Re: [neonixie-l] Scope Clock SC200C
The brightness pot needing to be turned right up still suggests that you have a problem with grid voltage control. I'd expect to see some higher frequencies much higher than 60Hz on the BLNK- signal as well though. I'd be surprised if the problem was in the supply sections for the cathode or anode given that it is mostly working in your photo but there could be an issue with the specific section of the supply dedicated to the grid and it is referenced to the cathode. Although you have now replaced most of the potentially offending components unless you have an open winding on the transformer. You could check the resistance across pins 4,5 and 6 of the transformer. I'd expect them all to read fairly low. On Tuesday, October 26, 2021 at 10:20:26 AM UTC+10 GEK wrote: > Ok, so I'm stumped (again)... > > I have replaced D35-38, C52, C53, C54, C55, Q1, C51 and U17. > R67, F68, R69, R70 and R71 measure correctly in circuit. > I've confirmed pulsing on the BLNK- signal at 60hz > I've also swapped U5 (74HC74) and U4 (74HC151). > I've swapped the CRT. > > Curiously I need to have the Bright potentiometer (R11) at maximum to get > an image. > Could something in the High Voltage Supply be causing problems with the > blanking? > > On Thursday, October 21, 2021 at 3:05:10 PM UTC-4 Paul Andrews wrote: > >> Hah yes. I have one of its brethren that is even more 'eclectic'. >> >> On Wednesday, October 20, 2021 at 8:04:03 PM UTC-4 Terry S wrote: >> >>> >>> That may just be one of the worst PCB layouts I've ever seen. >>> On Wednesday, October 20, 2021 at 8:33:41 AM UTC-5 martin martin wrote: >>> Here's a simple one https://www.tindie.com/products/howchon/osc45-oscilloscope-clock-kit-for-many-crt-types/ ~ *mcve...@gmail.com* On Wed, Oct 20, 2021 at 4:16 AM GEK wrote: > Will do, Hopefully parts will be here by Friday. I may try and > shotgun D35-38 and C52-53 before then as I should have spares around here. > > Finger's crossed! > > - Gary > > On Wednesday, October 20, 2021 at 1:19:58 AM UTC-4 Tristan wrote: > >> Hi Gary, >> >> That's a bit odd. While I'm no EE I would have expected that removing >> U17 would have blanked the display if the rest of the circuit was >> working >> correctly. It looks Q13 should be conducting without U17 fitted and the >> grid should become more negative with respect to the cathode to ensure >> cutoff. I think you may need to look at the D35-38 and C52 & C53. >> >> - Tristan >> >> On Wednesday, October 20, 2021 at 12:42:53 PM UTC+10 GEK wrote: >> >>> Tristan - >>> >>> Thanks for those hints. the BLNK signal is pulsing at 60hz, and I >>> swapped Q13 without any change. I also socketed U17 (6N137) while >>> waiting >>> for a replacement to arrive. Removing U17 from the circuit leaves the >>> display unchanged, so it does appear that the blanking circuit is the >>> culprit. >>> >>> I'll swap U17 once it arrives - and if that doesn't fix things start >>> shotgunning the passives. >>> >>> Thanks again for the guidance, very appreciated! >>> >>> - Gary >>> >>> On Tuesday, October 19, 2021 at 10:04:24 PM UTC-4 Tristan wrote: >>> Also the voltage between the cathode and the blanking section should be checked (I.e. the voltage across C51) and R65 and R67 should be checked (or potentially replaced along with C51 if shotgunning it). The rest of the high voltage supply appears to be working. - Tristan On Wednesday, October 20, 2021 at 11:50:56 AM UTC+10 Tristan wrote: > 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
Re: [neonixie-l] Scope Clock SC200C
I dont have the same exact scope-clock, but with mine the intensity, focus, and astigmatism adjustments all interplay with eachother. Mine uses an 8SJ31J tube, and there is a test-point where you can verify the HV is correct. It should measure 300V. On Monday, October 25, 2021 at 5:20:26 PM UTC-7 GEK wrote: > Ok, so I'm stumped (again)... > > I have replaced D35-38, C52, C53, C54, C55, Q1, C51 and U17. > R67, F68, R69, R70 and R71 measure correctly in circuit. > I've confirmed pulsing on the BLNK- signal at 60hz > I've also swapped U5 (74HC74) and U4 (74HC151). > I've swapped the CRT. > > Curiously I need to have the Bright potentiometer (R11) at maximum to get > an image. > Could something in the High Voltage Supply be causing problems with the > blanking? > > On Thursday, October 21, 2021 at 3:05:10 PM UTC-4 Paul Andrews wrote: > >> Hah yes. I have one of its brethren that is even more 'eclectic'. >> >> On Wednesday, October 20, 2021 at 8:04:03 PM UTC-4 Terry S wrote: >> >>> >>> That may just be one of the worst PCB layouts I've ever seen. >>> On Wednesday, October 20, 2021 at 8:33:41 AM UTC-5 martin martin wrote: >>> Here's a simple one https://www.tindie.com/products/howchon/osc45-oscilloscope-clock-kit-for-many-crt-types/ ~ *mcve...