Are these things I should consider bad

[Username1]

Tin Can;

Your jail bars are generated in the flyback area or Horiz Yoke area, not the low voltage power supply. Not even the caps in the low voltage power supply. The low voltage PS is designed to filter out 60hz, not so much the 15K spike traveling throughout your tv. And you will see it everywhere, but its made in one spot, and its pretty strong to get everywhere....Is the size of the horiz pulse off the driver transistor the right size and shape? This drives the horiz. output transistor.

Lets see, The biggest problem to solving or making progress in this, is that all of us don't have a schematic. So, at least you should post the horiz, section, From the Horiz Osc, to the high voltage wire to the picture tube.

Also, there are things called decoupling capacitors. They take the signal generated by a noisy item and run it to ground. They are not called that on any schematic for your tv, but they are there..... They are near the horiz output circuit, it will be a 30uf cap, or less and it runs the sharp point of the horiz pulse driving the horiz output transformer to ground.

If you remember I posted a picture with lots of red dots, find similar items near the horiz. output transformer on your schematic, and begin replacing them. Check for an open coil near it, or open winding leg on the flyback that goes to a cap to ground. You should check each winding on the flyback for posted resistance to see if one is open, or changed value.

[TinCanAlley]

Originally Posted by Username1

Tin Can;

Your jail bars are generated in the flyback area or Horiz Yoke area, not the low voltage power supply. Not even the caps in the low voltage power supply. The low voltage PS is designed to filter out 60hz, not so much the 15K spike traveling throughout your tv. And you will see it everywhere, but its made in one spot, and its pretty strong to get everywhere....Is the size of the horiz pulse off the driver transistor the right size and shape? This drives the horiz. output transistor.

Lets see, The biggest problem to solving or making progress in this, is that all of us don't have a schematic. So, at least you should post the horiz, section, From the Horiz Osc, to the high voltage wire to the picture tube.

Also, there are things called decoupling capacitors. They take the signal generated by a noisy item and run it to ground. They are not called that on any schematic for your tv, but they are there..... They are near the horiz output circuit, it will be a 30uf cap, or less and it runs the sharp point of the horiz pulse driving the horiz output transformer to ground.

If you remember I posted a picture with lots of red dots, find similar items near the horiz. output transformer on your schematic, and begin replacing them. Check for an open coil near it, or open winding leg on the flyback that goes to a cap to ground. You should check each winding on the flyback for posted resistance to see if one is open, or changed value.

Okay, the file was too large to upload, so I've copied portions of it into a word file and then created a new PDF. I'll attach it to this reply and hope it will work.

When I checked the horizontal pulse it was correct. I will double check it just to be 100% certain it is as should be (shape and voltage).

I'll try to locate that posting with the red dots.

So if I remove power, what else do I need to do to safely measure each winding of the flyback?

The 30uf cap you mention, is that would be an electrolytic? If so, I replaced all of them already. The only other I can find are the disc kind.

[TinCanAlley]

Originally Posted by Username1

Tin Can;

....Is the size of the horiz pulse off the driver transistor the right size and shape? This drives the horiz. output transistor.

I did the H Pulse and Sweep again. While they both look like they should, the sweep is supposed to be 120V according to Sams. But with a 50 V/Div, it takes up roughly 3.5 divisions. That would make it 175V. The pulse was on 20 V/Div and it takes up 3 divisions. That makes it 60V and Sams has it as 50V.

[TinCanAlley]

Originally Posted by Username1

Tin Can;

Also, there are things called decoupling capacitors. They take the signal generated by a noisy item and run it to ground. They are not called that on any schematic for your tv, but they are there..... They are near the horiz output circuit, it will be a 30uf cap, or less and it runs the sharp point of the horiz pulse driving the horiz output transformer to ground.

I found the cap running off the horizontal output transformer. It's a 47uf and was replaced.

[TinCanAlley]

I'm glad I started looking at the caps in the horizontal area. Seems when I recapped I put the 10uf 50V cap in backwards. It was my fault as I didn't have a radial and didn't want to order just for one cap. I went through my supply and found some of the audio grade Nichicon. I thought I was installing a KW series which has gold band for negative, but I put in an FW which has black for negative so the gold casing threw me off and I installed the negative based on the gold side. Odd it didn't explode, though.

Anyway, the cap has been replaced and the backwards one not reads as 5uf instead of 10uf. Don't know what it was doing to the set (if anything), but it sure didn't have anything to do with the jail bars as they're still there.

