I agree. The blanking is not working and as a result the beam is also faintly visible as it moves quickly between the characters as well drawing the arcs. It would be a good idea to check the BLNK signal on a scope and at least see that is is toggling but my money would be on the analogue blanking section. Given the other side of the optoisolator in the blanking section is at a fairly high negative voltage potential (as this reduces the need for the deflection amps to handle higher voltages) you will need to be careful when probing around there but I would start by checking the voltages across C54 and C55 (as long as you are confident doing so safely with the HV potential to ground). The correct voltages aren't specified on the schematic but they will be based on the grid cutoff voltage of the tube. If you wanted to avoid probing while the clock is on I'd be inclined to shotgun replace that section starting with the power supply diodes, caps and Q13 and then U17 and finally the passives and see how you go.
- Tristan On Tuesday, October 19, 2021 at 4:24:11 PM UTC+10 iavine wrote: > From what I remember: > the characters are generated from circles, ellipses or lines which in turn > are created using sun or cosine waveforms > To make a character the beam is blanked for certain parts eg C is a circle > with a bit cut out. > > Looks like the blanking is not working as you’ve got a lot of circles and > ellipses there. > > Looks cool though > > Cheers > Ian V > > On 19 Oct 2021, at 06:08, Mac Doktor <themac...@gmail.com> wrote: > > > > > On Oct 18, 2021, at 7:53 PM, Gary Kaufman <geka...@gmail.com> wrote: > > I've now got a stable, but scrambled display (see pic's). I think I have > a problem with the shape generators but would appreciate any help or > suggestions you could offer. > > > Nah, that's just Cyrillic Neu Sans. > > > Terry Bowman, KA4HJH > "The Mac Doctor" > > "If only you could see what I've seen with your eyes."—Roy Batty, *Blade > Runner* > > -- > 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+...@googlegroups.com. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/3FBEDB26-E97C-44E2-B088-BDA7DAE4A020%40gmail.com > > <https://groups.google.com/d/msgid/neonixie-l/3FBEDB26-E97C-44E2-B088-BDA7DAE4A020%40gmail.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/f4b9e20a-d7e1-448b-b5a4-174a4d2eccd9n%40googlegroups.com.
