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...
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...
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...
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...