Hello All,
It was working again and then as I got the sound perfect POOF! It's blowing fuse after fuse again. I have the width coil in there too and as high as I can turn the width when it is working, the picture is narrow. The flyback looks fine. The 1B3 tests good. All the tubes test good. What's going on? I can't understand it. One minute it works and the next minute it's popping fuses.

Dave...

Well.......I forgot where you were with this thing in the other article that was so long, but here are things to look for: When is it blowing fuses? Do they blow when you turn the set on or while it is operating? If they blow when you turn the set on, this is usually a fairly simple problem. The fuse is too small for the start-up surge, especially when all the tubes are warmed up and the electrolytics can put put their full load on the fuse. Seeing as I forgot what this fuse goes to, I'm assuming that it fuses the entire set or at least the power supply, or maybe you said the HV supply. I forgot. Simply increase the amperage of the fuse by either a half number or a full number, and use slow-blow fuses. If the diagram calls for a certain number, though, don't go increasing numbers by more than half or one at the most. One is fairly safe, but still, the fuse protects other devices, so don't go out of bounds too much.

If the fuse blows while the set is on, did you replace all the condensers? I know this sounds redundant of what I always say, but condensers are probably the worst trouble you'll find in any antique electronic equipment. They leak and throw off values, and they open up (only sometimes). They do lovely little spontaneous arcing that you have no clue about because it only happens for a moment, throws things off, ruins a part, or blows a fuse, and the arcing often cannot be recreated with your multi-meter, as it uses very low voltage. The only way to properly test condensers if you intend on reusing them is with a high voltage tester. You can find Solar capacitor testers on eBay, which are awesome little pieces of equipment with the 6E5 magic eye tubes. You can also build a simple capacitor tester that doesn't test capacitance, but tests for leakage using 100 volts or more, which will cause arcing if arcing does happen. Simply build either an AC/DC 110 volt power supply (use a solid state rectifier or a 117Z6 tube and some filter condensers, and put some 50 to 100K resistors in series with each supply lead to protect the supply againts shorts......connect supply in series with your multi-meter set to voltage appropriate to that being used, and connect condenser in question in series with the former two), or you can build an AC power supply (using the above techniques except with an AC transformer of 200 to 350 volts output and an appropriate 5Y3 or 80 rectifier, etc.).

Other causes could be arcing at a tube socket or a faulty wire or wires that are too close, yoke to aquadag, high voltage to something, Lord knows what. With televisions, cleanliness is essential. The carbon and material that collects in mere dust can cause catastrophic disaster. The picture tube anode lead must be incredibly clean. If the black residue cannot be removed from the lead, put shrink wrap around the lead for its entire length. The HV rectifier socket and its surroundings must be incredibly clean as well. Make sure that all cages and covers do not touch any leads or come close to any leads.

You could have a transformer that is arcing. You name it. If you see black greasy dirt film on the underside of the chassis, this needs to be cleaned away from contacts. This can cause all sorts of trouble. Use a Q-tip and alcohol or acetone. Be careful. Don't go nuts, but if you suspect that the grime is causing trouble, then you need to clean it up. Be critical of high voltage terminals and leads.

Of course you said that you tested the tubes. Tap them and test each element against the others. Make sure they don't short out occasionally. I'm working on a radio for a friend right now, and the 6F6 tubes are incredibly fine. They have the nicest emission. Still, when I turn the radio upside-down to adjust the circuitry, one of them has a bit of debris that shorts out the screen grid and causes the screen grid resistor to overheat. Now, this only happens once in a great while for a moment, so unless you pay attention, you'd never know what was causing the smoke. Tap the tubes and turn the radio right-side-up, and all is well all the time, well, except for once there was an arc that jumped in one of the tubes when the volume was turned up really loud. Turn it upside-down, and you don't know what will happen.

Don't let anything go unlooked. Sad to say, anything can cause the trouble. Sometimes it takes months of patients and sometimes leaving the set on the back burner, to find a qwerky little intermittent problem.

Good luck!