I also thought I put in the 47uf on the horizontal output transformer as it had + on ground, but looking over the schematics and pictures I took before the recap, it is supposed to be that way. Looking over all other caps while I was under there shows those are all installed correctly.

[jr_tech]

I don't see the HV supply on the schematic... which page is it on?

jr

[TinCanAlley]

Originally Posted by jr_tech

I don't see the HV supply on the schematic... which page is it on?

jr

Do you mean the flyback (T207)? If so, it's on the second page bottom center. If that's not it, I'm not sure as I thought it was the HV supply.

[jr_tech]

Thanks! I found it.
jr

[Username1]

Good morning;

Ok, lets begin with your scope. It needs to be checked for some level of calibration. This can be done by you at home for a very little amount of money. You need to get a series of 9v batteries, hook them up to give you 18v, 56v, then check the voltages with a volt meter, write it down. Then use your scope, - lead to ground on scope, hit the + battery with your scope probe. If you have to make a circuit with a momentary contact switch and hook up your wires and watch your scope. You should be able to verify your scope is reading the proper voltage range this way.

You mentioned two spots where your voltages might not be correct. These need to be investigated. This is the way you will find this problem.

As an example, lets look at a audio amplifier, one with a pilot light on it. If you run it at some mid volume, the sound will be clear. If you turn it up to saturation, especially bass, it will distort, and in most cases the pilot light will begin to dim with the bass notes. Your jail bars are coming from something that is allowed to saturate, something in the horiz, output area, and it is ringing, and you see it everywhere in the tv, just like in the audio amplifier saturation blinking the pilot light. If your set were working correctly, this would be filtered out, but a spike it too large and showing up in places it should not. While the jail bars may show up in many places, it can only be fixed by removing it at the source, the horiz section of the tv.

In these sections in the pictures I am posting, you need to be sure all of the voltages, wave forms, are correct. There will be some clue, voltage wrong, wave shape wrong, open coil, changed resistor, something. Start with the Horiz driver, then go to horiz output, then flyback. Focus on the items in the three pictures I am uploading. If the voltages or wave shapes, sizes of wave shapes, p-p voltages are wrong, do not go on to the next stage. Check everything listed, voltages, wave shapes and sizes peak-to peak dc offset if its there. If the osc, driver section (left picture) has something not right, stay there until it is.... Do not go on to the center picture items.

Start with the left picture, then center, then right.

[TinCanAlley]

Originally Posted by Username1

Good morning;

Ok, lets begin with your scope. It needs to be checked for some level of calibration. This can be done by you at home for a very little amount of money. You need to get a series of 9v batteries, hook them up to give you 18v, 56v, then check the voltages with a volt meter, write it down. Then use your scope, - lead to ground on scope, hit the + battery with your scope probe. If you have to make a circuit with a momentary contact switch and hook up your wires and watch your scope. You should be able to verify your scope is reading the proper voltage range this way.

You mentioned two spots where your voltages might not be correct. These need to be investigated. This is the way you will find this problem.

As an example, lets look at a audio amplifier, one with a pilot light on it. If you run it at some mid volume, the sound will be clear. If you turn it up to saturation, especially bass, it will distort, and in most cases the pilot light will begin to dim with the bass notes. Your jail bars are coming from something that is allowed to saturate, something in the horiz, output area, and it is ringing, and you see it everywhere in the tv, just like in the audio amplifier saturation blinking the pilot light. If your set were working correctly, this would be filtered out, but a spike it too large and showing up in places it should not. While the jail bars may show up in many places, it can only be fixed by removing it at the source, the horiz section of the tv.

In these sections in the pictures I am posting, you need to be sure all of the voltages, wave forms, are correct. There will be some clue, voltage wrong, wave shape wrong, open coil, changed resistor, something. Start with the Horiz driver, then go to horiz output, then flyback. Focus on the items in the three pictures I am uploading. If the voltages or wave shapes, sizes of wave shapes, p-p voltages are wrong, do not go on to the next stage. Check everything listed, voltages, wave shapes and sizes peak-to peak dc offset if its there. If the osc, driver section (left picture) has something not right, stay there until it is.... Do not go on to the center picture items.

Start with the left picture, then center, then right.

The scope was professionally calibrated when I got it a couple of weeks ago. I know it reads the same voltage I get with my DMM.

Tomorrow I'll start on your list. I know it's not the horizontal driver as I replaced the module with a newer, NOS board and have the same problem. That module has the wave shaper, horizontal AFC, OSC and driver. The module isn't the source, but it could be affected by it.

