ctc12 clone beam current

[timmy]

Originally Posted by Electronic M

I don't know for sure on your set, but on CTC-15 clones I have the boost supplies the high voltage side of the CRT screen/G2 potentiometers, and IIRC the vertical linearity control pot.

On my Silvertone CTC-15 clone there was an SS boost diode that was bad when I repaired my set. Your set may be the same or different so take this with a grain of salt.

i think my other silvertone has that diode but not this old 63 , boy for a freebie this set has been truly a thorn in my side for sure,lol..

[DaveWM]

does the focus voltage vary from about 4k to 5k, I use a simpson 260 to check.

Its easy to miss wire a focus coil.

[timmy]

in focus, the voltage is just befor 5kv and yes it will vary and i looked at the sams for the position of the taps to make sure i had it right. wired wrong may give all this headache.

[DaveWM]

it should very about 1kv
you have to becareful about those focus coils, often they are generic replacements with extra lugs or lugs that are in different orders. Generally you use the included instructions when replacing. they are variable transformers that vary both phase and amplitude adding or subtracting from the voltage going to the focus tube.

what was the problem with the orig FLY?

[timmy]

there was no problem with the old fly i had a new one and decided to change it thinking the fly was the problem with the hv, but it made no difference.

[Bill R]

Use the HV probe to check the B+Boost, or a VTVM. Most DVOM meters do not measure a high enough voltage. I use an RCA Senior voltohmist VTVM on the 1500 volt scale. Boosted B+ is used for the high voltage side of the screen controls and the vert height and vert lin, as well as horizontal centering.

If the 13K resistor that is in series with the 47 ohm resistor has drifted high it will cause the HV to be low. You may have to raise the HOT cathode current a little. Maybe to 200ma. Lower is better, but it must stay under 210ma.

[timmy]

Originally Posted by Bill R

Use the HV probe to check the B+Boost, or a VTVM. Most DVOM meters do not measure a high enough voltage. I use an RCA Senior voltohmist VTVM on the 1500 volt scale. Boosted B+ is used for the high voltage side of the screen controls and the vert height and vert lin, as well as horizontal centering.

If the 13K resistor that is in series with the 47 ohm resistor has drifted high it will cause the HV to be low. You may have to raise the HOT cathode current a little. Maybe to 200ma. Lower is better, but it must stay under 210ma.

ok then the next step will be to check that 13k resistor and if its good then move on to the boosted voltage at the damper and ill use the hv probe. if the voltage is higher at the damper befor L30 but lower after then L30 may be bad so ill check the ohms on that .4 ohms. if this voltage is high then ill move to check caps in the yoke.

[Username1]

Timmy; Be aware that coils, and capacitors act on the signals coming through them so
to speak.... The raw DC off the damper is pulsed at 15K/cps. The voltage needs to be measured
at a point specified by the schematic. There is no way of knowing what is at the Damper
cathode, and no way of knowing what it's going to do to your test equipment....


Or if it's going to read it correctly....

My schematic is only that, I don't have a full service manual, and do not own a set like that,
or have recent experience on it.... SO be careful... Only use the HV probe.... ***

But There may be some validity in checking around there.... Because you say that you have
had retrace lines on the screen.... And I remember you saying something about how the
screen controls are set..... Do you always have retrace lines on the screen, no matter
what the brightness / contrast setting...?

Do you have a nice color picture that is for the most part accurate, and watchable...?

What company made the new flyback..... Do you remember OEM or Other....?


.

[timmy]

Originally Posted by Username1

Timmy; Be aware that coils, and capacitors act on the signals coming through them so
to speak.... The raw DC off the damper is pulsed at 15K/cps. The voltage needs to be measured
at a point specified by the schematic. There is no way of knowing what is at the Damper
cathode, and no way of knowing what it's going to do to your test equipment....


Or if it's going to read it correctly....

