On Friday, October 31, 2025 at 2:05:39 PM UTC-4 David wrote:
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. Thanks for the insight! It may be coincidental, but my friend with the Chinese scope clock told me that he needed to reverse the deflection wiring because the 8SJ31 crt seemed to have something loose or out of alignment, requiring him to rotate the tube 180'. Apparently, the display was off-center as built and if the tube was rotated the display would move further off center, as though the gun was shifting - and occasionally a "shadow" would develop on the left side that he attributed to elements in the gun 'drooping' depending which side was up, He found that if he rotated the tube, the display greatly improved. If you slowly rotated the tube while held horizontally as it would be normally mounted, you could hear slight metallic 'pings' from the gun assembly moving inside the tube. In fairness, he also said the package showed signs of rough handling during shipping, so it's possible that his issues result from shipping damage. Still, I found your comment slightly coincidental. Thankfully, I don't 'hear' anything loose in the 3RP1A tubes I just purchased - my B12 sockets should arrive this week and I'll be able to test their performance. -- 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/9cb9f567-2f48-430b-93ce-3985544ad1cen%40googlegroups.com.
