I just received a machine that someone found at a Vancouver second hand
store that I basically told them to buy on the single fact I don't own any
COSMAC machines and I've now had a chance to take it apart and photograph
the boards. It seems to be some sort of a kit system that the previous owner
I have recently acquired a PDP-8/A to go with my PDP-8/E.
Unfortunately it came with the industrial front panel and not the
programmers panel.
Does any one have an extra PDP-8/A programmers panel they can spare?
Also, does any one have any PDP-8/A memory they can spare (or any
Omnibus
I specifically said 74x74. Early TTL flipflops were very crude by
comparison.
On Sun, May 15, 2022, 13:03 Brent Hilpert via cctalk
wrote:
> On 2022-May-15, at 1:16 AM, Eric Smith via cctalk wrote:
> > On Sat, May 14, 2022, 16:09 ben via cctalk
> wrote:
> >> On 2022-05-14 11:50 a.m., Nigel
> You may also want to look at the timing the list software uses for
> deciding when to notify people they've had excessive bounces; I got
> this on April *24*, fully two weeks after I stopped getting messages;
> a similar thing happened on March 21, but that one was only one week
> late:
On Wed, May 11, 2022, 4:06 PM Dave Wade G4UGM via cctalk <
cctalk@classiccmp.org> wrote:
> Jay,
> Thanks for that, I hope its fixed,
> Dave
> G4UGM
>
> > -Original Message-
> > From: cctalk On Behalf Of jwest--- via
> > cctalk
> > Sent: 11 May 2022 13:18
> > To: 'Tom Hunter' ; 'Adrian
> On May 15, 2022, at 2:51 PM, Chris Quayle via cctech
> wrote:
>
> ...
> Original 74 series TTL can still be found, Ebay often, new old stock
> and other surplus vendors.
>
> Would need to take care replacing with later ttl series, as the gate
> delay, switching times and fanout probably
On 2022-May-15, at 1:16 AM, Eric Smith via cctalk wrote:
> On Sat, May 14, 2022, 16:09 ben via cctalk wrote:
>> On 2022-05-14 11:50 a.m., Nigel Johnson Ham via cctalk wrote:
>>> AFAIR LS can only drive one unit TTL load.
paul
>> LS is 4 TTL, 4 ma low.
>> Was there a trick of forcing the
On 05/15/22 18:00, cctech-requ...@classiccmp.org wrote:
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What ever you do, don't use a Fairchild part. When I worked for Intel in
the 80's, we finally band using Fairchild for any latching device. They
failed on pullup current, even when the parts were sent back and they
claimed they were good. We just gave up on them, we couldn't hold
production
Folks,
I probably have some, and now I have found my ICL House Codes sheet I may even
be able to identify them.
However I won't be in the same country as my stock for a couple of weeks.
... and they are in the UK so getting them stateside may take some time.
Dave
G4UGM
> -Original
On 5/15/22 01:16, Eric Smith via cctalk wrote:
> I don't think that worked on any TTL (or CMOS) 74x74 flip flops, except
> maybe by accident if you shorted the output enough to draw Vcc down (or
> ground up) enough to disrupt the FF, and then you have other problems.
Checking my old Moto
On 5/14/22 23:04, ben via cctalk wrote:
> Faster is not better, bigger is bett... ops wrong topic.
>
> 74H while slower, and 74S tend to have reliable delay times looking at
> gates with min to max delays < 3 ns. This helped devices to track
> the same speed across a system.
> A 74ABT00 is 1 to
On Sat, May 14, 2022, 16:09 ben via cctalk wrote:
> On 2022-05-14 11:50 a.m., Nigel Johnson Ham via cctalk wrote:
> > AFAIR LS can only drive one unit TTL load.
> >> paul
> LS is 4 TTL, 4 ma low.
> Was there a trick of forcing the output of D flip flip
> to clear it? I was wondering if this
Those should be fine. Only the more complex parts had issues, not the
simple gates.
On Sun, May 15, 2022, 02:04 Rob Jarratt via cctalk
wrote:
> Oh dear, while I was ordering an original 7474 I ordered some other parts
> that were connected to the same bad chip in case other chips are damaged,
>
Oh dear, while I was ordering an original 7474 I ordered some other parts
that were connected to the same bad chip in case other chips are damaged,
and I ordered a Fairchild 74LS08! I will ask them to change it for a
Motorola part they also have.
> -Original Message-
> From: cctalk On
I'll have to check when I get back from Norway but I believe I replaced thirty
or so flip flops with 74ls74 chips with no problems. This was on my pdp8l and
granted Dec used a lot of 4 and 8 input nand gates to drive loads
On May 15, 2022 12:08:55 AM GMT+02:00, ben via cctalk
wrote:
>On
On 2022-05-14 10:53 p.m., Chuck Guzis via cctalk wrote:
On 5/14/22 15:35, dwight via cctalk wrote:
You are stuck with using an original 7474 family assuming this is driving other
early TTL. 74LS74, and others simply don't have the drive capability to work.
I know LS has less fanout, but is
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