My schematic is only that, I don't have a full service manual, and do not own a set like that,
or have recent experience on it.... SO be careful... Only use the HV probe.... ***

But There may be some validity in checking around there.... Because you say that you have
had retrace lines on the screen.... And I remember you saying something about how the
screen controls are set..... Do you always have retrace lines on the screen, no matter
what the brightness / contrast setting...?

Do you have a nice color picture that is for the most part accurate, and watchable...?

What company made the new flyback..... Do you remember OEM or Other....?


.

well i will use the hv probe in that area to get an idea whats there. the flyback is a thordarson 273 and so was the one i took out. the color drives, rgb are fully counterclock, off and with them down like this i dont have the lines and i dont think its retrace but rather these color drives appear to be driven to hard by adjusting the right way in the setup mode maybe because of the lack of hv these drives need to be low to be even for the amout of hv present. set this way the picture is good but on white scenes its a different story or other scenes the colors will change alittle and or the pic will pull in alittle at one end. but is watchable. if i set the colors up the right way i have rgb lines across the screen and lots of blooming and brightness and contrast up or down makes no difference. right now with the drives down i have no lines and a decent picture but it is far from right and i dont want to leave it like this after spending so much time looking for this problem to just leave it alone now. the only thing i have to test a hv source like around the damper is the hv probe and i have been shocked many times, i dont like it but i try to be careful.

[Username1]

Don't worry about the shocks.... They're good for-ya- I got a good one once off some 17"
tube set I needed to adjust something and stuck my hand in there, and I watched a spark
jump from the picture tube to my hand on one side, and from the other side to the cabinet.
It cooked the skin and was a hard spot on both sides for months.... And dammit I'm still
here.... And stayed there for the rest of the day, and kept going back day after day...

Just remember to keep only one hand in there, and no path through you to ground....
So be careful what you wear, how you stand, and what you stand on...
No kneeling on cement floors...... Rubber mat maybe two if on cement.

It sure sounds like the picture tube does not have a proper bias setup... Overdrive
all the time.... Something is wrong there.... Have you gone over the voltages...?
At the picture tube pins...?

Lets check


Pin 3 I have 315V
pin 6 should be around 200V
pin 7 600V

What do you get....?

Anyone have good numbers for both sides of the pots on the screen controls...?

Anyone have ideas....? Worry about this now, or not....?

Added second picture with question Kine bias pot good...?

.

[timmy]

Originally Posted by Username1

Don't worry about the shocks.... They're good for-ya- I got a good one once off some 17"
tube set I needed to adjust something and stuck my hand in there, and I watched a spark
jump from the picture tube to my hand on one side, and from the other side to the cabinet.
It cooked the skin and was a hard spot on both sides for months.... And dammit I'm still
here.... And stayed there for the rest of the day, and kept going back day after day...

Just remember to keep only one hand in there, and no path through you to ground....
So be careful what you wear, how you stand, and what you stand on...
No kneeling on cement floors...... Rubber mat maybe two if on cement.

It sure sounds like the picture tube does not have a proper bias setup... Overdrive
all the time.... Something is wrong there.... Have you gone over the voltages...?
At the picture tube pins...?

Lets check


Pin 3 I have 315V
pin 6 should be around 200V
pin 7 600V

What do you get....?

Anyone have good numbers for both sides of the pots on the screen controls...?

Anyone have ideas....? Worry about this now, or not....?
.

ok solid colors-red-195v blue-186v green-193
white with colors-red-760v blue-757v green-759v
yelblue-280v yelgreen-276v yelred-245v this is the voltages when set up the right way but since lowering everything its less now. compared with the sams i have here the sams gives up to 680v to my 760v. i do believe i checked the kine pot as well but thats on my list again to check and the bias is counter also at this time.

[Username1]

I'm thinking your B+ Boost is too high.... It's showing up in the picture tube
bias circuit.... Problem is down around the coils and caps near efficiency coil,
all that goop around there... Resistors, caps, coils. Lets take a breather and let some
people with more time on this set chime in on what they have seen around
this area....

