Hickok Color Bars

[old_tv_nut]

Originally Posted by zenith2134

On the models with I/Q bar capability, what would be displayed on a set not capable of decimating the full demodulated signal? Meaning, most all color tv's after the fifties I'm guessing. One day I need to get my hands on an early pattern gen. like these. Using more modern Leader gear now and although they fit my needs, I would like something more era-appropriate for really old tv sets.
John F, that CBS 15" is wonderful

A narrow band set would look essentially like an I/Q set. Color bar generators are not designed to test color bandwidth, only amplitudes and phases of the signals.

[zenith2134]

Bingo, there's my answer. Thanks man! Didn't occur to me that it was a question of bandwidth, even though it makes sense.

[John Folsom]

While we are on the subject of color bar generators.... does anyone have documentation (schematic) for the Jackson model 700 or Jackson model 712 NTSC color bar generators? While recapping one or the other of them some years back, (not sure which), I lost my way, and am left with some dangling components. A schematic sure would save my bacon.

Does anyone own either a Simpson model 430 or GE modes ST- 16A color bar generator? Been looking for these machines for years....

[petepdx]

In a period of 2 weeks I've ended up with three 660's. 2 from one estate. Total investment $10. Are the schematics for the 655 and 656 available ?

[bandersen]

You should get in touch with miniman82. He's missing some crystals in his 660: http://www.videokarma.org/showthread.php?t=260823

[miniman82]

Yes, especially since I contacted the original manufacture of those crystals and they have told me they will only make 50 piece runs... Since I don't see the community restoring 50 Hickok pattern gens, I don't think Bliley will be getting any of my money but you never know- maybe they will find some stock on the shelf. I'm not holding my breath.

They don't even make anything under 1mhz anymore, so that makes the 315khz one unobtanium.

Manual: http://bama.edebris.com/download/hickok/660/660.pdf

[TV'S&MORE]

Originally Posted by petepdx

In a period of 2 weeks I've ended up with three 660's. 2 from one estate. Total investment $10. Are the schematics for the 655 and 656 available ?

I sent MINIMAN82 manual for the 656 a couple of weeks ago maybe he can make you a copy.

[John Folsom]

The Hickok 660 manual can be downloaded from the BAMA website:

http://bama.edebris.com/manuals/hickok/660/

[Tubejunke]

Wow, maybe I should have picked up that early RCA W-64A color bar-dot generator that I posted about not all that long ago. There didn't seem to be much interest at that time, and I was pretty much left at ease that if/when I do need that capability there are other much easier ways of approaching it.

I love vintage test equipment, but I love it to work and be used. I only have the Zenith roundie in a color set, so I won't be using one of those much. In test equipment I really need a REAL capacitor tester and a decent o-scope right now.

[John Folsom]

Here is a schematic for the Hickok 656XC. This generator has a color selector switch selecting 1. NTSC color bars (in a non-standard order), 2. G-Y and G-Y@90degrees bars and 3 R-Y and B-Y bars

Hickok also mad a model 655XC, almost identical except the color selector selects 1 Same as 656XC 2 I and Q bars 3 same as 656XC

Can't seem to lay my hands on the schematic for the 655XC, but if someone needs it, I will keep looking.

[Tomcomm]

I got the beast operating sorta. All the pots are flakey and intermittent after almost 40yrs of open garage storage. Couldn't get contact cleaner into all of them so had to settle for a few rotation sweet spots. I was surprised there was no vertical sync pulses in the video waveform but TVs don't need vertical sync when displaying color bars. The three mode waveform select switches are somewhat confusing. The one three position rotary selects between: COLOR BAR PATTERN, Q-I, and B-Y R-Y. One two position toggle selects between: Q OR B-Y ON and OFF. The other toggle selects between: I OR B-Y ON and OFF. Every body knows the CT100 uses I, Q demod axis and the 21CT55 uses R-Y, Q demod axis. Both of these wide band CTC2 chassis require bar generators that produce a Q axis bar and an I axis bar for the 100CT while the 21CT55 requires a R-Y axis bar! Both RCA and SAMS 21CT55 matrix alignment procedures require a bar generator that produces a R-Y signal in addition to the Q signal. The RCA WR-61A provides all major angles including: I, Q, R-Y, B-Y, G-Y. Hopefully Hickok 655 XC will also? First pic is Sony 26in, second pic is 21CT55 over scanned.

[old_tv_nut]

I would expect a simple V sync pulse to be provided. Maybe something is dead at the end of the timing chain?

[old_tv_nut]

Originally Posted by miniman82

Yes, especially since I contacted the original manufacture of those crystals and they have told me they will only make 50 piece runs... Since I don't see the community restoring 50 Hickok pattern gens, I don't think Bliley will be getting any of my money but you never know- maybe they will find some stock on the shelf. I'm not holding my breath.

They don't even make anything under 1mhz anymore, so that makes the 315khz one unobtanium.

Manual: http://bama.edebris.com/download/hickok/660/660.pdf

Did you ever get a 315 kHz crystal? I think it should be feasible to break the feedback path of the oscillator and install a 555 timer oscillator to drive the grid if you can't get a crystal.

[NoPegs]

Originally Posted by old_tv_nut

Did you ever get a 315 kHz crystal? I think it should be feasible to break the feedback path of the oscillator and install a 555 timer oscillator to drive the grid if you can't get a crystal.

Possibly more accurate to get a 31.5khz crystal and use a PLL to scale it x10. The 555 has way too much drift to be used in this kind of application.

[old_tv_nut]

Originally Posted by NoPegs

Possibly more accurate to get a 31.5khz crystal and use a PLL to scale it x10. The 555 has way too much drift to be used in this kind of application.

Certainly not as good as a crystal, but: to use the color bar function (as opposed to using the generator for a sweep frequency reference) this app needs +/- 1% max tolerance - it's only affecting the H and V frequencies, not the color. The 555 chip itself has a freq tempco of about 90 ppm per deg C. , so I think it would be feasible with a polystyrene cap and small trimpot. Even if it did drift a little too much, you could just turn the pot until the TV set syncs.

Not saying it's elegant, just a way to run without a crystal.