RCA 21CT55 #8802897 is Dead

[ohohyodafarted]

Tom,

This is absolutely astounding!!! It goes to show that there are people here on VK that have a level of technical expertise that goes above and beyone anything that many of us "re-cap and refinish" restorers like myself, could possibly ever approach.

You have accomplished something that only very few on this forum could have even attempted.

Congratulations, you have my sincere admiration and respect for what you have accomplished!

[Tomcomm]

My screen shots are good, but when I view the actual screens of the 21CT55 and my comb-filtered Sonys I realize my two cameras don't do them justice. Leadike and Wayne have offered possible solutions to increase brightness dynamic range of the shots, Since I don't have Photoshop I've decided to try Wayne's suggestion of processing RAW format on both cameras. This seems daunting but worth the effort. As for Bob's reply, I am most humble. I consider him the primer restorer, both in cabinetry, electronics and CRT rebuild technology. All his projects are museum pieces, including his recent 21CT55, which gives me brief pangs of guilt for what I did to mine in '64. I'll attempt to make it up with some outstanding, RAW based screen shots from my " vertical chassis table model" 21CT55 conversion....Tom

[leadlike]

A cheaper software alternative to Photoshop is the freeware Gimp, which has a lot of pro features. Gimp works very well, it's main flaw (to me, anyway) is that the workflow is a bit clunky. That could be me just being too stuck in my ways with Photoshop, though.

[Tomcomm]

Always wondered how to get BIG pics posted on this forum:




Well that works but its no bigger than the regular VK forum, only 511 X 400 pixals. maybe thats the max size of Picture Trail's URLs...........Tom. So how did Bob G get his full page??

[miniman82]

He probably hosts them off-site.

[Sandy G]

Tom-BLOWN AWAY by yr work....Good Job !

[Tomcomm]

[IMG][/IMG]

Phil.....Putting [IMG] [/IMG] around http://pic70.picturetrail.com:80/VOL.../322339657.jpg
produced same size picture. I'm going to try it next with PhotoBucket.

[Tomcomm]

Phil....The [IMG].............[/IMG] seems to work with Photobucket freebi ok! Its slightly larger than my 1024 X 768
monitor but has positioning sliders to cover entire native pic size. Hey, when I get into posting RAW camera
screenshots this is what its going to be.............Tom

[NewVista]

Do you have vid in mod ?
Can someone link to RCA Video In adapter schematic again please ?

[sampson159]

that looks great!convergence looks very good and the color is fantastic.beautiful picture and thanks for pic

[Tomcomm]

Newvista...........Here's a tube version of the RCA external input driver for the Roundies I got from Pete D. Hope you can use it..........Tom

[NewVista]

Originally Posted by Tomcomm

Newvista...........Here's a tube version of the RCA external input driver for the Roundies I got from Pete D. Hope you can use it..........Tom

Was just thinking your TV must have direct Vid (as well as an amazing CRT)

Thanks to you and others who posted details of this RCA Vid Input, I like the DC restoration & peaking coils.Will try building this one. Meanwhile I adapted another from the net to my CTC-5 that has a tuner problem (details on a separate post)

[Tomcomm]

Since my 21CT55 is not an original RCA restoration but a "laboratory test-bed", I saw no reason to copy RCA's external video input circuitry using early '50s technology. Instead, I implemented a solid-state video op-amp that provides a "perfect" DVD quality 480 line resolution, 75ohm , 5vpp signal into the 55's 1st video amp grid. It also supplies the same 75ohm video at 1vpp to my two comb-filtered Sony monitors and a Leader waveform monitor. Two external video sources can be selected with a toggle switch, each with individual level and offset controls. Presently I run a DVD player with the DVE test disk into one input and a second DVD player with program disks or OTA HD converter into the second input. Now that the 21CT55 's PQ is at least as good as it was before the tragic FBX meltdown I intend to resume my implementation of 480 line component video processing in addition to the present 280 line composite processing, hopefully.......Tom

[cbenham]

Originally Posted by Tomcomm

Newvista...........Here's a tube version of the RCA external input driver for the Roundies I got from Pete D. Hope you can use it..........Tom

Thanks for this link and also for the Broadcast news links posted by Phil Nelson a few messages later.

I've built a few video adaptors for various color sets but all mine have been using basic transistors.

While they work well, they are certainly not as elegant as one using an IC.

Would you share your IC adaptor schematic with the list?
Regards,
Cliff

[Tomcomm]

I use a Signetics NE5539 video op amp. It drives the 1st video amp grid with at least 3vpp and also the video monitors I use for all PQ comparisons.