[TinCanAlley]

I do have a question, though. On the schematics for the H. Sweep it says that point is T5 and is 63.7V. However, the waveform shown for that point says it's 120VPP. How is that? How can you get a 120V PP with a driving voltage of 63.7V?

This is the point I had a 160V PP. That will be my first recheck tomorrow morning. Today is a complete mess and no time for the poor set.

[N2IXK]

Originally Posted by TinCanAlley

I do have a question, though. On the schematics for the H. Sweep it says that point is T5 and is 63.7V. However, the waveform shown for that point says it's 120VPP. How is that? How can you get a 120V PP with a driving voltage of 63.7V?.

The 63.7V is the DC voltage you should read if you measure that point with a DMM. The 120 Vpp is the amplitude of the AC waveform present.

The waveform looks to be roughly 50% duty cycle (pretty close to a square wave), and if it oscillates from 0 to 120V peak, the average voltage would be around 50% of 120V, or somewhere around 60V. 63.7 sounds like a perfectly reasonable reading to expect on a DC voltmeter.

Did you ever sit through that scope training course? Real basic stuff like this really needs to be understood before you can really hope to be able to repair a TV except by sheer luck...

[TinCanAlley]

Originally Posted by N2IXK

The 63.7V is the DC voltage you should read if you measure that point with a DMM. The 120 Vpp is the amplitude of the AC waveform present.

The waveform looks to be roughly 50% duty cycle (pretty close to a square wave), and if it oscillates from 0 to 120V peak, the average voltage would be around 50% of 120V, or somewhere around 60V. 63.7 sounds like a perfectly reasonable reading to expect on a DC voltmeter.

Did you ever sit through that scope training course? Real basic stuff like this really needs to be understood before you can really hope to be able to repair a TV except by sheer luck...

Yep, I watched it. I was pretty much on the right track and just needed a few visual instructions to understand the rest. I can now do all the basics and am learning more each day.

[Username1]

The test point may contain information that can be interpeted 2 different ways. With a scope, you will see the entire wave, peak to peak. Your volt meter depending on design will read whatever it is designed to read, some will read and store peak, some will read average, and most will read some type of R.M.S. this is a area under the curve calculus derived average voltage. The schematic often details how all readings are taken, and in some cases even details the type and model instrument used, (or equiv.) is often written. Your RMS voltage will depend on the quality of your meter, and the old expensive ones did say what frequency you can use it and expect a certain level of accuracy. I don't know what new ones say in the instructions...

It is important to be sure your test equipment is reading correctly, or you will be chasing something that does not exist. A calibrated ebay piece of equipment means squat unless you do a little checking to be sure it really is what it is....

If tp5 is not reading correctly, your problem may be right there, everything very near that point needs to be checked.

Funny thing about man made stuff.... Sometimes one model of something all have the same problem. So don't overlook something just because you got a replacement somewhere.... Go by what good troubleshooting skills are taking you towards.

[TinCanAlley]

Originally Posted by Username1

The test point may contain information that can be interpeted 2 different ways. With a scope, you will see the entire wave, peak to peak. Your volt meter depending on design will read whatever it is designed to read, some will read and store peak, some will read average, and most will read some type of R.M.S. this is a area under the curve calculus derived average voltage. The schematic often details how all readings are taken, and in some cases even details the type and model instrument used, (or equiv.) is often written. Your RMS voltage will depend on the quality of your meter, and the old expensive ones did say what frequency you can use it and expect a certain level of accuracy. I don't know what new ones say in the instructions...

It is important to be sure your test equipment is reading correctly, or you will be chasing something that does not exist. A calibrated ebay piece of equipment means squat unless you do a little checking to be sure it really is what it is....

If tp5 is not reading correctly, your problem may be right there, everything very near that point needs to be checked.

Funny thing about man made stuff.... Sometimes one model of something all have the same problem. So don't overlook something just because you got a replacement somewhere.... Go by what good troubleshooting skills are taking you towards.

The scope was calibrated by Teletek using N.I.S.T. standards and certified by them. I have a certificate of calibration. I also get a free calibration within one year, but they're up north and I don't know how practical it would be shipping to and from.

Okay, so how about this. I have tested it on DC and it reads correctly. For AC, can I check an outlet? I have a meter that plugs into the outlet and shows the voltage. It has an outlet to plug things in and measure wattage, etc. Can I use the scope to see if it reads the same AC voltage as the meter? Would also be interesting to see how noisy the AC line is.