Thomas

Tom,
I had thought that the wires on the yoke may be too long and getting too close to the picture tube or the HV line. I see no evidence of burning. Everything looks almost like new. The chassis is shiny.
The 8.2K resistor was open and so was a 47K ohm resistor. This fuse is just for the HV section allowing B+ to get to pin 5 on the 6AX4 damper and to pin 4 on the 6DQ 6, through a couple of resistors. The rest of the set is powered up by this B+ even if the fuse is open.

Dave...
:Well.......I forgot where you were with this thing in the other article that was so long, but here are things to look for: When is it blowing fuses? Do they blow when you turn the set on or while it is operating? If they blow when you turn the set on, this is usually a fairly simple problem. The fuse is too small for the start-up surge, especially when all the tubes are warmed up and the electrolytics can put put their full load on the fuse. Seeing as I forgot what this fuse goes to, I'm assuming that it fuses the entire set or at least the power supply, or maybe you said the HV supply. I forgot. Simply increase the amperage of the fuse by either a half number or a full number, and use slow-blow fuses. If the diagram calls for a certain number, though, don't go increasing numbers by more than half or one at the most. One is fairly safe, but still, the fuse protects other devices, so don't go out of bounds too much.
:
:If the fuse blows while the set is on, did you replace all the condensers? I know this sounds redundant of what I always say, but condensers are probably the worst trouble you'll find in any antique electronic equipment. They leak and throw off values, and they open up (only sometimes). They do lovely little spontaneous arcing that you have no clue about because it only happens for a moment, throws things off, ruins a part, or blows a fuse, and the arcing often cannot be recreated with your multi-meter, as it uses very low voltage. The only way to properly test condensers if you intend on reusing them is with a high voltage tester. You can find Solar capacitor testers on eBay, which are awesome little pieces of equipment with the 6E5 magic eye tubes. You can also build a simple capacitor tester that doesn't test capacitance, but tests for leakage using 100 volts or more, which will cause arcing if arcing does happen. Simply build either an AC/DC 110 volt power supply (use a solid state rectifier or a 117Z6 tube and some filter condensers, and put some 50 to 100K resistors in series with each supply lead to protect the supply againts shorts......connect supply in series with your multi-meter set to voltage appropriate to that being used, and connect condenser in question in series with the former two), or you can build an AC power supply (using the above techniques except with an AC transformer of 200 to 350 volts output and an appropriate 5Y3 or 80 rectifier, etc.).
:
:Other causes could be arcing at a tube socket or a faulty wire or wires that are too close, yoke to aquadag, high voltage to something, Lord knows what. With televisions, cleanliness is essential. The carbon and material that collects in mere dust can cause catastrophic disaster. The picture tube anode lead must be incredibly clean. If the black residue cannot be removed from the lead, put shrink wrap around the lead for its entire length. The HV rectifier socket and its surroundings must be incredibly clean as well. Make sure that all cages and covers do not touch any leads or come close to any leads.
:
:You could have a transformer that is arcing. You name it. If you see black greasy dirt film on the underside of the chassis, this needs to be cleaned away from contacts. This can cause all sorts of trouble. Use a Q-tip and alcohol or acetone. Be careful. Don't go nuts, but if you suspect that the grime is causing trouble, then you need to clean it up. Be critical of high voltage terminals and leads.
:
:Of course you said that you tested the tubes. Tap them and test each element against the others. Make sure they don't short out occasionally. I'm working on a radio for a friend right now, and the 6F6 tubes are incredibly fine. They have the nicest emission. Still, when I turn the radio upside-down to adjust the circuitry, one of them has a bit of debris that shorts out the screen grid and causes the screen grid resistor to overheat. Now, this only happens once in a great while for a moment, so unless you pay attention, you'd never know what was causing the smoke. Tap the tubes and turn the radio right-side-up, and all is well all the time, well, except for once there was an arc that jumped in one of the tubes when the volume was turned up really loud. Turn it upside-down, and you don't know what will happen.
:
:Don't let anything go unlooked. Sad to say, anything can cause the trouble. Sometimes it takes months of patients and sometimes leaving the set on the back burner, to find a qwerky little intermittent problem.
:
:Good luck!
:
:Thomas

Tom,
And yes, every paper and filter capacitor was replaced. Every single one. There are zero paper and zero old filter capacitors left. All of those capacitors are brand new.
The fuse blows as its warming up. It calls for a .200 amp fuse. I used .250 amp slow blow fuses. Poof! (it snaps inside) as it's warming up. Then all the filaments get brighter.
I think something with burn if I put a 1/2 amp fuse in there.

