A Confession

[sweitzel]

Yep. The same rings true for any kind of collectable device. I collect 35mm and 70mm film prints. When the movie theaters started converting to digital projection at a rapid pace about 3-4 years ago I ended up picking up many of the same model projector that were headed for scrap metal recycling. There's really not much that can go wrong with a projector head short of gears wearing out over time and the intermittent movement wearing out and failing. Once that happens, the machine is useless. While finding a company that can machine gears is not terribly difficult, there are really no longer any companies left that have the tooling and expertise to manufacture parts and rebuild an intermittent. Hopefully the 4 intermittents I have will last the rest of my life.

[vts1134]

I don't think any one of us is 100% on the side of either of the two extreme examples I gave. I am certainly not suggesting that anyone should be looked down upon because they choose not to give things away at will. As I said in my last post "anyone is free to keep or share anything they see fit." There are things in my collection that I'm not offering up for grabs! What I am saying is that the more people we have in this hobby the better for all of us. I don't think I would be a tv collector if it weren't for the generosity of this community. When we let porthole fly's, Moto yokes, and spare 15GP22s go to others we keep people collecting and that infects others. Just this week I let go of another rare picture tube to another young collector because he needed it for a family set. This was no only my only spare, but it left me with a broken CRT in my set. Someday a 7EP4 will come around again and maybe then I'll have one to replace mine. In the meantime another collector will have the joy of watching a set that means a lot to him, and that means a lot to me to help him.

Sorry to go so off-topic. Moderators edit if you see fit.

[jr_tech]

Originally Posted by vts1134

Just this week I let go of another rare picture tube to another young collector because he needed it for a family set. This was no only my only spare, but it left me with a broken CRT in my set. Someday a 7EP4 will come around again and maybe then I'll have one to replace mine. In the meantime another collector will have the joy of watching a set that means a lot to him, and that means a lot to me to help him.

So why not make an adapter socket, and substitute a common 7JP4?

jr

[benman94]

Originally Posted by jr_tech

So why not make an adapter socket, and substitute a common 7JP4?

jr

In general, a 7JP4 won't sub all that well for a 7EP4, the difference in HV is too great. The 7EP4 needs about 2 or 3 kV, a 7JP4 is around 6 kV I think. A 5BP4 is a better sub, being electrically identical, despite the smaller screen, and actually cheaper than a 7JP4. A 7GP4 would probably work though...

[vts1134]

Originally Posted by jr_tech

So why not make an adapter socket, and substitute a common 7JP4?

jr

I'm a stickler for originality. I've seen 2 7EP4's for sale in 5 years so another one is due to come up in 3 years or so.

[maxhifi]

Originally Posted by sweitzel

Yep. The same rings true for any kind of collectable device. I collect 35mm and 70mm film prints. When the movie theaters started converting to digital projection at a rapid pace about 3-4 years ago I ended up picking up many of the same model projector that were headed for scrap metal recycling. There's really not much that can go wrong with a projector head short of gears wearing out over time and the intermittent movement wearing out and failing. Once that happens, the machine is useless. While finding a company that can machine gears is not terribly difficult, there are really no longer any companies left that have the tooling and expertise to manufacture parts and rebuild an intermittent. Hopefully the 4 intermittents I have will last the rest of my life.

I think that paragraph just about blew my mind... you have the ability to project 35 and 70MM FILM at HOME!? WOW! I thought that hobby was for eccentric millionaires

[sweitzel]

Originally Posted by maxhifi

I think that paragraph just about blew my mind... you have the ability to project 35 and 70MM FILM at HOME!? WOW! I thought that hobby was for eccentric millionaires

I don't want to derail the OP's thread too much so I'll keep it brief. Yes it's not only possible to collect and project 35 and 70, it isn't as expensive as you think if you are patient and have good contacts. It took me a long time to work up to the 70mm however. I mostly bought prints in the 90's from a now defunct classified ad magazine called "The Big Reel". Prints averaged from $150-$350 usually back then. I bought a WWII era "portable" 35mm projector and could only run one 20 minute reel at a time. In 2008 I acquired my first dual gauge 35mm/70mm machine and started accumulating the sound processors for the different kinds of audio tracks. That machine also allowed me to use large enough reels to hold an hour of film so only one re-thread per show. Now I have a full blown system with platters and and everything but my print collecting days are pretty much done and I sit on my 45 or so titles I've kept. The magazine is gone, and what titles get put on ebay are being "panic bought" by film archives and "eccentric millionaires" Just last week a print of Raiders of the Lost Ark got bid up to $4585. Ridiculous. That used to be a $350-$500 title not too long ago. Maybe I'll make a thread on the subject in another subforum.

[wiseguy]

This Tech Tip from Worked for me years ago, could be a new idea for you, I am not sure what set that I tried it on its been awhile
I have problems with windows 10 and this site, I try and rotate but it still loads sideways

[Josef]

Hi!

Sorry, but in my opinion the best way would be rewinding the donut. Has anybody ever tried that or finding a company who is able to do so. If not what are the reasons?
O.k. the diameter of the wire is real thin but on the other hand if it was possible winding a HV coil 60 years ago it should still be possible today- or am I wrong?

Greetings Josef

[old_tv_nut]

Originally Posted by Josef

Hi!

Sorry, but in my opinion the best way would be rewinding the donut. Has anybody ever tried that or finding a company who is able to do so. If not what are the reasons?
O.k. the diameter of the wire is real thin but on the other hand if it was possible winding a HV coil 60 years ago it should still be possible today- or am I wrong?

Greetings Josef

Possible, but you may get a different high voltage or different "stiffness" (variation with current) of the high voltage from the original, as it may vary with the dielectric constant of the potting compound, which affects the resonant frequency of the secondary. The difference in stiffness will not be a great worry in a set that uses a shunt regulator.

[Josef]

If an used and untested flyback goes up that much, rewinding should be definitely worth a try or maybe more attempts.

Greetings Josef