Vertical Collapse - Need Advice

[jeffez]

Hi Folks
I picked this KV-2585AS up from a charity shop in my area. I paid a fair bit for it (70 AUD) as it was tested and tagged and sold as fully working.
Turns out they didn't fully test it as I took it home and fired it up and was met with what I believe is Vertical Collapse.
The inside of the tv shows nothing obvious. No bulging caps etc so it's likely it will take some time to try and troubleshoot. I can't find any good info on fixing this issue so I'm not sure what I am really in for. This set is not RGB mod able which is another strike against it.

I do have a receipt so I can return it but these sets are rare in my area so unless it's allot of work I would prefer to just fix it.

Is fixing this issue normally fairly straight forward or can it be a bit of work?

What would you guys do? Just take it back or try and fix it? I could maybe try and get a partial refund but that still means taking it back and potentially damaging it more as I will have to prove it's faulty. Am I right in that leaving it running like that for any length of time could do significant burn in?

[matt]

You are correct that leaving it running will burn the tube very quickly. If you must turn it on, reduce the screen pot on the flyback to dim the picture.

Vertical collapse is among the most straightforward repairs to do, so it's definitely worth taking a shot at it. It's most often caused by a failed vertical deflection IC, and is usually accompanied by one or more failed capacitors. Replacing the IC and its associated caps will usually fix the problem.

It can also be caused by bad solder joints or a broken trace in the vertical circuit, most often at the yoke connector. Check this first, since it's the easiest thing to repair and should be easy to spot.

And if it turns out you can't fix it and it's still in the window for returns, take it back! The thrift store isn't going to open it up and check if you've messed with it or not.

[jeffez]

You are correct that leaving it running will burn the tube very quickly. If you must turn it on, reduce the screen pot on the flyback to dim the picture.

Vertical collapse is among the most straightforward repairs to do, so it's definitely worth taking a shot at it. It's most often caused by a failed vertical deflection IC, and is usually accompanied by one or more failed capacitors. Replacing the IC and its associated caps will usually fix the problem.

It can also be caused by bad solder joints or a broken trace in the vertical circuit, most often at the yoke connector. Check this first, since it's the easiest thing to repair and should be easy to spot.

And if it turns out you can't fix it and it's still in the window for returns, take it back! The thrift store isn't going to open it up and check if you've messed with it or not.

Ok cool thanks. I can rule out anything bad at the yoke connector so maybe it is the IC then. What do I need to be looking for on the datasheet so I can maybe find a replacement? I only have 3 more days to return it as they only give a week for returns.

It's a shame this can't be rgb modded as now I'm not sure if it's really worth my time vs getting my money back. I know they will just fry the tube testing it as understandably they won't know any better.

[jeffez]

Also the service manual says the adjustment on the flyback is for focus or is that what you mean?

EDIT: Sorry never mind found it on the neck board

[jeffez]

Ok well this is weird but after adjusting the screen pot and turning on the TV it magically just started working. I ran it for about 10 minutes and it was fine. But I did notice though after turning it off and on again for a second there was Vertical collapse. I tried a few power cycles and it was fine every other time. I will try again later when the set is cold. Perhaps this is heat related?

[SuperSpongo]

My guess is: cold solder joint. The TV techs in Germany appearantly used to have a proverb: Before switching on a Sony, first switch on the soldering iron.

[deezdrama]

My guess is: cold solder joint. The TV techs in Germany appearantly used to have a proverb: Before switching on a Sony, first switch on the soldering iron.

Thats hilarious, havnt heard that one but it does ring true in my experience... Out of my 20 or so pro monitors all of my sonys have needed work.

OP

If owning/maintaining a crt is in your future I would invest in a decent capacitor esr meter that can handle in circuit tests with some factor of reliability like the peak atlas or GME meters.
Check caps in vertical deflection for high esr (not good) and replace with quality 105c temp rated caps like nichicons or panasonics. While your in there check for short on vertical IC and get the package number off of it and see if you can find any new old stock on ebay but since its intermittent its likely a cracked solder joint or failing cap.

Or return it lol.

