[edit] Excuse posting to the wrong forum... Should have gone to the Spectrum Hardware forum [/edit]
Hey all!
On my Issue 3 48k Spectrum ZX I had a Z80 with a bad M1 line. I pulled it and installed a socket and new 10Mhz Z80 (https://www.digikey.ca/en/products/deta ... PEG/929206). Upon power up, the Spectrum did not work. I've checked my work and I have continuity to everything I should, and no shorts that I can find.
Checking the voltages, I discovered that on pin 23B on the expansion port I have +9v. According to the schematics I find online, this should be -12v.
Any ideas what could be causing my issues?
Attached is a photo of the new Z80, and a video of my Spectrums display.
+9v on -12v line? Expansion pin 23B
+9v on -12v line. Expansion pin 23B.
Hey all! Reposting this message to the correct board...
On my Issue 3 48k Spectrum ZX I had a Z80 with a bad M1 line. I pulled it and installed a socket and new 10Mhz Z80 (https://www.digikey.ca/en/products/deta ... PEG/929206). Upon power up, the Spectrum did not work. I've checked my work and I have continuity to everything I should, and no shorts that I can find.
Checking the voltages, I discovered that on pin 23B on the expansion port I have +9v. According to the schematics I find online, this should be -12v.
Any ideas what could be causing my issues?
Attached is a photo of the new Z80, a video of my Spectrums display, and the power schematic that I'm looking at.
On my Issue 3 48k Spectrum ZX I had a Z80 with a bad M1 line. I pulled it and installed a socket and new 10Mhz Z80 (https://www.digikey.ca/en/products/deta ... PEG/929206). Upon power up, the Spectrum did not work. I've checked my work and I have continuity to everything I should, and no shorts that I can find.
Checking the voltages, I discovered that on pin 23B on the expansion port I have +9v. According to the schematics I find online, this should be -12v.
Any ideas what could be causing my issues?
Attached is a photo of the new Z80, a video of my Spectrums display, and the power schematic that I'm looking at.