Now why does it not surprise me that reports of a Spectrum not responding to the keyboard (even after a new membrane is fitted) turn out to have defective "upper" DRAM chips :p
! 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 in Somerset later in the year :)
This is why my test ROM displays the ULA inputs at the top of the screen as a character square. As soon as I pressed the Multiface button, I saw the ULA square had two white vertical lines (each horizontal line being a keyboard input line). Sure enough in the RAM test pattern for the upper RAM there was no D3 line at all. Nice and easy. :)
I'm just glad it wasn't the ULA... I only have a few left! Not sure what to do when I run out completely... :/ hope that CPLD / FPGA replacement gets finished soon or I'm going to have to buy the only 10 I know of for sale... for $60 each! Of course I can cannibalize old Spectrums but that kind of defeats the point of using them to repair Spectrums, usually....
Now why does it not surprise me that reports of a Spectrum not responding to the keyboard (even after a new membrane is fitted) turn out to have defective "upper" DRAM chips :p
Although since 4532's are defective by definition, I'm not surprised at all :p
Thanks for sharing the results also - I do like a good repair story :)
The Spectrum Arrived here yesterday, but have had to wait until today to try it out.
I'm Very pleased with the repair and even had the composite modification done at the same time. It certainly makes a difference to the picture quality. :o
Just want to thank everyone for their help in trying to fix the spectrum.:-)
Comments
B
zx-diagnostics - Fixing ZX Spectrums in the 21st Century (wiki)
Sinclair FAQ Wiki
Mark
Repair Guides. Spanish Hardware site.
WoS - can't download? Info here...
former Meulie Spectrum Archive but no longer available :-(
Spectranet: the TNFS directory thread
! 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 in Somerset later in the year :)
I'm just glad it wasn't the ULA... I only have a few left! Not sure what to do when I run out completely... :/ hope that CPLD / FPGA replacement gets finished soon or I'm going to have to buy the only 10 I know of for sale... for $60 each! Of course I can cannibalize old Spectrums but that kind of defeats the point of using them to repair Spectrums, usually....
schombi.de/my-retro-collection.html"
Although since 4532's are defective by definition, I'm not surprised at all :p
Thanks for sharing the results also - I do like a good repair story :)
B
zx-diagnostics - Fixing ZX Spectrums in the 21st Century (wiki)
Sinclair FAQ Wiki
I'm Very pleased with the repair and even had the composite modification done at the same time. It certainly makes a difference to the picture quality. :o
Just want to thank everyone for their help in trying to fix the spectrum.:-)