@gmail.com* On Wed, Oct 20, 2021 at 4:16 AM GEK wrote: > Will do, Hopefully parts will be here by Friday. I may try and > shotgun D35-38 and C52-53 before then as I should have spares around here. > > Finger's crossed! > > - Gary > > On Wednesday, October 20, 2021 at 1:19:58 AM UTC-4 Tristan wrote: > >> Hi Gary, >> >> That's a bit odd. While I'm no EE I would have expected that removing >> U17 would have blanked the display if the rest of the circuit was >> working >> correctly. It looks Q13 should be conducting without U17 fitted and the >> grid should become more negative with respect to the cathode to ensure >> cutoff. I think you may need to look at the D35-38 and C52 & C53. >> >> - Tristan >> >> On Wednesday, October 20, 2021 at 12:42:53 PM UTC+10 GEK wrote: >> >>> Tristan - >>> >>> Thanks for those hints. the BLNK signal is pulsing at 60hz, and I >>> swapped Q13 without any change. I also socketed U17 (6N137) while >>> waiting >>> for a replacement to arrive. Removing U17 from the circuit leaves the >>> display unchanged, so it does appear that the blanking circuit is the >>> culprit. >>> >>> I'll swap U17 once it arrives - and if that doesn't fix things start >>> shotgunning the passives. >>> >>> Thanks again for the guidance, very appreciated! >>> >>> - Gary >>> >>> On Tuesday, October 19, 2021 at 10:04:24 PM UTC-4 Tristan wrote: >>> Also the voltage between the cathode and the blanking section should be checked (I.e. the voltage across C51) and R65 and R67 should be checked (or potentially replaced along with C51 if shotgunning it). The rest of the high voltage supply appears to be working. - Tristan On Wednesday, October 20, 2021 at 11:50:56 AM UTC+10 Tristan wrote: > 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 pa
Re: [neonixie-l] Scope Clock SC200C
Ok, so I'm stumped (again)... I have replaced D35-38, C52, C53, C54, C55, Q1, C51 and U17. R67, F68, R69, R70 and R71 measure correctly in circuit. I've confirmed pulsing on the BLNK- signal at 60hz I've also swapped U5 (74HC74) and U4 (74HC151). I've swapped the CRT. Curiously I need to have the Bright potentiometer (R11) at maximum to get an image. Could something in the High Voltage Supply be causing problems with the blanking? On Thursday, October 21, 2021 at 3:05:10 PM UTC-4 Paul Andrews wrote: > Hah yes. I have one of its brethren that is even more 'eclectic'. > > On Wednesday, October 20, 2021 at 8:04:03 PM UTC-4 Terry S wrote: > >> >> That may just be one of the worst PCB layouts I've ever seen. >> On Wednesday, October 20, 2021 at 8:33:41 AM UTC-5 martin martin wrote: >> >>> Here's a simple one >>> >>> https://www.tindie.com/products/howchon/osc45-oscilloscope-clock-kit-for-many-crt-types/ >>> >>> >>> >>> >>> >>> ~ >>> *mcve...@gmail.com* >>> >>> >>> On Wed, Oct 20, 2021 at 4:16 AM GEK wrote: >>> Will do, Hopefully parts will be here by Friday. I may try and shotgun D35-38 and C52-53 before then as I should have spares around here. Finger's crossed! - Gary On Wednesday, October 20, 2021 at 1:19:58 AM UTC-4 Tristan wrote: > Hi Gary, > > That's a bit odd. While I'm no EE I would have expected that removing > U17 would have blanked the display if the rest of the circuit was working > correctly. It looks Q13 should be conducting without U17 fitted and the > grid should become more negative with respect to the cathode to ensure > cutoff. I think you may need to look at the D35-38 and C52 & C53. > > - Tristan > > On Wednesday, October 20, 2021 at 12:42:53 PM UTC+10 GEK wrote: > >> Tristan - >> >> Thanks for those hints. the BLNK signal is pulsing at 60hz, and I >> swapped Q13 without any change. I also socketed U17 (6N137) while >> waiting >> for a replacement to arrive. Removing U17 from the circuit leaves the >> display unchanged, so it does appear that the blanking circuit is the >> culprit. >> >> I'll swap U17 once it arrives - and if that doesn't fix things start >> shotgunning the passives. >> >> Thanks again for the guidance, very appreciated! >> >> - Gary >> >> On Tuesday, October 19, 2021 at 10:04:24 PM UTC-4 Tristan wrote: >> >>> Also the voltage between the cathode and the blanking section should >>> be checked (I.e. the voltage across C51) and R65 and R67 should be >>> checked >>> (or potentially replaced along with C51 if shotgunning it). The rest of >>> the >>> high voltage supply appears to be working. >>> >>> - Tristan >>> On Wednesday, October 20, 2021 at 11:50:56 AM UTC+10 Tristan wrote: >>> 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 wrote: > > > > > On Oct 18, 2021, at 7:53 PM, Gary Kaufman > wrote: > > I've now got a stable, but scram
Re: [neonixie-l] Re: Homemade Purple Nixie Tube