[jeffez]

Thanks for the help. I might look up getting an esr meter at some stage as being able to test caps in circuit would be extremely handy. Hopefully it's just soldier but I have a feeling this TV is not going to let me off that easy
Incidentally I did take it back as it still bothered me a little that I paid for it as working. I got a refund but since they were just going to throw it away I convinced them to just let me take it.

[deezdrama]

Thanks for the help. I might look up getting an esr meter at some stage as being able to test caps in circuit would be extremely handy. Hopefully it's just soldier but I have a feeling this TV is not going to let me off that easy
Incidentally I did take it back as it still bothered me a little that I paid for it as working. I got a refund but since they were just going to throw it away I convinced them to just let me take it.

Cool, sounds like you got a free project.
Better than a project you paid for lol.
Im dealing with a head scratcher myself.
Id say an esr meter is almost necessary when working on crts anymore, get you a good magnifying lense or visor as well to check for cracked joints. Good luck!

[jeffez]

Thanks for the help. I might look up getting an esr meter at some stage as being able to test caps in circuit would be extremely handy. Hopefully it's just soldier but I have a feeling this TV is not going to let me off that easy
Incidentally I did take it back as it still bothered me a little that I paid for it as working. I got a refund but since they were just going to throw it away I convinced them to just let me take it.

Cool, sounds like you got a free project.
Better than a project you paid for lol.
Im dealing with a head scratcher myself.
Id say an esr meter is almost necessary when working on crts anymore, get you a good magnifying lense or visor as well to check for cracked joints. Good luck!

Thanks! Will see how I go.

[deezdrama]

Thanks for the help. I might look up getting an esr meter at some stage as being able to test caps in circuit would be extremely handy. Hopefully it's just soldier but I have a feeling this TV is not going to let me off that easy
Incidentally I did take it back as it still bothered me a little that I paid for it as working. I got a refund but since they were just going to throw it away I convinced them to just let me take it.

Cool, sounds like you got a free project.
Better than a project you paid for lol.
Im dealing with a head scratcher myself.
Id say an esr meter is almost necessary when working on crts anymore, get you a good magnifying lense or visor as well to check for cracked joints. Good luck!

Thanks! Will see how I go.

Check all your resistors too near the flyback and inbetween the flyback and vert out, i just recently fixed a 14m2u with same issue and a resistor near the flyback was the culprit... It fed voltage to the vert outs and was fuseable and when I ohmed it it was wide open. Look for open resistors in other words lol

[jeffez]

Check all your resistors too near the flyback and inbetween the flyback and vert out, i just recently fixed a 14m2u with same issue and a resistor near the flyback was the culprit... It fed voltage to the vert outs and was fuseable and when I ohmed it it was wide open. Look for open resistors in other words lol

Interesting. So it turns out it was cold solder joints on two large resistors on the main board. They don't appear to be coming from the flyback but I made sure they were not open and within spec. At first I didn't see them and went ahead and replaced the 9 caps I could find connected to the vertical IC. All the caps I removed were in spec so probably didn't need to be replaced.

The take away for me with this is to look closer for cold solder joints as they are easy to miss and find a way to test caps in circuit.
Not a bad result in the end anyway! Might svideo mod it.

[deezdrama]

Check all your resistors too near the flyback and inbetween the flyback and vert out, i just recently fixed a 14m2u with same issue and a resistor near the flyback was the culprit... It fed voltage to the vert outs and was fuseable and when I ohmed it it was wide open. Look for open resistors in other words lol

Interesting. So it turns out it was cold solder joints on two large resistors on the main board. They don't appear to be coming from the flyback but I made sure they were not open and within spec. At first I didn't see them and went ahead and replaced the 9 caps I could find connected to the vertical IC. All the caps I removed were in spec so probably didn't need to be replaced.

The take away for me with this is to look closer for cold solder joints as they are easy to miss and find a way to test caps in circuit.
Not a bad result in the end anyway! Might svideo mod it.

Awesome... getting a tube working correctly always feels like a win, good job!

[SuperSpongo]

Congrats!
Cold solder joints are such a pain.