> From: David Clarke
>
> While there certainly would be many possible causes - this
> behaviour can
> also occur because of the 'reset level' adjustment ("DC OK
> Threshhold")
> on the power supply being incorrect (and this setting can change over
> time, as the components in the power supply age).
>
> Specifically, it could be a little low, causing the CPU to wake up
> before it should. If this is the source of the problem, then it is
> something easy to address (and is covered in the Service Manual, ref:
> Section 6 - Adjustments and Checkout)

Or, it could be a little high, causing it to remain held in the reset
state. Although in my experience, the initial LED pattern tends to be more
random when that happens. But you're right, that's always the first thing
to check if you have the old PS board with the three trimmers, because it
is trivial to fix if that's what it turns out to be.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...