Re: [neonixie-l] Re: CRT "Scope Clock" - Power Supply Question

[David]

The 3RP1-A CRT is a flat face tube. It cannot maintain focus across the face as well as a curved face 3RP1 tube because of that. And it’s true that the Chinese tubes tend to defocus at the right side of the screen, possibly due to the electron gun structure not being entirely symmetrical. The H deflection plates are closer to the screen, so they require more voltage per mm of deflection.  I have adjusted the displays of literally hundreds of these CRTs. They are remarkably consistent in their quirks.  Also, I don’t have any information about when they were manufactured.  David Forbes, Tucson AZ On Oct 30, 2025, at 2:32 PM, Nicholas Stock <nickst...@gmail.com> wrote:  I always thought the 'A' designation meant their specs were better.... On Thu, Oct 30, 2025 at 12:18 PM Dekatron42 <martin.forsb...@gmail.com> wrote: Interesting feedback comment from one buyer of these CRT's: "Tubes are bright BUT out of focus on the edge typical of 3PR1 A model 3RP1A are not as good as 3RP1.....put them in the oscilloscope then sell it at a ham fest quick" /Martin On Thursday, 30 October 2025 at 18:40:09 UTC+1 Tom Katt wrote: On Thursday, October 30, 2025 at 1:23:02 PM UTC-4 Mac Doktor wrote: On Oct 30, 2025, at 7:29 AM, Tom Katt wrote: Atari Tempest was my game back in the day The best of the bunch. I used to have one but it was too big and underutilized so it had to go. It had the rare early version of the marquee plus the image was square, not pin cushioned. Paid $65 in working condition, got $500 for it. I always yearned for one but alas I never found one I could afford.  I don't play a lot of video games anymore, but I did invest in building a nice arcade quality control panel for a MAME emulator.  Every once in a while I get the urge to spin the knob ;-)  Things are fun until I get to the invisible levels, and then it's chaos lol. Though I can't really complain - I have stumbled upon more than my share of fantastic deals...  About 20 years ago I saw an advert in the local paper for a _free_ pinball machine - just come get it off their porch.  It was an 80's Bally Centaur - one of the first with synthesized speech!  And can you believe that about $20 in solenoid driver transistors is all it needed?  Between the artwork and the gameplay this pin is still hghly sought after and commands good money.  I'll leave it to a nephew in my will lol.  And then there's the NYC traffic light (complete with aluminum base, pole and authentic graffiti lol)...  Happened to be driving by construction where they were replacing the old glass signals with leds and asked what happens to the old ones - I found out they fit in the back of an SUV if you position it correctly ;-) -- 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, visit https://groups.google.com/d/msgid/neonixie-l/9adcf12a-48b8-4121-85e2-d63e639e2349n%40googlegroups.com. -- 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, visit https://groups.google.com/d/msgid/neonixie-l/CAOX%2BRHJRKVCvNLsZZ6NXLbqmz06xFQoektrBat4kO27R-2yocw%40mail.gmail.com. -- 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, visit https://groups.google.com/d/msgid/neonixie-l/7E0A80D6-87E7-4283-A6E2-41CEAE76C7A0%40gmail.com.