: what goes wrong when you swap the ula position ??
Not long ago I saw this...
I just put it back in the right way and all worked fine...
I just put it back in the right way and all worked fine...
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
Re: what goes wrong when you swap the ula position ??
unfortunately my project shows the image above ( after being fully dead , so ula was surely killed )
now to find the solution to get it fully working again
now to find the solution to get it fully working again
Zx81-16k exp.- Spectrum 48 - Spectrum 128- Interface 1 - DIVide - Zx flashcard- Zx printer - Ram turbo-Velleman interface system-Currah microspeech -Ql - 512k exp.- Ql printer - Cst floppy interf.- Double 3.5 floppy- Minerva - Qimi-and much more .