Hi Richard, Could you go into some detail on how your "HV control" signal operates?
carl -------------------------------------------------------- Henry Carl Ott N2RVQ hcarl...@gmail.com On Sat, Nov 23, 2019 at 1:10 AM Kevin A. <ka...@scarletmail.rutgers.edu> wrote: > Glad to hear you're making progress. Interesting that moving the HV psu > away before did not make a difference, but in the new position it did. > Something must have changed with your electrical connections as well which > resulted in that improvement. > > Grounding is crucial to signal integrity no matter the circuit. Keeping > the ground path as short as possible with large, low impedance connections > should definitely improve the situation. > > On Sat, Nov 23, 2019, 12:38 AM Richard Scales <rich...@scalesweb.co.uk> > wrote: > >> I put the 7805 in place but it made no difference whatsoever. I decided >> to change the position of things so that the HV supply was at the 'other >> end' of the clock and the CPU's were at the end where the signal goes to >> the Smart Sockets. There seemed to be some improvement, at one point i >> thought it was completely fixed though staring at the thing periodically I >> could see that it was not not totally 'fixed'. Reading your comment about >> ground wires I will beef-up the 0v and 5v connections to the logic boards >> as they are indeed skinny at the moment. >> >> On Wednesday, 20 November 2019 16:59:26 UTC, Kevin A. wrote: >>> >>> Does it seem like the degree of glitching has been reduced, is the same, >>> or worse with those 2 changes? >>> >>> An LM7805 could support your 5 volt rail depending on how you implement >>> it. The higher the input voltage, the hotter it gets. If you can adjust >>> your buck module to 8 volts, then put the 7805 after the buck module and >>> see if that works. If your buck module will not go up to 8 volts, you could >>> try using the 7805 directly from 12 to 5 volts if you're not pulling more >>> than around 0.75 amps (power dissipation (heat) is increased because of the >>> greater drop from 12 to 5 as opposed to 8 to 5). >>> >>> If that doesn't solve the problem then improving grounding is the next >>> way to go. Ground paths ideally are short and use larger conductors. Having >>> long, narrow ground wires strewn about may certainly be contributing to >>> glitches from noise and undesirable ground loops. >>> >>> On Wed, Nov 20, 2019, 11:35 AM Richard Scales <ric...@scalesweb.co.uk> >>> wrote: >>> >>>> I tried the first two suggestions and thought (initially) that all was >>>> good but upon watching in detail it would seem that it is the same. >>>> >>>> I have a L78M05 to hand - is that going to do the job? >>>> >>>> Otherwise I can get something like this >>>> https://uk.rs-online.com/web/p/low-dropout-voltage-regulators/1246447/ very >>>> quickly. >>>> >>>> >>>> >>>> On Wednesday, 20 November 2019 15:33:20 UTC, Kevin A. wrote: >>>>> >>>>> Here would be my first 2 suggestions in changes to your circuit: >>>>> >>>>> #1: I would definitely place the ground from my logic circuits >>>>> straight to the main power ground, instead of routing it though the 5V >>>>> buck >>>>> module. The buck converter is also a switching power supply and this could >>>>> very well be coupling noise through the rest of your circuit, especially >>>>> if >>>>> it is the only ground path for the logic. >>>>> >>>>> #2: If #1 does not fully alleviate the problem, I would try placing an >>>>> electrolytic cap of between 100-470uF on the 5 volt rail close to the >>>>> logic >>>>> circuits. This could help decouple the logic from any noise entering >>>>> through the 5V rail. >>>>> >>>>> Finally, if the above two do not solve the problem, I would use a >>>>> linear regulator after the 5V module to provide a clean 5 volts to your >>>>> logic circuits. It looks like the 5V module has a trim pot on it, so I >>>>> would increase the voltage to 6 or 7, and then use a 5 volt LDO (low >>>>> dropout regulator) to provide the final 5 volts. This certainly will >>>>> alleviate a large amount of noise on this line that you might not even be >>>>> able to observe on your scope, unless you zoom in quite a bit on the >>>>> vertical (voltage) scale (so that you're looking at hundreds or even tens >>>>> of millivolts per division). >>>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "neonixie-l" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to neoni...@googlegroups.com. >>>> To view this discussion on the web, visit >>>> https://groups.google.com/d/msgid/neonixie-l/7e183735-7ca9-4287-8cc8-51e22a65d43f%40googlegroups.com >>>> <https://groups.google.com/d/msgid/neonixie-l/7e183735-7ca9-4287-8cc8-51e22a65d43f%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "neonixie-l" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to neonixie-l+unsubscr...@googlegroups.com. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/c427b9f9-a8f4-4acb-994b-345063756793%40googlegroups.com >> <https://groups.google.com/d/msgid/neonixie-l/c427b9f9-a8f4-4acb-994b-345063756793%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to neonixie-l+unsubscr...@googlegroups.com. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/CALcVLKJFD_7d4USGx-A-Tjm%2B5mDLO3Ad%3DnbmR6JW6r9S4wpMYg%40mail.gmail.com > <https://groups.google.com/d/msgid/neonixie-l/CALcVLKJFD_7d4USGx-A-Tjm%2B5mDLO3Ad%3DnbmR6JW6r9S4wpMYg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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