[kbmuri]

Ok, I had to research all this.

The 16RP4 and the 16RP4A both require ion traps. the "A" doesn't stand for "Aluminized", it just stands for "A", and the difference between a 16RP4 and a 16RP4A is unclear. The no-ion-trap replacement for a 16RP4 (or 16RP4A) is a 16RP4B. Only the "B" variant is aluminized (and therefore has a straight gun). For a while, I'm going to go on the assumption that my Capehart 325 has a 16RP4B (tube is unmarked).

The 17BP4 (as in my 333) is more complicated. The original 17BP4 has no aquadag external coating, no aluminized screen, and a clear glass faceplate. The "A" version has an external Aquadag coating. The "B" has the aquadag, and is aluminized. The "C" version has aquadag, is aluminized, and has a gray tinted glass faceplate. This forced me to go downstairs to the gameroom and pull the Capehart 333 away from the wall and reconfirm to myself the "USE NO ION TRAP" sticker, then search the tube for an ID. 17BP4B. So I was, again, guilty of making an assumption, above, that the tube in the 333 was a 17BP4A. It is not an "A", it's a "B". The "USE NO ION TRAP" sticker and the misinformation about the "A" suffix let me presume the rest. From now on, I give no more info "off the top of my head" here, but instead only after verifying and double-checking everything completely. It's important to speak PRECISELY when soliciting opinions here.

The 10BP4 and 10BP4A (as in my Magnavox) both require ion traps, the latter having a tinted windshield. But instead of a "10BP4B", the aluminized version is the 10FP4. No suffix. So you don't necessarily need a "B" suffix (or any suffix) to have aluminization going on. So the moral of the story, I guess, is to RTFM because simple naming conventions don't apply.

I was already misinformed about the "A"-meaning-aluminized rumor before hearing Tubejunke say it a couple of posts ago. I'm sure I read it here on the forum. Just need to make it clear that that's inaccurate and shouldn't be propagated in the future. A is just A. My sources: Sylvania Tube manual (1955), and Radio Shack Tube Substitution Guide (1975).

Other news, I found a Sencore CR-128 CRT Checker/Rejuvenator and a Sencore CG-135 Color Bar Generator at an electronics surplus store in Fort Wayne today, in the "junk heap". Ten bucks for the pair. Cool thing is they match the dimensions and layout of my Sencore TC-136 Tube Checker precisely, looks like I have a matching set. Haven't plugged either one in yet, as they contain a couple of electrolytics each. The CRT checker came with manual and setup guide, the manual having a schematic and parts list. So it should be a no-brainer to get it up and running (maybe yet tonight?). I'll settle the question on the Capehart 325's CRT shortly, that way, if it works and if I can get a "feel" for its accuracy (I have a couple of "NOS" tubes to check against, and one or two untested but well-used-looking CRTs too). My gut feel is that the 325's CRT is fine, based on the original owner's stories, But only an objective test will tell.

The Color-Bar Generator has no manual. Usage is probably completely intuitive, and I don't plan on working on a color set any time in the near future, so no great loss, but if anybody out there has a manual, please let me know.


Small aside, Donald, I'm sure you saved the rejuvenation article to your local PC, then shortcutted to it locally, rather than on the web. The link you provided points to a file on your "E" drive, and is therefore unavailable to anyone but yourself. If you highly recommend the article, I'll need to know where, on the web, you originally found it. Otherwise, thanks a bunch for your suggestions. I'll try them as time allows.

- Kirk