That sams have setup for the Horiz Efficiency coil.... Something we can use...?

.

[timmy]

Originally Posted by Username1

I'm thinking your B+ Boost is too high.... It's showing up in the picture tube
bias circuit.... Problem is down around the coils and caps near efficiency coil,
all that goop around there... Resistors, caps, coils. Lets take a breather and let some
people with more time on this set chime in on what they have seen around
this area....

That sams have setup for the Horiz Efficiency coil.... Something we can use...?

.

the sams i have says to use a 500ma meter a .47uf cap across meter a short across horiz oscill cathode coil pin 8 to ground ect adjust min current and not to exceed 210ma. it explains doing this and keeping track of hv current. so you think there could be a problem in the chroma board, hmmm i thought this may be a while ago but it remains to be seen.

[Username1]

No chroma board should only have color osc, demod's stuff like that, not B+ Boost
stuff on it....

If you feel that you can handle the efficiency coil adjustment I think you should at least
set up for it, and see if there is a working adjustment there.... Like some range, and
keeping under the current they recommend.....

Be very careful with the coils, you don't wanna do any damage with that stuff, It'll
be on the brittle side....

You may want to look at measuring the B+ Boost with that HV probe....
This has it marked, you can see it on the schematic near the 6BK4 tube.
They don't give a number. Sams might say something about B+ Boost,
check it out.... You can see how the B+ Boost goes right over to the pin 3's
of the screen adjust pots.... Your voltages look 100V too high, even at
cutoff.... I wonder what they would be if turned up a little.....

http://www.boxcarcabin.com/rca-ctc11-schematic.gif

If you can determine if the Boost is too high, then it's a matter of
testing each component to see if you can find it....

Is that focus rectifier good...? You said some resistor near the focus coil
was burnt up, was it R109 - 100K...?

Also you replaced the flyback with a Thordason same as was in it when you
got it, you have to begin thinking that two pins may be switched... You
may need to see how to check to be sure that that transformer was the
right way to begin with.....


.

[timmy]

Originally Posted by Username1

No chroma board should only have color osc, demod's stuff like that, not B+ Boost
stuff on it....

If you feel that you can handle the efficiency coil adjustment I think you should at least
set up for it, and see if there is a working adjustment there.... Like some range, and
keeping under the current they recommend.....

Be very careful with the coils, you don't wanna do any damage with that stuff, It'll
be on the brittle side....

You may want to look at measuring the B+ Boost with that HV probe....
This has it marked, you can see it on the schematic near the 6BK4 tube.
They don't give a number. Sams might say something about B+ Boost,
check it out.... You can see how the B+ Boost goes right over to the pin 3's
of the screen adjust pots.... Your voltages look 100V too high, even at
cutoff.... I wonder what they would be if turned up a little.....

http://www.boxcarcabin.com/rca-ctc11-schematic.gif

If you can determine if the Boost is too high, then it's a matter of
testing each component to see if you can find it....

Is that focus rectifier good...? You said some resistor near the focus coil
was burnt up, was it R109 - 100K...?

Also you replaced the flyback with a Thordason same as was in it when you
got it, you have to begin thinking that two pins may be switched... You
may need to see how to check to be sure that that transformer was the
right way to begin with.....


.

the resistor that is across 2 tabs on the focus coil its new and ok the original resistor was burned in 2 and dont know why but its been ok since the new one. the cathode current has a good swing as i can adjust it from around 180 all the way to over 210 ma . the focus rectifier is the 1v2 and is good along with any other resistors that go with it . i think there was a 1 meg and a low ohm resistor at the focus socket where its fed from the fly for the 1v2 heater. as for the fly being wired i went over the sams and the connections to make sure nothing else was wired wrong after finding the focus circuit wrong. if i turn the rgb drives up even al;ittle i get the lines and the blooming. i will have to get to that boost voltage to see what it is and if it is to high im not sure where to find the fault. what 2 pins are you saying may be switched ? i think the 1 meg is the focus wire to the crt.