Dave...
:Well.......I forgot where you were with this thing in the other article that was so long, but here are things to look for: When is it blowing fuses? Do they blow when you turn the set on or while it is operating? If they blow when you turn the set on, this is usually a fairly simple problem. The fuse is too small for the start-up surge, especially when all the tubes are warmed up and the electrolytics can put put their full load on the fuse. Seeing as I forgot what this fuse goes to, I'm assuming that it fuses the entire set or at least the power supply, or maybe you said the HV supply. I forgot. Simply increase the amperage of the fuse by either a half number or a full number, and use slow-blow fuses. If the diagram calls for a certain number, though, don't go increasing numbers by more than half or one at the most. One is fairly safe, but still, the fuse protects other devices, so don't go out of bounds too much.
:
:If the fuse blows while the set is on, did you replace all the condensers? I know this sounds redundant of what I always say, but condensers are probably the worst trouble you'll find in any antique electronic equipment. They leak and throw off values, and they open up (only sometimes). They do lovely little spontaneous arcing that you have no clue about because it only happens for a moment, throws things off, ruins a part, or blows a fuse, and the arcing often cannot be recreated with your multi-meter, as it uses very low voltage. The only way to properly test condensers if you intend on reusing them is with a high voltage tester. You can find Solar capacitor testers on eBay, which are awesome little pieces of equipment with the 6E5 magic eye tubes. You can also build a simple capacitor tester that doesn't test capacitance, but tests for leakage using 100 volts or more, which will cause arcing if arcing does happen. Simply build either an AC/DC 110 volt power supply (use a solid state rectifier or a 117Z6 tube and some filter condensers, and put some 50 to 100K resistors in series with each supply lead to protect the supply againts shorts......connect supply in series with your multi-meter set to voltage appropriate to that being used, and connect condenser in question in series with the former two), or you can build an AC power supply (using the above techniques except with an AC transformer of 200 to 350 volts output and an appropriate 5Y3 or 80 rectifier, etc.).
:
:Other causes could be arcing at a tube socket or a faulty wire or wires that are too close, yoke to aquadag, high voltage to something, Lord knows what. With televisions, cleanliness is essential. The carbon and material that collects in mere dust can cause catastrophic disaster. The picture tube anode lead must be incredibly clean. If the black residue cannot be removed from the lead, put shrink wrap around the lead for its entire length. The HV rectifier socket and its surroundings must be incredibly clean as well. Make sure that all cages and covers do not touch any leads or come close to any leads.
:
:You could have a transformer that is arcing. You name it. If you see black greasy dirt film on the underside of the chassis, this needs to be cleaned away from contacts. This can cause all sorts of trouble. Use a Q-tip and alcohol or acetone. Be careful. Don't go nuts, but if you suspect that the grime is causing trouble, then you need to clean it up. Be critical of high voltage terminals and leads.
:
:Of course you said that you tested the tubes. Tap them and test each element against the others. Make sure they don't short out occasionally. I'm working on a radio for a friend right now, and the 6F6 tubes are incredibly fine. They have the nicest emission. Still, when I turn the radio upside-down to adjust the circuitry, one of them has a bit of debris that shorts out the screen grid and causes the screen grid resistor to overheat. Now, this only happens once in a great while for a moment, so unless you pay attention, you'd never know what was causing the smoke. Tap the tubes and turn the radio right-side-up, and all is well all the time, well, except for once there was an arc that jumped in one of the tubes when the volume was turned up really loud. Turn it upside-down, and you don't know what will happen.
:
:Don't let anything go unlooked. Sad to say, anything can cause the trouble. Sometimes it takes months of patients and sometimes leaving the set on the back burner, to find a qwerky little intermittent problem.
:
:Good luck!
:
:Thomas

Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.

Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.

High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.

Do you have a schematic for this television that I could see?

