Papalapa Posted September 28, 2020 Share Posted September 28, 2020 Recently I got an old Acorn Electron that was stored in a loft for many years. Before to turn it on I checked the external transformer voltage and it was correct. I also opened the case and checked the internal power supply disconnected from the motherboard that was also OK, +5v and -5v voltages were present. Then I connected the power supply to the motherboard and once turned on there was not ot a "beep" sound , the keyboard not worked and the light on the keyboard was not illuminated . I only get this image at the composite and RF outputs: I'm aware that the Acorn Electron cannot be turned on with the keyboard disconnected so, I checked the continuity of the flat cable that connects the keboard to the motherboard and all the tracks have had continuity so, it seems to be correct. I measured the voltages at some points as explained in the Service Manual and all of them were correct. Unfortunatelly I don't have oscilloscope and I cannot measure the waveform signals (oscillator, clock, etc...). The only strange think that I detected is that the current compsumation on the -5v is only 3mA while the Service Manual says that should be 25mA. The current compsumation of the +5v is according to the Service Manual. Can be the ULA damaged? What else can I check? Thanks a lot. Quote Link to comment Share on other sites More sharing options...
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