ctc12 clone beam current

[Bill R]

Originally Posted by DaveWM

blue should go to focus coil(w/100k mounted to focus coil),1.5 meg (part of shunt reg circuit),10k(part of boost supply circuit),.12 cap,bottom winding of fly.

BOTTOM WINDING OF FLY NEEDS TO BE CONFIRMED

The other end of the .12 cap goes to a tap on the efficency coil. That all sounds correct.

If Boost is low it is because your HV is low. Since you had 30KV with the regulator cap off I would assume it is capable of producing the 24KV needed under load. Low HV could be caused by insufficent drive from the H out tube, or from excessive load on the HV section. For now the screen voltages on CRT pins 3 7 and 11 may be close. Looks like Boost is 750 to 800 volts. The B+ should be 395 volts. So the screen voltages should be between 400 and 800 volts. Look at the CRT cathode voltages. They should all be close to 300 volts. These are controlled by the kine bias and drive controls. Double check the kine bias pot, and the resistors on either side of the kine bias control. The video out tube and associated circuit can also cause retrace lines and blooming because it can cause the CRT to draw excessive beam current. I would verify the componants in the 12BY7 video output circuit. There are several high wattage resistors between the plate and the Kine bias control and you could have some leaky capacitors. Oh yeah, do check the video output tube.
In a normal gray scale setup you start with Kine bias all the way down and the drive controls all the way up. You adjust the screen controls for a barely visible line. If one color does not make a line you leave that screen control up and increase the kine bias to produce a barely visible line, then bring the other colors screen controls up to match. With a normal brightness Black and white picture on the screen adjust the drive controls to eliminate color shading. One of the drives will usually be at max and you reduce the other one to eliminate shading.
If the CRT current is high and it is loading the HV section the Regulator current will be low. Regulator current should be between 85 and 140 milliamps.
I am a little curious about the screen voltage not going below 584 volts. Maybe the CRT is conducting to hard due to improper bias on the cathodes. Hmmm.

[Electronic M]

Originally Posted by Bill R

Regulator current should be between 85 and 140 milliamps.

Don't you mean microamps (uA)? The regulator works by loading the HV so if it is drawing 140mA from a 25kV source then it would be pulling 3500W through the flyback which is impossible.

[miniman82]

Should be able to run about 100 roundies with that.

[timmy]

the only blue wire on this flyback is soldered from one end of the 47meg and runs up to the vert board it shows this in both sams and the rca schematic. i think maybe the problem is different color wires were used for the clone and rca. looking at the coil of the fly the bottom lead #1 goes to the #2 of the f coil and the top lead #2 goes to #1 of the f coil and on the 100k resistor, also on that tap is a red wire and that goes under the chassis to the 1.5meg and on to the .12 cap. the other blue wire is from the yoke and that is in the correct place. weather top or bottom wire the numbers on the fly are right with the numbers on the f coil . at least what both rca and sams shows as to what number terminals go where from fly to f coil.

[timmy]

either way its all in the right place. the .12 cap i could not get a .12 so moyer gave me 2 different caps to make up this 12 , and i also had changed the .15 cap maybe these are bad. my problem is i dont want to switch a wire from one place to another by placing what appears to be boost on one terminal and putting it on another when both schematics show it is correct now. i just want to be sure as to the wires with colors for the crt cathodes because i will check this with the color drives at minimum .the last time i check if im right with the cathodes , the yellow wires, they ranged from 280v 276v 245v.

[DaveWM]

you need to know if the fly is wired properly. that means you need to determine if the blue lead of the yoke is connected to the bottom of the fly winding.

did you confirm the bottom of the fly yet?

[timmy]

[QUOTE=DaveWM;3124016]you need to know if the fly is wired properly. that means you need to determine if the blue lead of the yoke is connected to the bottom of the fly winding.

did you confirm the bottom of the fly yet?[/QUOTE ok what shows on the sams is that the blue wire from the yoke is at the bottom of the fly interconnected with a red under the chassis which comes up and is on terminal # 2 labeled on the fly so it is correct.

[Username1]

Timmy - Do you still have the flyback that you removed from this tv....?

.

[timmy]

nol i dont have it i sold it to someone and it was fine and worked ok.

[Bill R]

Yes I mean microamps. Sorry bout that.

[timmy]

i did already check a few resistors around the 12by7 video output tube only to find they were ok. i also tried another good 12by7.

[timmy]

Originally Posted by Bill R

The other end of the .12 cap goes to a tap on the efficency coil. That all sounds correct.

If Boost is low it is because your HV is low. Since you had 30KV with the regulator cap off I would assume it is capable of producing the 24KV needed under load. Low HV could be caused by insufficent drive from the H out tube, or from excessive load on the HV section. For now the screen voltages on CRT pins 3 7 and 11 may be close. Looks like Boost is 750 to 800 volts. The B+ should be 395 volts. So the screen voltages should be between 400 and 800 volts. Look at the CRT cathode voltages. They should all be close to 300 volts. These are controlled by the kine bias and drive controls. Double check the kine bias pot, and the resistors on either side of the kine bias control. The video out tube and associated circuit can also cause retrace lines and blooming because it can cause the CRT to draw excessive beam current. I would verify the componants in the 12BY7 video output circuit. There are several high wattage resistors between the plate and the Kine bias control and you could have some leaky capacitors. Oh yeah, do check the video output tube.
In a normal gray scale setup you start with Kine bias all the way down and the drive controls all the way up. You adjust the screen controls for a barely visible line. If one color does not make a line you leave that screen control up and increase the kine bias to produce a barely visible line, then bring the other colors screen controls up to match. With a normal brightness Black and white picture on the screen adjust the drive controls to eliminate color shading. One of the drives will usually be at max and you reduce the other one to eliminate shading.
If the CRT current is high and it is loading the HV section the Regulator current will be low. Regulator current should be between 85 and 140 milliamps.
I am a little curious about the screen voltage not going below 584 volts. Maybe the CRT is conducting to hard due to improper bias on the cathodes. Hmmm.

the way you outline how to do the grey scale is correct and it is also explained the same way in my sams here and doing it this way does not work because having to use the bias pot for a color to show and doing it by the book , this is when blooming and the rgb lines occur and its just a mess, and the hv drops even more if i set it up the right way.

[timmy]

ok here are voltages with the crt cap plug on bright up, y blue 220v y red 220v y green 237v
w blue 557v w red 557v w green 558v
blue 192 v red 194 v green 190 v
with the other drives , blue and green counterclock the voltages raise up alittle. seems as thought that 557-558v is high with the color pots at minimum. i had done this voltage test with the crt cap off befor but tried it this time with the cap on.

[timmy]

the voltage off the diodes in the PS is 401 volts and i pulled the hot and the damper and there is 410 volts at what looks like pins 2 and 8. and 281 volts at either the last or first pin. if this is any help. i really think its odd that there is never any voltage in the crt just after turning it off anode short to ground there is zero even just turning it off.

[DaveWM]

You don't seem to understand what I am saying

did you EVER confirm the bottom winding of the fly (please don't reference the sams again). I told you how to do this and squirrel boy expanded on it.

the blue wire from the yoke must be connected to the bottom winding of the fly.