Thomas

Dave: Have you got around to monitoring that fuse circuitry with a milliameter (or even a 1 ohm resistor with a voltmeter across it) in line to watch the
current rise to see if it is gradual or in a fast rise as the sweep circuitry warms up ?
Dave: What it is that yuou have on your hands is an ~500 pf.....no make that mmf, then.....Doorknob filter
cap for the high voltage.....later days with glass tubed the aquadag coating of glass tubes sufficed for its replacement. It was always fun to get a loose doorknob and fully chg it and leave it around for the unsuspected.
73's de Edd

:Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.
:
:Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.
:
:High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.
:
:Do you have a schematic for this television that I could see?
:
:Thomas
:
:

Edd,
I put a 110 ohm resistor from pin 8 (cathode) on the Horizontal Output tube to the chassis, instead of a direct connection because Norm said the fuse wont blow with the resistor there. I measured the voltage and it was zero because the fuse blew.
It should not have happened. Why is this happening?
I'll bet it will fry a 1 ohm resistor if I put it where the fuse should go. The slow blow fuse is more than one ohm and it opens up with a nice loud click.

Do you have any other ideas?

Thanks,

Dave...
:Dave: Have you got around to monitoring that fuse circuitry with a milliameter (or even a 1 ohm resistor with a voltmeter across it) in line to watch the
:current rise to see if it is gradual or in a fast rise as the sweep circuitry warms up ?
:Dave: What it is that yuou have on your hands is an ~500 pf.....no make that mmf, then.....Doorknob filter
:cap for the high voltage.....later days with glass tubed the aquadag coating of glass tubes sufficed for its replacement. It was always fun to get a loose doorknob and fully chg it and leave it around for the unsuspected.
:73's de Edd
:
:
:
::Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.
::
::Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.
::
::High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.
::
::Do you have a schematic for this television that I could see?
::
::Thomas
::
::

----------------------------------------------------------------------------------------------------------------------------------------------------
OK, First of all, will the fuse blow if the damper tube is unplugged when powering up ?
Also how about going over to the terminal of the fuse that is NOT connected to pin 5 of your damper and with no fuse in circuit...(that won't be a problem!) take a resistance check of that terminal to ground and see what resistance it is. Sounds like it will be a matter of isolating feeds off the B+ and isolating them one by one to see who the culprit is puling excess current.
73's de Edd
-------------------------------------------------------------------------------------------------------------------------------------------------------

:Edd,
: I put a 110 ohm resistor from pin 8 (cathode) on the Horizontal Output tube to the chassis, instead of a direct connection because Norm said the fuse wont blow with the resistor there. I measured the voltage and it was zero because the fuse blew.
: It should not have happened. Why is this happening?
: I'll bet it will fry a 1 ohm resistor if I put it where the fuse should go. The slow blow fuse is more than one ohm and it opens up with a nice loud click.
:
:Do you have any other ideas?
:
:Thanks,
:
:Dave...
::Dave: Have you got around to monitoring that fuse circuitry with a milliameter (or even a 1 ohm resistor with a voltmeter across it) in line to watch the
::current rise to see if it is gradual or in a fast rise as the sweep circuitry warms up ?
::Dave: What it is that yuou have on your hands is an ~500 pf.....no make that mmf, then.....Doorknob filter
::cap for the high voltage.....later days with glass tubed the aquadag coating of glass tubes sufficed for its replacement. It was always fun to get a loose doorknob and fully chg it and leave it around for the unsuspected.
::73's de Edd
::
::
::
:::Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.
:::
:::Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.
:::
:::High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.
:::
:::Do you have a schematic for this television that I could see?
:::
:::Thomas
:::
:::

Thomas,
I have the SAMS Photofact for this set. Hmmmmmmmmm.... is what I say too. Which resistors do you want me to replace? I don't know what you mean by "those resistors". Do you mean the 100 ohm ones that have become 150 ohms? This is an aquadag coated tube. I have seen the capacitor you describe, but this set doesn't have one. It's from 1955.
This picture tube is brand new, as I said earlier. So is the yoke because those things were smashed in shipping.

Where should I look next?

Thanks,

Dave...
:Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.
:
:Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.
:
:High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.
:
:Do you have a schematic for this television that I could see?
:
:Thomas
:
:

You said that an 8.2K and a 47K resistor were open, but now that I think of it, you already replaced those.

