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Fault ZX Spectrum 48k

Posted: Fri Apr 02, 2021 5:46 pm
by Barney5050
Hi went to play this today and have this on start screen , doesn’t get to point where I can get keys to work , any ideas ?

Thanks

Re: Fault ZX Spectrum 48k

Posted: Fri Apr 02, 2021 6:51 pm
by 1024MAK
Hello and welcome :D

I’ve moved this topic into the ZX Spectrum Hardware area.

The good news is that it looks like the Z80, the ROM, the ULA and most of the RAM is working. But after doing it’s memory check and trying to set the system up, the Z80 is crashing. It could be a fault with the upper RAM.

Do you have any test gear, such as a digital multimeter? Logic probe, or oscilloscope?

And are you able to solder?

Mark

Re: Fault ZX Spectrum 48k

Posted: Fri Apr 02, 2021 7:01 pm
by Barney5050
I can solder but have no test equipment unfortunately

Mark

Re: Fault ZX Spectrum 48k

Posted: Fri Apr 02, 2021 8:41 pm
by Tiger
I also think it is a faulty upper-RAM. ;)

Re: Fault ZX Spectrum 48k

Posted: Fri Apr 02, 2021 9:04 pm
by 1024MAK
You could disable the ‘upper’ DRAM. Follow the advice in this post.

Mark

Re: Fault ZX Spectrum 48k

Posted: Sat Apr 03, 2021 12:48 am
by Barney5050
Ok will have a look thanks