2 Apr
2022
2 Apr
'22
7:12 a.m.
-----Original Message-----
From: Brent Hilpert <bhilpert at shaw.ca>
Sent: 31 March 2022 22:48
To: rob at jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Re: PDP 11/24 - A Step Backwards
On 2022-Mar-31, at 2:14 PM, Rob Jarratt wrote:
Groan.
When this thread came up I went looking for the 11/24 schematic. I found
the document I linked earlier for the 11/24 and found 'the' +5 power
supply.
Those
three comparators in the H777 are looking at a time-delay ramp
Is that a typo? This is the H7140 not the H777. So apparently I've been looking at the wrong +5V
supply (H777) because the
rest of you are indeed looking at a different +5 supply (H7140), both of
which
are in that same 11/24 pdf document.
And indeed, the ACLO control is Q15 in the H7140.
I really wish when people are asking for assistance or talking about a
schematic or circuit they would include a link/reference to exactly what
they
are looking at (a) so the reader doesn't have to
go scratching around to
find it
and (b) to avoid effort-wasting screw-ups like this.
Sorry about the wasted time. I think I did say at one point that it was the
H7140, but that will be way down the thread somewhere. I will use PDF page
numbers in future.
So yes, you can ignore a lot of the details I described, though some of
the
principals I mentioned are still valid.