• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

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    Seeking advice on LCII repair: PSU recapped but still grey screen and no chime

    Hi David, Thankyou for the useful information. I had no idea that so much diagnostics were built into these units. Colour me very impressed. I have hooked up a logic analyzer to the serial port but there is no automated data being transmitted by the LCII. I have transmitted 9600bps data @ 5V...
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    Seeking advice on LCII repair: PSU recapped but still grey screen and no chime

    Hi Phipli, I've never actually seen cap leakage firsthand, but I do see the effect it has on the board. I've seen old PCB solder tarnish after years of oxidation and assumed that was the case here. You will see a small red fly-wire connecting the +ve of C19 (47uF) to a via. Unfortunately the...
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    Seeking advice on LCII repair: PSU recapped but still grey screen and no chime

    Hi joshc, I've attached some photos, let me know if there are any important areas you need images of.
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    Seeking advice on LCII repair: PSU recapped but still grey screen and no chime

    Hi David, The OE of each ROM chip (pin24) all have the same 156.68kHz square pulse of 890nS pulse width and Pk-Pk of about 5.32v G1 has a sinusoidal output of 25.17MHz Pk-Pk 1.84v G2 has a much cleaner sinusoidal output of 31.35MHz Pk-Pk 1.76v Y1 has a sinusoidal output of 32.76kHz Pk-Pk 1.0v...
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    Seeking advice on LCII repair: PSU recapped but still grey screen and no chime

    Hi everyone, I have a LCII which I bought on Ebay. Suffice to say the seller used "boots up" instead of "drive makes sounds" and "unit powers up" instead of "unit started once and died". I have recapped the PSU and it works again. I have tested it with a known-good LCIII and there are no issues...
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