Hickok Color Bars
 

I had the privilege of digging through there after oldradio99 and found this Hickok 660. It's dated 1955 and has to be one of the first color dot-bar generators on the market.

http://farm8.staticflickr.com/7301/1...81cbf69e_z.jpg

I have one of the earlier models of the Hickock 660's that is running. Mine is bigger but not nearby to give a model number. It has a different color bar pattern that is pre-NTSC. Just for fun one day I used it to send bars to ESPN for a test in the analog days. I let their heads explode for a minute or so before I told them. Now back to our regularly scheduled thread.

And my memory of the neon xfmr with HV probe is still good!

We called ours the Cattle Prod. :tongue: Used it almost exclusively for 'pre-cleaning' rebuilts before installation. Zap the plug end of the jug to ensure there's no incandescent junk flying around inside. Less liklihood of CRT arcing during operation.

Hickok was one of a handfull of vendors who introduced NTSC color bar generators around 1955-56. Hickok made two models, the 656XC (pictured) and the 655XC.
Both machines produced dot and crosshatch patterns, as well as NTSC color bars (albeit in an unusual color sequence), but the 656XC also produced a R--Y and B-Y bar pattern, and the 655XC produced a I and Q bar pattern.

Hickok 655X Activate
 

John: Your mention of the Hickok color bar generators caused me to remember I had one I used in the '60s when I was first messing with my 21CT55. I dug around in the attic and located it and hauled it to the Lab. Turns out it was a 655X and appeared to be operational less a gassy 5U4 rect and a broken 12AV7 dual triode in the sound section. What interested me was the great wealth of switches for controlling its various video configurations. Seems it will toggle between I or R-Y and toggle between Q or B-Y . A rotary switch selects between COLOR BAR, IQ and B-Y R-Y. A masking tape I stuck on the chassis listed the color bar sequence: GRN YEL RED MAG CYN BLU which agrees with no published logical generated sequence? PROBLEM UNDER CHASSIS: The rear section under the two big xformers has seven pig tail wires coming thru the grommets from the xformers. They were taped and just hanging there disconnected. They are wrapped with plastic tape that I undoubtedly put on 40-50 years ago when it was last operational! The underside photo shows this quite clearly. Is it possible for you or any other member to compare my 655 under chassis with their 655/656 Hickoks and clear-up this mystery for me before I power my 655 up? Any documentation? The 655/656s are excellent examples of the early heroics necessary to produce professional test equipment to design and service the first Roundy Color TVs and should be operational and preserved.

Edit: see below

Tom, I am not in a position to take my Hickok 655 apart. And I cannot seem to lay my hands on my 655 schematic. I can scan the 656XC schematic, if you think that would help.

I would imagine the unique color bar sequence is due to an attempt to dodge someone's patent....?

Curious that there is no white bar mentioned on your masking tape.

Edit - another possible reason for the odd sequence is to generate a pattern with the minimum number of tube multivibrator sections.

ACtually Wayne, it does produce a white bar. And the luminance values are correct for NTSC. Just a curious sequence. Here are the color bars on a CBS RX-90 15" color TV. This is a scan of a photo taken years ago with a film camera, so the color rendition may not be the best.

The irregular bar width seems to indicate a series of monostables rather than a common bar-width clock. Very interesting.

That is exactly right. And it is a bit of a struggle to set up the three one-shot mulit-vibrators to achieve the desired color bar pattern.

This thread has drifted far away from it's original topic, it's been suggested that the posts concerning color bar generators should be moved to it's own thread, sound okay to everyone?

On another note I'm surprised no one has been able to test the 15GP22 yet, seems like it would merit a road trip at least.

Moving them [Edit - I mean the color bar ones] makes sense to me - how about "Hickok color bars"

Hickok Color Bar Order
 

John. Comparing your Hickok 656 top thumbnail with my Hickok 655 top jpg. They both appear almost identical layouts. I would very much welcome your kind offer to scan your 656 schematic. Hopefully it is small enough to fit on one jpg? I’ve looked thru my ‘50's color TV documents, RCA Engineers Digest and IRE preceedings to verify the Hickok generated color bars. They all agree with the order: red, yellow, green, cyan, blue, magenta, white. The masking tape stuck on my 655 lists: green, yellow, red, magenta, white, cyan, blue? Your actual screen shot sorta looks like neither! The 1954 IRE Proceedings first discussed the merits of arranging the order of bar colors to permit a decreasing luminance or monochrome component of 1.00 white down to .11 blue.This produced the current order: white, yellow, cyan, green, magenta, red, blue. I’m looking forward getting my big beast Hickok 655 displaying on my big beast RCA 21CT55 the original official color bars of pre 1954 or my masking tape or whatever! Thanks again for your interest and support....Tom

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:yes: