On Sat, 26 Aug 2017, Dominique Carlier wrote:
I have temporarily replaced the 2N6471 by an approaching equivalent, I makes the settings to get very exactly + 5V on both outputs and the machine restarted, finally! YES !! :-)
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then 02, 03 !! 04 !!! 05 !!!!!! And then ... nothing, and since it got worse, it did not pass the stage 02. Now it crashes from the beginning, nothing on the screen. Is my disk pack damaged? :-/
Please measure the voltages on the boards (like pin 14 of some standard TTL IC). Usually there's a non-negligible voltage drop between the PS output and the logic caused by the inevitable resistance of the connectors. It is entirely possible that the disk controller behaves erratically when powered with e.g. 4.7V instead of 5V.
Christian
