hey all, im working on this 48 motorola table top 7 inch , but as you can see this is a scope 7 inch crt. i went over all resistors unless i missed one but i dont think i did but these lines and rolling i cannot find whats going on here. i subbed tubes and changed resistor values around on the vert hold and vert size but no luck. if i shorten the pic top and bottom with the vert size it will become better stable but i cant widen the screen up and down because it goes crazy. any ideas where i might look as i probably missed something here. these lines may not be there and then they come right back and the longer i leave it on the worse it gets. i even tried another vert pot and vert size pot nothing changed. would something possibly in the IF section do this because upon getting it going for the first time i had nothing, no sound or picture until i rotated the pot for channel 3 and i got picture and the sound but had to rotate a different pot to get the sound good. thing here is there is an old piece of paper tape that had writen on it " if dead" so i dont know if this was an existing problem or not and then i got it with the IF problem. this is why i am wondering if an IF problem would give these lines. one other thing, does anyone here know how to read mics colors, i got a mica that has , red, green , brown , colors ?

You have to look on here, or the net to find the mica colors.....
If there was a bad if section you most likely would get no picture.... Find a
tv block diagram this will show signal path.... Those pronounced lines are
most likely some interference into the vertical osc. or output stage.
You will have to look at the possibility of using a scope to figure out what
is getting in there.....

.

That curved/trapezoid look makes me think the CRT could have a physical problem with one of the vertical deflection plates.

Did you recap the set? Didn't use any 6Kv Ceramic caps in the Vertical did you, those are known to cause problems in that circuit.

These lines are present with both scope crt and a black and white tube and the lines and the rolling seem to stop then start up again. And yes I did recap the set and all the 6kv caps are from just radios no ceramics. Maybe the Micas in the vertice are bad I'll have to consider that are probably bad and change them . Unless there is leakage from somewhere causing this.

this pic of the green 7jp1 is the one i refer to in another post where the brightness up between scenes i get these lines but if i lower the bright the lines wont come back. there has to be a reason for this and at this point i cant find whats going on here. my other set dont do this, but its like if the bright being up its taking something from the verticle and causing it to collapse alittle bit. im lost. :scratch2:

This set has been totally recapped all caps for verticle and horiz. The problem I have is that this set had a 2.5 meg resistor in the bright circuit off the bright pot where a 1 meg resistor belongs and putting the right resistor in makes the lines worse. And the kicker is this wrong resistor was factory , looks like it's been there for 50 years the solder joint look the same as all the others. Maybe there was a screwup when it was wired and this was done to send it out quick, I don't know.

Retrace lines? There are articles on adding retrace blanking circuitry to these sets, only takes a few parts... I'll see if I can find that info again.

i already did the retrace mod.

does anyone here know how to read mics colors, i got a mica that has, red, green , brown , colors ?This page describes one mica color coding scheme:

http://www.tpub.com/neets/book2/3g.htm

Different schemes were used, but this is a common one. First four dots, reading in clockwise order, are: type, 1st digit, 2nd digit, multiplier. In the example given on the page, white-brown-red-red means mica, 1200 pf.

Phil Nelson

Ok thanks, but I'm good now since I changed the Micas that were thought to be bad. Now I'm trying to figure out why these lines appear when the brightness is up.

My friend, if your set plays fine other than vertical retrace lines when the brightness is set too high; I would leave it alone. A lot of early sets had retrace lines I imagine from the factory. This is acceptable performance for what you have if manageable.By manageable I mean that you can pretty much get rid of them by a picture adjustment at user level. The circuitry generally wasn't all that refined in the average consumer set of the say 50s. We must remember that the technology of the times for television was really new.

Yeah, I'd turn down the brightness, button it up and sit in a chair and enjoy!

problem is these lines are not retrace, the common retrace lines that come with these sets i had already but i since done the mod with the cap and resistor and that eliminated all the retrace lines. but if you look at the pic above these are not retrace lines. i have another set that dont have this problem , but its obviously got something wrong here but that is not right having to kill off lots of brightness to not see these lines since i have a crt that performs like new , why waist the brightness to hide a problem.

