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Old 24th May 2020, 5:41 pm   #248
Timbucus
Octode
 
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,362
Default Re: Recreating the Bywood Scrumpi

Quote:
Originally Posted by philoupat83 View Post
damage the model will not be able to tell us more i hope nothing serious
i have corrected the latch here is my final plan I transfer on kicad and prepare the gerber for jlpcb I send it Monday
for x I connect it to vcc but with the possibility to cut
Finally we arrive at the end of the recreation. my processor begins to vibrate with impatience
I put the suspected faulty 74LS00 back in and it works again, but still no latch - so I just need to make a test harness to see if just those gates are faulty and I have just been lucky until now - if so I will buy another - well I have already ordered a pack of 10...

My chips (CPU and RAM) is now in Stanstead waiting for customs so it is getting closer to me building a SCRUMPI 1 with a 500 as well - I will make the PSU while I wait...

On the PCB I think you misunderstood me IC12 and IC13 should be totally separate so either can be IN or OUT or both can be the same. So I suggest the following (MR should still be tied to ground)

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