Picture Tubes and Rebuilding
 

Is there anywhere to get rebuilt picture tubes anymore? Are they still going to someday rebuild the picture tubes in Ohio with the equipement that they acquired from Hawkeye in Iowa?

I think they only plan to rebuild early B&W and roundie color CRTs.

There is no one currently rebuilding picture tubes. You can read more about the ETF project by following these links

http://www.earlytelevision.org/crt_project.html

http://www.videokarma.org/forumdisplay.php?f=185

Wow this is more than I ever imagined would be possible...I really hope this will work.

Yeah, but even if they do make a go of it, would it be of any benefit to those of us who are into the "newer" stuff?

Well on "newer" stuff you're less likely to have to re-phosphor the face, so in theory if there's a compatible gun/stem available it could be swapped in with some level of success. Also of benefit to gassy tube owners (metal cones take a number.) with potential ability to re-evacuate the bulb if the leak can be located with a mass-spec probe and sealed with frit or other vacuuseal type stuff.

Keep in mind that color tubes can't be rephosphored (I doubt anyone even did that back in the day). The complexity of dismantling the screen from the bell (without damaging the shadow mask), reapplying a grid of VERY tiny and precise phosphor dots, realigning/attaching the shadow mask and reassembling the whole thing would be prohibitive.

That being said, I reckon it's a bit too late for this one:

Ooh, that's pretty.

I bet that'll buff right out.

Couple taps with a sledgehammer and i bet you wont be able to notice it.... :D

SR

You are right, no-one could re-phosphor color tubes. Each tube/yoke type needed a matching light-house optics to expose the photo resist for depositing the dots. Plus, I seem to recall something about the negative guard band tubes being exposed and phosphored while the mask still had small holes, which were later enlarged before final assembly. Anybody know about that for sure, or am I dreaming?

The thought occurs to me that today you could add programmable dynamic purity coils to a CRT and adjust the purity for whatever mismatch occurred in the re-phosphoring. This of course would be more complex than the whole circuit of the original set, but it seems conceivable.