From the picture you posted above I would say you have a severe vertical linearity issue.

I would recheck cap values and resistor values in the vertical sections to see if you have something out of whack.

well all the caps were done in the verticle the screen adjusts good the way it supposed to be but if the screen scene changes where there is little there to see like only a top bar showing whats on that stuff shows but not befor it pulls down alittle and there it is. otherwise the picture is fine but some scene changes will pull it down alittle to show the lines. its really weird everything has been checked and changed. some resistors are out alittle bit but nothing to do this.

If it's only on some scenes then perhaps the signal is overloading the set? Or Macrovision is causing a problem. What is the picture source?

i went over all resistors unless i missed one but i dont think i did but these lines and rolling i cannot find whats going on here. i subbed tubes and changed resistor values around on the vert hold and vert size but no luck. if i shorten the pic top and bottom with the vert size it will become better stable but i cant widen the screen up and down because it goes crazy.



First I want to apologize. I didn't click on your pic and look closely before assuming that you had retrace lines. Also, I agree if you have a nice, bright CRT you wouldn't want to dim it to the extent that it would take. Frankly, it's bad enough that I can't imagine dimming it making it better unless it was way dim where things are indistinguishable from one another.

I think you were in the right circuit from the get go and I agree with Eric. You have some nasty vertical linearity issues. I used your quote as I noticed (even yesterday) that you say that you "changed resistor values around." That concerns me a bit, but I don't think that you said that whatever you changed made anything worse, so maybe that's OK. It just sounds like you experimentally changed some values as opposed to correcting out of tolerance resistors.

Anyway, the problem is the reason you did that, so what is causing it? A good look at the shot makes me ask if the raster is folded over with the adjustment pot set way too high. That can give the widening traces for sure, but you see them upside down. Maybe a couple of things going on there as far as component issues and adjustment. If you recapped it then the safest thing to say is to check all of your solder connections really good and look for solder drips that have fallen and bridged something. Maybe go over your cap values listed in the schematic from what was installed. There might have been a mistake that took a while to damage a cap and to show its self on your screen

Don't waste your money changing more potentiometers. If you check pots out good with an analog ohm meter and you seen no issue; then there is very little way there can be one if any. Good luck with this! Can you post a pic of the set together and working. We all would probably like to see it. I know I would.

If it's only on some scenes then perhaps the signal is overloading the set? Or Macrovision is causing a problem. What is the picture source?well i come to see now that there are some channels that dont have the lines at all and the source is directv box so maybe its an I F issue because i originally had to turn 2 adjustments to get sound and a picture on channel 3 which both are excellent now so maybe something is out alittle affecting certain channels. and i got this hum that sounds like ac hum in the audio when the volume is at minimum but raise it alittle the hum is gone, and sound is good. is funny i have another set ts18 with none of these issues but this one ts4d is almost the same chassis but i have these issues. :smoke:

[QUOTE=Tubejunke;3140195]First I want to apologize. I didn't click on your pic and look closely before assuming that you had retrace lines. Also, I agree if you have a nice, bright CRT you wouldn't want to dim it to the extent that it would take. Frankly, it's bad enough that I can't imagine dimming it making it better unless it was way dim where things are indistinguishable from one another.

what i did try was putting the right resistors in where they were wrong, made no difference. the brightness resistor, 1 meg but had a 2.5 meg in there and there was a 150k where it was supposed to be a 100k and these resistors were for sure factory so i left the 100k in. but i left the 2.5 meg in the bright circuit as well because when the lines appear they are not bad but putting the right resistor in , 1 meg the lines are really bad when they appear. so i guess ill leave it alone for now.

If it is a Moto TS-4 chassis if an original looking resistor is labeled different from the schematic, consider the schematic to be wrong. The TS-4 went through SO Many production changes that there are literally sets where there is no version of the schematic that is exactly the same as the set....Unless it looks like a part was changed by a previous tech assume it is original and correct (though there may be a 'better' version of the circuit in print).

ok i can see that so ill assume that maybe the oscillator in the I F @ R F is not running right because some channels dont have the lines and others do. i noticed this last night that a high channel didnt have the lines but switched to a lower and they were there.