solid state col r tel or colordaptor

[vintagecollect]

Hello,

Has anyone done a solid state col r tel OR colodaptor??

Please let me know, if have schematics and or plans for the sold state version please pm me. Does anyone sell this in a kit form?

[miniman82]

Didn't Cliff do one? There were lots of circuits!

[ChrisW6ATV]

I think on the Antique Radio forum for TVs, there was a big discussion by a man who had built a color wheel and bought an adapter that splits NTSC into sequential color, but I don't think the discussion ever got to a completed, working device. He may have been pretty close, though.

[tubesrule]

vintage:
I make those converters, one of which is for use with the Col-R-Tel. It's not strictly a replacement for the existing electronics, but an improvement over the original. With the original you had to cut into the television for horizontal, vertical and video taps, and start with a tv that had high enough video bandwidth to pass the chroma signal. With the converter, the sequential color video is sent to the tv through RF or line level, so no modification to the tv is required. Because of this you can easily move the color wheel from set to set. All that is required from the Col-R-Tel is the wheel assembly and motor control. If you are ambitious, you can design your own color wheel or drum and motor control like Cliff has done.

Darryl

[vintagecollect]

awesome, tubesrule!

You have done much to help the hobby. Please pm me w/ circuits needed for wheel control, etc. Your avatar is coool! You have a prewar or a reincarnation? Please state converter needed for color wheel and all else needed please. Do you use one of your rigs for the Felix screen shot? Please PM me of low def pre war tv clubs too! Thanks

[tubesrule]

vintage,
The specific converter for this application is the SCRF525M-SC. It was originally created at the request of John Folsom and Cliff Benhem to eliminate the electronics, and especially that nasty commutator in the original Col-R-Tel.

I don't have any specific advice on the mechanics or motor control. Cliff is the resident expert in this area. He has all the numbers for exactly what color filters are required and the motor controls he has used. Cliff is the guy who got the drum set working and donated it to the museum this year.

My avatar is an original RCA publicity picture showing a state of the art (at the time) 60 line mechanical image. I have recreated this on my mechanical sets and actually watched a few shows on them. It's not quite as bad as people might suspect.

Darryl

[vintagecollect]

CAN someone please PM me on any available wheel motor control circuits ss recently done. Post any pis would be great too. HAS ANYBODY hooked one of rigs to a rare prewar set?? You don't have to cut into circuits and modify set, maybe the museum can do this for their next convention in 2012.

[cbenham]

Originally Posted by ChrisW6ATV

I think on the Antique Radio forum for TVs, there was a big discussion by a man who had built a color wheel and bought an adapter that splits NTSC into sequential color, but I don't think the discussion ever got to a completed, working device. He may have been pretty close, though.

I think you mean Pielock. His thread is quite long and he has the test setup to the point where he can take screen shots that look very good.

Here's a link:
http://antiqueradios.com/forums/view...299b1ae46c2828

Good information here about what you will face when building a one-off color wheel set. Not like building a Heathkit or a Dynaco Tube amp at all!

Cliff

[rld-tv01]

There are some pictures on James Hawes web site at http://www.hawestv.com/mtv_slides/benhamA.htm

[ChrisW6ATV]

Yes, that is the one, Cliff.

[vintagecollect]

hello cbenham,

pielock did a great job on his colorwheel. The motor used looks rather small, the setup is very efficient. I'm hoping to hear from him sometime soon.

[mbates14]

I built my colorwheel motor control circuit using a microprocessor.

It takes a long time for the disc to lock because of the "flywheel effect" but it eventually locks, maybe if i apply more braking force against the motor/disc, it will lock faster and suppress "hunting"

But the microprocessor controlled servo that i used, seems to be rock solid once it locks in. works with various types of motors and setups I have tried. I havent messed with it in a couple of years though, other than i got a new hub from cliff. But i scratched the wheel so bad from tucking it away and pulling it back out, that its almost unwatchable. Which reminds me, i need to send his hub back to him, as i had his copied and recessed to hold magnets for the timing pickup.

[vintagecollect]

I'm getting some ideas for the motor speed control, A PWM type for DC motors, A larger DC12v motor for a smaller disc? The hobby shop sells a pricey kit, online has motor control already assembled at a better price. Has anyone here done an opto phase control to synce wheel to picture RGB correctly? any idease please.

[cbenham]

Originally Posted by mbates14

I built my colorwheel motor control circuit using a microprocessor.Which reminds me, i need to send his hub back to him, as i had his copied and recessed to hold magnets for the timing pickup.

That's a great idea! I never thought of embedding magnets in the hub.
Thanks,
Cliff

[old_tv_nut]

Mechanical TV hobbyists make decent servos for the wheel speed when the optical detection pulses are at 400 Hz. I did one for my mechanical TV.


Besides the wheel inertia, however, it is much more difficult to make a decent servo for something at the low rate of 20 Hz that you have with the Col-R-Tel. I never was very successful with getting the 15 Hz mechanical TV wheel to phase up automatically, event though the speed was well controlled.

For what it's worth, the servo development is here:
http://www.bretl.com/mechtvprogress2...o%20design.htm

I think a multiple-pulse-per-rev servo for speed with an added once-per-red-field phase detector of some kind might be worth a try.