CurtPalme.com Home Theater Forum

[banzairun]

This is probably boring stuff -- I pretty much just want to mess with the fun high-end sets as well

..but these are sort of irreplaceable (if I want to keep them original) and I have about 8 of these units I'd like to re-tube.. these are special-purpose 24kHz-only Mitsubishi sets that were first made around 1992, but were in production until about 1998. They do not use grid 3 for focus at all, but do have a typical sort of EM focus yoke similar to the nice sets we all use, and a small pot on a board for focusing each color that has a lot of range. There is no G2/G3 pot block at all.

The question I have is that I haven't seen this sort of setup on any typical consumer sets I've run across -- which are the best source for donor 7" tubes for this sort of thing. I've found that pretty much any tube from the 90's, no matter what the P16XXX number is (or 180DLB22) works in any other typical set from the era, but these are so different that I'm seeking a second opinion..

..since these are mits sets, they have their own tubes with a slightly different setup.. These are type VT07M71AB22, and the anodes are on the side of tube. They have the exact same tube envelope as any P16 tube, though. Considering the anodes are daisy-chained (no splitter block), it's a massive pain to try dropping some P16s into one of these and just hope it works.

So before I start giving this a try, I was hoping somebody might have some insight? I'm sure the anode, neckboard and LC chamber stuff probably will drop in fine, beyond being time-consuming, but the concern is if P16 tubes will focus correctly? I haven't run across any mits sets that use a similar setup, so dropping in common P16s seems to be the only option since I have so many of these I'd like to swap out.

These VT07 tubes are longer-neck than most P16 tubes. I haven't found a problem in swapping short neck and long-neck P16 tubes with each other in projectors with standard pot blocks for the grids. Focus is good enough since these aren't great quality sets to begin with ..but since these particular sets are EM focus-only, will the typical shorter tubes from ES focus sets even work at all? or should I use the P16 tubes from the year 2002+ RP sets that all seem to have EM focus? I've found that those tubes arc internally somewhere with G2 turned up to a usable level in the ES focus sets, and are therefore totally unusable, so I'm guessing the grids are closer to each other in them. Would this type of tube be more likely to work?

..Or if you may know of some other sets that use this sort of setup that I can seek? I have not seen mits consumer sets with this arrangement, but I've only ever dug into about 10 of them..

I'm just trying to lay out all my options here, but this probably isn't something many people have run across.. Seems like something Charlie from VDC might know, if anybody knows how to bother him. :/

[the big E]

Match the number on the tubes as most if not all projection tvs are em focus

Plus if you don't match the numbers you could damage more then its worth

[banzairun]

Tubes numbers in these sets matter less than you might think.. I've swapped tubes out of a dozen sets and basically found that there are two "tube types", no matter the number. I junked 20-30 consumer sets from the same era and never found a similar tube number, but using a dozen different tube numbers with varying neck lengths; they're all compatible and work fine enough for the purposes of these things (I'm talking about a similar 24kHz special-purpose set -- basically the same as this Mits one, but made by Toshiba, with ES focus).

It's just tough with Mitsubishi in this case since they used their own tubes, and the anode setup in these is different even from any mits set I've seen -- I probably need early 90's sets to find something similar, but I'd rather use later P16s or something along those lines as they will probably have greater emission. I've found nothing similar to these sets so far; they're more similar higher end front projectors.

and FWIW; all of the lower-end sets (ie: the majority of what is out there from what I've seen from junking them) are ES focus. It doesn't matter if these things get damaged anyway -- they already have unusable tubes. I can burn up a few if I have to, but I'd obviously prefer to avoid that. There is no replacing the cabinets these are in, so I'd MUCH prefer to avoid gutting the projector and sticking crappy 42" LCDs in their place.

[CasetheCorvetteman]

Most rear projection TVs are ES focus.

[the big E]

Most but not all are es focus

Good to know the tube numbers don't have to match if I ever need tubes for my samsung

[the big E]

I found my p16 red tube online from a supplier(its a 8incher)

I can provide the link if you want it