there are an awful lot of P1 CRTs in small sizes for sale on ebay, and laying around in guys workshops. I have at least 3 in the room I'm sitting in. I don't expect there will be a shortage of them any time soon. P4 tubes in small sizes? sure, they're hard to find.
On Wednesday, October 29, 2025 at 6:04:16 PM UTC-7 Instrument Resources of America wrote: > Pilot Radio Company made a three inch black and white television in the > late 1940's early 1950's. It was the first television to break the $100.00 > price tag, on the low side. It's CRT IIRC was a 3RP4 with P4 phosphor. > These sets are highly prized by collectors, including myself. I have one > currently under restoration, with a good CRT. Unfortunately many of these > sets do NOT have good CRT's. and the folks who have them have resorted to > using the 3RP1's and this of course is adding to their shortage. Making > clocks with them is also adding to their shortage, along with the collector > crowd. > > Ira. > > > > On 10/29/2025 4:25 PM, Tom Katt wrote: > > They are hard to find for some reason lol. I stumbled upon them by > accident even though I was searching for 3RP1's. Mine just arrived today > - well packaged and factory sealed boxes. I haven't hooked them up yet, > but they are obviously new and look nice so I do not expect any issues. > > LOT OF 3 Oscilloscope Vacuum Tube 3RPI-A | eBay > <https://www.ebay.com/itm/235029032080> > > > > On Wednesday, October 29, 2025 at 12:11:58 AM UTC-4 [email protected] > wrote: > >> Tom, >> >> Can you post a link to the eBay listing for the 3RP1A tubes? I was not >> able to find it searching with the “I” or “1”, looking in both current and >> completed listings. >> >> Thanks, >> Randy >> >> >> On Oct 28, 2025, at 6:15 AM, TomJ <[email protected]> wrote: >> >> >> >> Forgot to mention - if anyone else is considering a crt clock project, >> brand new Chinese 3RP1A tubes are available from US sellers on eBay (3 for >> $85 shipped). But they are listed with the letter "I" instead of the >> numeral "1" - the eBay search doesn't pick up on that, so they are easily >> overlooked. I think these are the same ones that Sphere used to sell. >> >> On Tue, Oct 28, 2025 at 6:07 AM TomJ <[email protected]> wrote: >> >>> >>> >>> On Mon, Oct 27, 2025 at 4:31 PM Mac Doktor <[email protected]> wrote: >>> >>>> >>>> Note that over at the GeigerCounters group talking about building >>>> negative HV power supplies can get you banned. A couple of people found >>>> that out the hard way after having been warned. The -900V supplies in >>>> Geiger counters are grandfathered in, of course, and the currents are very >>>> low. >>>> >>>> >>>> >>> Certainly, the voltages involved are no joke and can be lethal. CRT >>> voltages typically are very low current as well, but I suspect still very >>> dangerous. Though it seems a bit >>> nanny-state' to ban legitimate scientific discussions - you can just as >>> easily discover mortality working on your car or a home appliance. >>> >>> In any event, I also received a very informative email from the >>> gentleman at Sgitheach... My understanding is that the crt tube doesn't >>> really care - it comes down how you want to design your circuit. Having >>> the high potential at the cathode makes the deflection circuit easier to >>> implement because the voltages are lower. BUT, if you desire to >>> incorporate some kind of intensity modulation or Z axis, you now have to >>> manage that end with high voltages. The end result from a performance >>> perspective will be the same. >>> >>> Thanks for the insight! >>> >> -- >> >> 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 [email protected]. >> >> To view this discussion, visit >> https://groups.google.com/d/msgid/neonixie-l/CAArLthczeXYLQnthL6gLGVEt%3DsTB1P%2B%2BfOzE-bRh82g2gZEmtA%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/neonixie-l/CAArLthczeXYLQnthL6gLGVEt%3DsTB1P%2B%2BfOzE-bRh82g2gZEmtA%40mail.gmail.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 [email protected]. > > To view this discussion, visit > https://groups.google.com/d/msgid/neonixie-l/8bbf7557-7e62-4da8-a6cc-543318d4c00an%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/8bbf7557-7e62-4da8-a6cc-543318d4c00an%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 [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/c0dda752-ecb0-4ad2-95ec-5241810b793en%40googlegroups.com.
