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 it not able to drive plain 74xx at all?
>>
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
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 is what kills all
the 7474's?
Ben.
AFAIR LS can only drive one unit TTL load.
I may have some 7474, even of that vintage, if you cannot find any
anywhere else.
cheers,
Nigel
Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
Skype: TILBURY2591
On 2022-05-14 13:48,
> On May 14, 2022, at 1:41 PM, John Robertson via cctalk
> wrote:
>
> On 2022/05/14 10:11 a.m., Rob Jarratt via cctalk wrote:
>> Hello,
>>
>> I have found a bad DEC 7474 chip on my M7133 board. Clearly it is a
>> 7474 D flip flop. The problem is I don't know which modern series
>> would be
On 2022/05/14 10:11 a.m., Rob Jarratt via cctalk wrote:
Hello,
I have found a bad DEC 7474 chip on my M7133 board. Clearly it is a
7474 D flip flop. The problem is I don't know which modern series
would be the best one to replace it with. I am sure I have seen a list
somewhere of modern
Hello,
I have found a bad DEC 7474 chip on my M7133 board. Clearly it is a
7474 D flip flop. The problem is I don't know which modern series
would be the best one to replace it with. I am sure I have seen a list
somewhere of modern equivalents for some DEC chip numbers, but I can't
remember
On Thu, 12 May 2022, Peter Coghlan via cctalk wrote:
> > Wayne: I just got an Dec AlphaStation 200. Look like its running NT
> > though.
> >
>
> It's probably ok but check the power supply for leaky capacitors!
Definitely, watch out for possible damage!
Prompted I had a peek in mine (an
