60's color motorola

[rob Cashin]

I can detune from channel 3 til' i get just snow.. how safe is it to let it run for a few minutes? i dont wanna kill it.. but i will give that a try tomorrow, i thought id get color right when the picture came, i never thought ya woulda had to wait a few minutes to get a color picture

[DavGoodlin]

The round indicator between the hue and intensity controls is will light red when a burst signal is present (indicating color broadcast with correct fine tuning).
In 1965 there were many BW programs and unless color was being broadcast, you did not want to try adjusting those two controls in vain.

Have you tried swapping the five 6BL8 tubes in chroma stages? That would be a good start. If you take the two chroma IF 6BL8s and swap them with the two demod tubes, then swap the color sync amp, FINALLY go after that 6GH8, used as the color osc, you'll need a new one to be sure, those were troublemakers.

When you move set up switch, I was taught to bring each G2 screen control up (these are behind the escutcheon under the brightness and contrast controls) and back it off until the line just disappears, repeat for all three colors. You should have a fairly gray picture when you are done, only then you adjust the green and blue drive controls to finish up. Then turn up the master G2 control next to the screen controls to get the needed brightness.

[DaveWM]

Originally Posted by rob Cashin

I can detune from channel 3 til' i get just snow.. how safe is it to let it run for a few minutes? i dont wanna kill it.. but i will give that a try tomorrow, i thought id get color right when the picture came, i never thought ya woulda had to wait a few minutes to get a color picture

The snow is what you see when no signal is present (a channel with no signal).

color snow shows the color osc is working, generally the color killer is adjusted by switching to an unused channel, and adjusting the color killer until the snow color just goes away and all that is left it BW snow.

Fine tuning is just that, turn the knob to a channel with a signal, then adjust the fine tuning as I described. Is should go from smeary B&W to good color and then if you continue to sound bars in the picture and finally to loss of sync. The correct fine tuning is just before the sound interference on the pic.

did not know it had a burst indicator, nice gimmick.

[rob Cashin]

Well... i have a new 6GH8 coming after chirstmas, I dont have any tubes hanging around that will work with this. I suspect the 6GH8 probably is the problem, if not then Ill just replace every tube one by one. I havent tried adjusting it the way you explained, so in the mean time i'll give that a try.

[DaveWM]

I will make a video in a bit of how to adj color killer and fine tuning later. The color killer is only there to deal with weak OTA B&W programming. You could just set it to max CCW but I like to set things up correctly.

[rob Cashin]

well.. i had one of my friends come over and adjust the tv while it was on. hes clueless about them but he has no fear being back there while its on anyways, i put a tape in the vhs and he was turning the color killer slowly and i got a black and white picture still, but there was stray color in the picture. he touched the vertical lin adjustment in the back and the picture came in the best it has yet, black and white with stray color. i guess this is progress?

[DaveWM]

I see not color at all. the bit at the top is just misconverged macro vision. the pic is general seems snowy I assume you have a matching transformer 75-300ohm. a weak signal will have snow and maybe no color.

[DavGoodlin]

You're getting there. You can probably run it as long as you want BUT don't leave the room while its on, not yet....
Contrast seems lacking, try the AGC control until it gets dark and picture bends, then back it off.
Try cleaning the tuner contacts, looks a bit weak for a VCR source.
The gray scale and retrace lines (dashes across top) show all your colors are working.

Can you get the color indicator light to come on?

[rob Cashin]

yes the colors are working but the tuner does seem kind of weak... could i clean the adjustments in the back or is that asking for trouble? i cant tell what the tubes are doing up there in the tuner.. ill have to pull them out and check out the sockets..

[DaveWM]

Need to clarify some terms.

all the color guns are working (gets a BW pic needs all guns working)

Color is working, color is demodulating, in this case Color is NOT working.

Snow looks like snow generally seen when no signal is present or a weak signal is present. In your case you have snow in the pic. IF no pic and no snow then that would point to a tuner or IF issue.

Snow with pic could be

weak signal from source
bad balun at tuner
bad matching trans if used
dirty contracts (generally you can get a better pic by just messing with tuner by turning it show this up)
weak RF tube
AGC issues

dirty tuner is typical but again just using it (channing channels) will often point to this problem.

there is a correct way to clean a tuner, more on that later if that is the problem.

[Bill R]

You dont need to change or clean the controls in the back. First of all you should be able to get a completely clear B&W picture with a properly connected VCR. There should be no snow. You may need to check or just change the RF amp tube in the tuner or maybe a bad balun. I would also check the IF tubes in the set as well. The fine tunning control will also impact the snow on the screen. Get a good clear B&W picture first. Then worry about the color. You likely have no burst or the chroma oscillator is not working. There is a color indicator light on the front between the color and hue controls on the front. Does it come on while playing the tape. If you cant get it to come on then look at the Burst amp and Chroma Bandpass amplifier circuits. If it comes on but you still have no color the refrence oscillator may not be running. Don't worry about things like demodulator tubes and color set up or convergence yet. That 6gh8 tube may very well be bad and will cause no color. I would bet there are some bad caps in the color circuits as well. On the plus side it looks like you have a good 23EGP22 CRT. That is a plus in itself. You have high voltage, and the horizontal and vertical circuits are working. Looks like a pretty good start and a nice cabinet as well.

[DaveWM]

http://www.youtube.com/watch?v=RAk9lKv03zA

should be ready in about 50min per youtube, covers snow/color killer adj, fine tuning and matching transformers.

One last thing, always think the easy problem 1st. Make sure you VCR is putting out a good clean color pic. See if you have a Known good working tv set and use what ever you cable/transformer setup on that (eliminate as many variable as possible) to confirm you are getting a good signal. Before the loss of analog tv this was easy, now you are forced to use various RF modulators (built into VCR or separates) that may or may not be so good.

[BigDavesTV]

Great start so far! :-) That's a very nice Motorola, definitely worth fixing up, especially since it looks like the 23EGP22 CRT is good. Too bad you don't live closer, or I'd try to help you with it some. That Motorola was about the first (earliest US made) rectangular picture tube set, Zenith and RCA, and many others were still selling those great "roundies" at the same time that Motorola was new. Best of luck with your set.

[maxhifi]

Does the set have more than one 6GH8 in it? try swapping them and see if the symptoms change.

[rob Cashin]

i can get a clear picture i adjusted the AGC and got good contrast and no snow. only thing is theres lines running horizontally at the top of the screen. i havent cleaned the tuner yet, i will in a bit..