Thomas

:Thomas,
: I have the SAMS Photofact for this set. Hmmmmmmmmm.... is what I say too. Which resistors do you want me to replace? I don't know what you mean by "those resistors". Do you mean the 100 ohm ones that have become 150 ohms? This is an aquadag coated tube. I have seen the capacitor you describe, but this set doesn't have one. It's from 1955.
: This picture tube is brand new, as I said earlier. So is the yoke because those things were smashed in shipping.
:
: Where should I look next?
:
:Thanks,
:
:Dave...
::Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.
::
::Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.
::
::High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.
::
::Do you have a schematic for this television that I could see?
::
::Thomas
::
::

Thomas,
Yes, I did and they're fine. The fuse blows when the horizontal output tube is out. I have no idea how that can be.

Dave...
:You said that an 8.2K and a 47K resistor were open, but now that I think of it, you already replaced those.
:
:Thomas
:
::Thomas,
:: I have the SAMS Photofact for this set. Hmmmmmmmmm.... is what I say too. Which resistors do you want me to replace? I don't know what you mean by "those resistors". Do you mean the 100 ohm ones that have become 150 ohms? This is an aquadag coated tube. I have seen the capacitor you describe, but this set doesn't have one. It's from 1955.
:: This picture tube is brand new, as I said earlier. So is the yoke because those things were smashed in shipping.
::
:: Where should I look next?
::
::Thanks,
::
::Dave...
:::Hmmmmmmmmmmmmmmm.............. we're all gonna have to think on this one. Interesting. What happens when you replace those resistors? Are they in the HV section? Usually the HV section uses the aquadag as a filter capacitor on the anode current, but my 630TS also has a small weird looking bakelite object with two screws coming out of it (one out of each end). This is a very small value secondary filter condenser. I've heard that these short out, and they're fairly hard to obtain. Your's, being a much newer television than my 630TS, probably doesn't have such a component. I havn't seen this component in any newer television.
:::
:::Have you tested each element in the picture tube with your multi-meter to see if there are any shorts there? When testing any suspected elements, consult a diagram to see what they connect to, and then check every other pin with the meter to see that they are not connected to something else.
:::
:::High voltage sections are annoying, because a lot of very small stuff can cause trouble that would not normally happen with low voltage equipment. Also, if you were able to operate the set before and now it is blowing fuses again, check the components you replaced. One of them could have failed, too, especially if you accidently put in the wrong voltage condenser in the higher voltage section. Make sure that the flyback hasn't opened up anywhere, or that it hasn't developed a short to the chassis somehow.
:::
:::Do you have a schematic for this television that I could see?
:::
:::Thomas
:::
:::

The fuse blows only when the horizontal output tube is out? Do you remove the tube to do other work on the set without creating high voltage? Well, one obvious thing I can think of, but you probably already have, too, is to make sure that the lead that goes to the top of the tube (plate lead) does not touch the chassis. I assume your HOT has a plate cap on top.

It can still be a shorted flyback (primary to secondary or to core) since B+ goes to the flyback before it goes to the 6BQ6 plate.

Try disconnecting the B+ feed to the flyback- but be sure you have the 6BQ6 out of socket or you'll burn up the screen grid.

And if you connect a large light bulb in series (or place of) the fuse, it will provide current limiting and also give you an indication of the current while you are trouble-shooting.

-Nat

:Thomas,
: Yes, I did and they're fine. The fuse blows when the horizontal output tube is out. I have no idea how that can be.
:

:Thomas,
: I have the SAMS Photofact for this set.

--------Could I see the Sam's Photofact?

T.

Thomas,
I discovered the problem and have eliminated the part from the neck of the picture tube. On the old picture tube a sheet of metal was wrapped around the neck under the yoke and a spring ring connected to the chassis was attached to it. Somehow this sheet was shorting out the horizontal winding (scratching against it). It wasn't zero ohms, because it was dirty, but it was enough to blow the fuse. I could tell that was it because when I moved the yoke around the resistance kept changing like crazy. There were positions of high resistance and positions where the resistance was low. That would account for the intermittents.
Now I have sound but a narrow picture. I have a coil I can use for width and I think I have it connected in the right place but I'm not so sure. With no width control the picture is narrow too.
The damper tube is good because it works in another tv. What would make the picture narrow? Vertical deflection is good.

