PDP 11/24 - A Step Backwards

[Rob Jarratt]

> -----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:
> >> Those three comparators in the H777 are looking at a time-delay ramp
> >
> > Is that a typo? This is the H7140 not the H777.
> 
> 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.
> 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.