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:

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.

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

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....

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 ?

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

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

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

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

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

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.

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.

Hickok 655 working sorta.
 

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.

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

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. :yes:

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.

Aligning The Hickok 655
 

MY previous entry indicated the Hickok 655 is producing a marginally acceptable color bar pattern on both the 21CT55 and Sony. However the color bar waveforms indicate a total mess! The Hickok 655 has 19 pots and 6 switches that I "adjusted" by intuition. What is needed is the official Hickok 655 initial setup procedure. Surly this document must exist somewhere possible included in the instruction manual or in some member's memory? Anyone attempting a precise alignment of the two wideband RCA CTC2 CTC100 and CTC2B 21CT55 must be aware that precise setup of the color matrix requires a bar generator having both Q and I bars for the CT100 and both Q and B-Y bars for the 21CT55! Both RCA and SAMS procedures insist on using bar generators that provide 100% saturated R-Y, B-Y, "Q" and "I" video signals. The RCA WR-61A and the Hickok 600 series would be exceptable.
So, any suggestions how I can obtain this information would be appreciated.

http://i677.photobucket.com/albums/v...ps15841e79.jpg

I have no information, but from what those control labels say I'd bet I could set it up properly using a scope on the output and some references to the NTSC standards for what the levels should be for R, G, and B.

From the schematic posted by John Folsom, it appears the phase is set by fixed components in a synthetic delay line (upper right). Unfortunately, the schematic is too fuzzy to read the values, so it might have something to do with the adjustable LC's at the bottom also.

Anyway, it seems you would look at the red, green, and blue bars and adjust the corresponding "Y Gain" for the correct luma level, and the corresponding "Bar Sat" for the correct chroma level. I think this would fix the primary and secondary color bars.
The overall chroma gain sounds like it affects subcarrier on both color bars and I/Q/ whatever, so maybe you would need to adjust it first. If it affects burst level, you would adjust it for that, and then adjust the R, G, B controls.

Hickok 655 much improved
 

Hi Wayne.............Thanks for your reply. I was hoping for some Hickok 655 official alignment procedure would some how show up, wishfull thinking I guess. Surely with 29+ pots available on the top control panel, Hickok had to have an alignment procedure for the poor tech that had to use this analog monster?
Anyway the approach you suggested made sense to me after I realized the RGB "BAR SAT" pots were chrominance settings and the RGB "BAR GAIN" pots were luminance settings! I then rearranged the early RCA color bar order to the strange Hickok color bar order and everything started to come together.