How can I get a copy of the schematic to you? This forum doesn't allow pictures.

Thanks,

Dave...
::Thomas,
:: I have the SAMS Photofact for this set.
:
:--------Could I see the Sam's Photofact?
:
:T.

Thomas,
I removed the width coil from the circuit and voila, I have full horizontal deflection.
That sheet of metal was causing all kinds of problems.

Dave...
:Thomas,
: I discovered the problem and have eliminated the part from the neck of the picture tube. On the old picture tube a sheet of metal was wrapped around the neck under the yoke and a spring ring connected to the chassis was attached to it. Somehow this sheet was shorting out the horizontal winding (scratching against it). It wasn't zero ohms, because it was dirty, but it was enough to blow the fuse. I could tell that was it because when I moved the yoke around the resistance kept changing like crazy. There were positions of high resistance and positions where the resistance was low. That would account for the intermittents.
: Now I have sound but a narrow picture. I have a coil I can use for width and I think I have it connected in the right place but I'm not so sure. With no width control the picture is narrow too.
: The damper tube is good because it works in another tv. What would make the picture narrow? Vertical deflection is good.
:
: How can I get a copy of the schematic to you? This forum doesn't allow pictures.
:
:Thanks,
:
:Dave...
:::Thomas,
::: I have the SAMS Photofact for this set.
::
::--------Could I see the Sam's Photofact?
::
::T.
:

Doesn't it suck when things are as unusual as that? When you've searched every component, it's always something freakish like that, which you'd never think of.

Good luck with the set!

T.

GREAT GOBBEDY GOO and shades of deja vu...ergo...
Quote:
<>
that was on/in the other posting on another string that you had started on the same 17T40.
73's de Edd
Vertical info fwd'd via E-mail.
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:Doesn't it suck when things are as unusual as that? When you've searched every component, it's always something freakish like that, which you'd never think of.
:
:Good luck with the set!
:
:T.

:GREAT GOBBEDY GOO and shades of deja vu...ergo...
: Quote:
:[[[ Lastly , check the neck of the picture tube and see if there was an insulated brass sheet sleeve that is encircling the kine and pushed forward between the kine neck and inside the yoke area encircling the kine…..serving to adjust the hoz sweep width of the displayed raster. Age, heat and time makes hairline cracks in its external plastic sheathing resulting in hoz yoke windings arc over to it. It can be removed for testing .]]]
:that was on/in the other posting on another string that you had started on the same 17T40.
:73's de Edd
:Vertical info fwd'd via E-mail.
:----------------------------------------------------------------------------------------------------------------------------------------------
::Doesn't it suck when things are as unusual as that? When you've searched every component, it's always something freakish like that, which you'd never think of.
::
::Good luck with the set!
::
::T.

::GREAT GOBBEDY GOO and shades of deja vu...ergo...
:: Quote:
::[[[ Lastly , check the neck of the picture tube and see if there was an insulated brass sheet sleeve that is encircling the kine and pushed forward between the kine neck and inside the yoke area encircling the kine…..serving to adjust the hoz sweep width of the displayed raster. Age, heat and time makes hairline cracks in its external plastic sheathing resulting in hoz yoke windings arc over to it. It can be removed for testing .]]]
::that was on/in the other posting on another string that you had started on the same 17T40.
::73's de Edd
::Vertical info fwd'd via E-mail.
Addenda:
I just realized that I copied your chassis schematic page, so I have it here . Consulting it, you will see that there is no width coil nor linearity coil used in this chassis design. The width was controlled by the negative inductive/dampening effect of that brass shim sheet being inserted up into the yokes magnetic deflection path. So check to see if the 'BQ6's screen voltage is high enough (~135VDC), also the emission health/gain of the 6SN7 and 'BQ6 and the -36 V negative voltage on the first grid of the output...measured with a highZ meter or a digital unit. If it is low, shunt/tack in to C71..220 pf with about an extra 50pf ( making ~270 pf)and see if width/drive increases.
ZUJ'ing....Edd

::----------------------------------------------------------------------------------------------------------------------------------------------
:::Doesn't it suck when things are as unusual as that? When you've searched every component, it's always something freakish like that, which you'd never think of.
:::
:::Good luck with the set!
:::
:::T.