Now the situation is this.
+5V and +12V stable (12V is 11.80, 5V is 5.01)
-5 and -12 were absent under load.
They are generated by two cascaded 7812 and 7905.
The output of the 7812 is fed reversed to output (becoming -12V), and becomes
the input for the 7905, generating the -5V.
If the 7812 is dead, no -12V, no -5V.
I substituted both.
But the 7812, coming from scrapped boards, shouldn't work correctly.
It receives 14V as input, but generates an instable +8V, enough to
drive the 7905. So, now, I have the -5V but not -12, yet.
The 7812 becomes hot again.
I have no spares, so I must suspend.
But I think we're near the end, since only the -12V is missing, and it's not
sensed and generates autonomously.
The input voltage, is stabilized by a capacitor, replaced. 14.5V seems a
correct value, since it should be at least 1.5V above the +12V.
Since it runs hot (and input voltage is correct) I must assume it's not
working...
value



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