More screen anomalies

[Username1]

If you replaced the Horiz osc board with a known good one, move on, If you have a known good voltage divider and want to replace it, do so, then move on. With parts of the Horiz. circuit out of the way, move on over to the flyback, and parts that may be mounted near it.

You will have to check items on the chassis that are part of the horiz. that are not on the module.

When you say diodes had their leads cut then resoldered, did they cut one side, then resolder, or cut both sides...? Both sides may mean they chose to replace the part from on top of the board, I have seen that before, cutting one side may just be to test it with a vom.

[TinCanAlley]

Originally Posted by Username1

If you replaced the Horiz osc board with a known good one, move on, If you have a known good voltage divider and want to replace it, do so, then move on. With parts of the Horiz. circuit out of the way, move on over to the flyback, and parts that may be mounted near it.

You will have to check items on the chassis that are part of the horiz. that are not on the module.

When you say diodes had their leads cut then resoldered, did they cut one side, then resolder, or cut both sides...? Both sides may mean they chose to replace the part from on top of the board, I have seen that before, cutting one side may just be to test it with a vom.

They cut only one lead and resoldered. I'm assuming they were testing, found nothing and soldered the leg back. No replacements were done.

Okay, just purchased a Tektronix 465M Oscilloscope, NIST-certified, Guaranteed & NIST calibrated off ebay. Hopefully it will be here around this time next week.

So I guess I'll just change the divider and let her be until the scope arrives. Now you said I need two probes? If so, I'll order another of the one I already have.

[Username1]

Originally Posted by TinCanAlley

They cut only one lead and resoldered. I'm assuming they were testing, found nothing and soldered the leg back. No replacements were done.

Okay, just purchased a Tektronix 465M Oscilloscope, NIST-certified, Guaranteed & NIST calibrated off ebay. Hopefully it will be here around this time next week.

So I guess I'll just change the divider and let her be until the scope arrives. Now you said I need two probes? If so, I'll order another of the one I already have.

A 465M is a really good scope, one of my favorites, Calibration certified means you can get your money back if you decide to sell one day. I bet it was expensive, be sure you get the papers. Be sure to get probes so you can use it when you get it.

2 probes are an option, your scope will get a trigger signal off whatever you apply to one channel, the second probe is just in case you need to use a separate trigger source, good idea to have for some needs. Be sure you get ones with 1x 10x options and trimmer adjustment for capacitance, this will match impedance properly. Your scope has a square wave test point on its front, attach the probe, and adjust the trimmer to get a nice square wave with no overshoot, or loading (rounding of the square edges).

Just for the heck of it, when you just set that tv up to run as normal, and wack it a few times does anything happen to either the sound or picture that would indicate any loose connections, since this is a module set, any indication of disturbance while hitting it may mean you have bad plugs, or connectors on the boards....?

[TinCanAlley]

Originally Posted by Username1

A 465M is a really good scope, one of my favorites, Calibration certified means you can get your money back if you decide to sell one day. I bet it was expensive, be sure you get the papers. Be sure to get probes so you can use it when you get it.

2 probes are an option, your scope will get a trigger signal off whatever you apply to one channel, the second probe is just in case you need to use a separate trigger source, good idea to have for some needs. Be sure you get ones with 1x 10x options and trimmer adjustment for capacitance, this will match impedance properly. Your scope has a square wave test point on its front, attach the probe, and adjust the trimmer to get a nice square wave with no overshoot, or loading (rounding of the square edges).

Just for the heck of it, when you just set that tv up to run as normal, and wack it a few times does anything happen to either the sound or picture that would indicate any loose connections, since this is a module set, any indication of disturbance while hitting it may mean you have bad plugs, or connectors on the boards....?

I have one 10x probe already (just purchased it a couple of weeks ago) and have order a second one. They do have the trimmer adjustment, so I think all will be good when the scope arrives.

The scope is supposed to come with a calibration certificate. I'll probably keep it afterwards and start scoping anything and everything. I know if I get rid of it, I'll need it.

I guess I can use something to tap around on the chassis and modules to see if there's something loose (think I have a drum stick around somewhere). Whacking the set does no good as it's a solid cabinet and only serves to sting my hand.

[TinCanAlley]

Originally Posted by Username1

2 probes are an option, your scope will get a trigger signal off whatever you apply to one channel, the second probe is just in case you need to use a separate trigger source, good idea to have for some needs. Be sure you get ones with 1x 10x options and trimmer adjustment for capacitance, this will match impedance properly. Your scope has a square wave test point on its front, attach the probe, and adjust the trimmer to get a nice square wave with no overshoot, or loading (rounding of the square edges).

I do have a question about test points. In the Sams it shows a test point between one leg of the vertical transistor and one leg of the horizontal blanking transistor. Seems the two legs are tied together and then a resistor goes to ground from that solder point. Now the test point is right at that junction and it can only be reached from the bottom of the chassis. Is it important to get that point or can I just connect the probe on the top side directly to the leg of the blanker transistor? Either way it's on the same end of the resistor, so that's not an issue. It's just not at the solder point of the two legs.

I hope that makes sense.

[Findm-Keepm]

One question that doesn't seem to be answered in the previous posts - what is your signal source? Is it a cheapo DVD player, or some sort of RF Modulator? I can get jailbars on any set, tube, solid state, B/W or Color with my cheapo Conar bar-dot generator, so it could be signal source, plain and simple.

Cheers,

[TinCanAlley]

Originally Posted by Findm-Keepm

One question that doesn't seem to be answered in the previous posts - what is your signal source? Is it a cheapo DVD player, or some sort of RF Modulator? I can get jailbars on any set, tube, solid state, B/W or Color with my cheapo Conar bar-dot generator, so it could be signal source, plain and simple.