I have also long been interested in doing neon tubes for fun, as well as lasers and other fun things. I have both diff pumps and a turbo pump which I want to configure into a vacuum workstation built on an old ultracentrifuge chassis. So I was looking at neon sign electrodes as a possible starting point for some of this stuff. Would placing a cold trap inline before the turbo pump capture any possible mercury or other contamination? I would think that the vapor would be pulled through by the roughing pump anyway. Am I correct in remembering that some diff pumps actually used mercury versus oil? I'm pretty sure the two I have both used oil. One was from ebay, the other from the aforementioned ultracentrifuge. At least one of my 3 Welch rotary vane roughing pumps needs a rebuild (if not all of them). Man, rebuild kits have skyrocketed in price! Haven't tested the other, more modern roughing pump yet. On Sun, Oct 24, 2021 at 11:10 PM joshua dejaen wrote: > I have an edwards e2m1 that I bought used for $200 which theoretically can > reach .38 microns. > > Its pumping speed however is slow and my rubber stoppers are not helping. > My thermocouple gauge burned out unfortunately so I can't measure my > current vacuum but I would not be > > surprised if I was achieving 5 microns or lower after extended pumping. > > A diffusion pump is not necessary in my opinion for experimenting, but > probably is needed if you want to make a tube that will last for decades. > > Bombarding is an issue I have not solved, I currently just heat the tube > with the torch for a while pumping to remove impurities and call it good. > > This leaves the electrodes unprocessed however and will lead to a shorter > life. > > Simplifier and myself have both also both made functional Triodes using > nothing more than a rotary vane pump, and he was able to achieve below 5 > microns with his generic Chinese > > pump. > > > Here is a link to Simplifier making a helium discharge tube using only a > cheap rotary vane pump https://simplifier.neocities.org/discharge.html > > And his Homepage https://simplifier.neocities.org/index.html > > He has a whole list of vacuum and glass related projects and does them in > the simplest way possible. > > > > > > > On Sunday, October 24, 2021 at 7:03:38 PM UTC-7 gregebert wrote: > >> Did you need to use a diffusion pump to get below 10 microns ? Years ago >> I researched doing neon tubes, but got discouraged by the high-cost of the >> vacuum equipment and the dangers of bombarding. >> >> On Sunday, October 24, 2021 at 11:32:33 AM UTC-7 Chuck wrote: >> >>> I distinctly remember some of Dalibor's first tubes from mnay years ago >>> when he first started experimenting. >>> >>> He made one that looked a lot like this one. Nice Work! >>> >>> Chuck >>> >>> >>> >>> >>> Original Message >>> From: "joshua dejaen" >>> Sent: 10/24/2021 2:36:14 AM >>> To: "neonixie-l" >>> Subject: Re: [neonixie-l] Re: Homemade Purple Nixie Tube >>> >>> Thanks for all the comments, sorry I could not reply sooner. >>> >>> I have added mercury to glow tubes in the past but I have not wanted to >>> contaminate my new pump. >>> >>> I could do it on my old pump but it is not able to pump below 1 torr and >>> the tube would be left with impurities. >>> >>> My electrodes consist of copper welded to tungsten with a nickel buffer >>> and then the tungsten welded to nickel wire that forms the digits inside >>> the tube. >>> >>> The tungsten forms the actual seal to the pyrex glass and the copper >>> provides a nice external lead. >>> >>> I heat up the tube with the torch while pumping for about a minute and >>> let it pump under high(ish) vacuum (5-10 microns) for 30 min. >>> >>> I then open the bleed valve and adjust the pressure until the glow looks >>> good and seal it off. >>> >>> I also have made Triodes in the past and those require about 15 min >>> heating with the torch on the pump along with an hour of pumping. >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> On Wednesday, October 20, 2021 at 12:49:28 PM UTC-7 nickja...@gmail.com >>> wrote: >>> I don't recall for certain if it was NeonJohn or another guy, or even what group it was in. Could've been the old geigercounterenthusiasts group on yahoo. This was some time ago, when we were laughing about the insane overreaction to breakage of CFLs in school classrooms. I've never tried opening a tube in a controlled fashion myself, but have seen tiny droplets in broken ones, usually near the ends of the tube. Been playing with glass laser tubes a little the last week. Found that Gammex patient positioners used both red and green HeNe before diodes took over. Got one that won't lase though the plasma tube is a nice bright pink. It hisses or buzzes continuously but no beam output. The PS is good as it lit up a couple of similar size d tubes last night when I tried. I need to completely remove it and try si
