When i power up my Specrrum 48 rev 4B, i get a black screen and white border.
Is this telling something if the ULA and CPU at least is working?
Spectrum black screen with white border
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hellraiseruk
- Dizzy
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- Joined: Thu Oct 07, 2021 6:35 pm
Re: Spectrum black screen with white border
Well, that shows the CPU is working, and for the most part the ULA as well....
JD
JD
Re: Spectrum black screen with white border
You get it every time on power up?
Re: Spectrum black screen with white border
Most faults with spectrums are the lower 16K ram bank.
Most ram bank faults looks similar.
Most repairs begin the same way. Check the voltages to the lower RAM and see if it's -5, 5 and 12v.
After than a diagnostic cartridge is the next step.
Most ram bank faults looks similar.
Most repairs begin the same way. Check the voltages to the lower RAM and see if it's -5, 5 and 12v.
After than a diagnostic cartridge is the next step.
Re: Spectrum black screen with white border
Thnks.
Yes, it comes up everytime with white border and black screen.
Sometimes there is some random color pixels in the black area.
Checked the voltages, and it seems ok: -4.9V, +11.8V, +5.05V
Yes, it comes up everytime with white border and black screen.
Sometimes there is some random color pixels in the black area.
Checked the voltages, and it seems ok: -4.9V, +11.8V, +5.05V