Cheers,

The jail bars are there with two different RF modulators, two VCRs and one '87 laserdisc player with built-in RF. Now unless the bars could be caused by the AC line, I think it's the set.

Is there something else I can try? I wish there were a broadcast signal I could tune into. I do have a Blonder Tongue Agile Processor. Maybe I can get it to broadcast a signal on a VHF channel and use the good ole rabbit ears.

[Eric H]

If you still haven't changed the Focus Divider I would start with that.

If it's arcing then it's defective, anything defective in the HV circuits has the potential to put interference on the screen, so start with that then look elsewhere if that doesn't help.

[TinCanAlley]

Originally Posted by Eric H

If you still haven't changed the Focus Divider I would start with that.

If it's arcing then it's defective, anything defective in the HV circuits has the potential to put interference on the screen, so start with that then look elsewhere if that doesn't help.

That is on my list for tomorrow. You wouldn't happen to know how the pink lead is connected in the anode cap, do you? It looks like it is just pushed into the cap through the hole next to the anode lead.

[Eric H]

Originally Posted by TinCanAlley

That is on my list for tomorrow. You wouldn't happen to know how the pink lead is connected in the anode cap, do you? It looks like it is just pushed into the cap through the hole next to the anode lead.

Is there a screw in the center of the cap on the inside? If so you probably just loosen that screw and pull out the old wire, reverse process to install.

[TinCanAlley]

Originally Posted by Eric H

Is there a screw in the center of the cap on the inside? If so you probably just loosen that screw and pull out the old wire, reverse process to install.

I haven't removed the cap yet, but if I look closely, the pink lead from the divider isn't all the way forward like the anode. I'm attaching a pic. It's the best one I have of it clean. I can find plenty of pics when it was dirty and you couldn't see through it.

I guess I'll know tomorrow when I ground it and remove it.

[zeno]

Originally Posted by TinCanAlley

I haven't removed the cap yet, but if I look closely, the pink lead from the divider isn't all the way forward like the anode. I'm attaching a pic. It's the best one I have of it clean. I can find plenty of pics when it was dirty and you couldn't see through it.

I guess I'll know tomorrow when I ground it and remove it.

Thats the old style connector. If you have a NOS tripler use
the larger brown one off it. Usually they have a small phillips
clamping the wires down. Thats IF it has 2 holes !

The 103-193 came in at least 2 styles. Fat grey ones & later
plain old black. Dont worry about them unless they have been
changed.

Grounds I assume you checked the terminal strip grounds.

When u attack the jail bars. I think you have a generator.
Hook it up & if it has a staircase pattern ( stripes going from
white to black across the screen) look at the video with the
scope. You will see two lines of a staircase. This shows you
how the levels relate to the pattern. Go to the IF output
( point 38 or C1 on Sams)
first at 7875 cycles & you will see 2 lines of the pix complete
with staircases at apx 1.5 V. This is raw unblanked video
sync & all. Next put the generator on blank raster.
If the bars have been introduced at that point you will
see 10 little bumps, if not nothing but a line between the
horz pulses. Work your way to the right Q203 B, Q203 C,
Q204 B, Q204 E, etc until you see them. The pattern will
get bigger & be blanked but you will see two lines.

One other thing. Odds are this set ran for years with too
much HV. Check the ABL that is off the tripler at R362.
CR223, R359, 360, Q201 etc.

While you are at it get an old book or look on internet for
what the things on the scope are. Sync pulses,
burst, back porch, blacker than black etc. It will help you
a lot.

73 fer now Zeno

[jr_tech]

Originally Posted by TinCanAlley

That is on my list for tomorrow. You wouldn't happen to know how the pink lead is connected in the anode cap, do you? It looks like it is just pushed into the cap through the hole next to the anode lead.

I have never messed with anything that new, but in all that I have seen the clip is soldered to the HV lead. Grease up the lead where it enters the cup and push it further into the cup, while gently pulling the clip out of the cup. The clip should come out of the cup so that you can unsolder the wire and pull it out. Push the new wire in and solder to the clip, then pull it back so that the clip is seated in the cup as before.

jr

[TinCanAlley]

Originally Posted by Eric H

If you still haven't changed the Focus Divider I would start with that.

If it's arcing then it's defective, anything defective in the HV circuits has the potential to put interference on the screen, so start with that then look elsewhere if that doesn't help.

I changed the focus divider, and while it didn't help with the bars or moire, it did give me better focus control and a sharper image.

The wire was just press fit into the anode cap. I'm attaching a couple pics of the wire removed and the cap. There was no crimping or set screw. The farther you insert the wire, the tighter it gets.

[Username1]

From Zeno's post;
"first at 7875 cycles & you will see 2 lines of the pix complete
with staircases at apx 1.5 V. This is raw unblanked video
sync & all. Next put the generator on blank raster.
If the bars have been introduced at that point you will
see 10 little bumps, if not nothing but a line between the
horz pulses.. Work your way to the right Q203 B, Q203 C,
Q204 B, Q204 E, etc until you see them. The pattern will
get bigger & be blanked but you will see two lines."

Your best bet, starting fresh as you are, is to look at these items as he stated, but your bars will be easier to spot as he said with blank raster however you get it. But pay attention to the stairs, or whatever you have, then go to blank, and you will see the part of the trace that makes up the tv picture, the bars will be in that space.

Can you upload that schematic to some free ftp spot and post a link to it, then just delete it after those interested in this thread get a copy....?