Panasonic CT-1310M keeps blowing horizontal output transistor

[vol.2]

it's in pretty rough shape by the looks of it. unfortunately, the commercial versions rarely have a sam's, but you might be able to find a consumer equivalent that has a fairly similar PCB in it.

any set i've worked on from that time period has always had a bunch of bad caps in it, and frequently bad transistors or even resistors in them. resistors that see a lot of heat can cook and die. anything anywhere around the deflection and power supply you should suspect and test

honestly wouldn't be worth it if you can't get the flyback, and you wanna test the strength of the tube as well

would be a real shame to spend a bunch of time and money fixing up a set just to find it has a dim tube, etc

[luRaichu]

Originally Posted by vol.2

it's in pretty rough shape by the looks of it. unfortunately, the commercial versions rarely have a sam's,

This model does have a Sams' but I'm not paying $22 for it. https://www.samswebsite.com/en/photo.../model/CT1310M
I should ask my library if they have Sams', I doubt they do though.

Originally Posted by vol.2

would be a real shame to spend a bunch of time and money fixing up a set just to find it has a dim tube, etc

From what I've seen while the HOT was alive the picture tube is still good.

Image is monochrome because I accidentally had the 75Ω switch flipped on and ColorPilot off; the colorburst must've been decimated.
Image is blurry probably because of the above + focus was set wrong.

Here it is also with the 75Ω resistance on the composite signal but with ColorPilot on.

Originally Posted by vol.2

but you might be able to find a consumer equivalent that has a fairly similar PCB in it.

There's likely a consumer set that uses the exact same PCB since mine has empty traces where tuning circuits would go.

[damen]

I have the Sams if you have any questions. Before you try another output transistor, resolder the driver transformer (T501) and any connections where a stake goes through the board and has a wire wrapped on it going to the output transistor. Also, resolder the flyback circuit board connections.

[luRaichu]

Originally Posted by damen

I have the Sams if you have any questions. Before you try another output transistor, resolder the driver transformer (T501) and any connections where a stake goes through the board and has a wire wrapped on it going to the output transistor. Also, resolder the flyback circuit board connections.

I'd be happy if you PM'd me the Sams' for this TV; these should all be on the Internet Archive anyways. Tomorrow I will check the resistors.

Would there be any danger in reflowing the solder on those components without discharging first? I don't have anything to perform a safe discharge at the moment. Maybe two old multimeter leads soldered together and wrapped in electrical tape will do, if they're rated high enough. I'd rather not get shocked.

[damen]

I doubt that there's any shock danger if the set hasn't been powered on for a couple of days. After this length of time, the CRT would be the only charged item, maybe, that would only be a problem if you were to remove the high voltage connector. If it makes you feel better, any piece of wire bridged across the large electrolytics would discharge them. Zeno has a very good idea. Using a light bulb in place of the fuse would limit the current to the circuit, if the circuit is "normal", the bulb stays dim, an overload will cause it to be bright and you can remove power before another transistor is destroyed. Since the set does play for a "few" minutes, turn it off and feel if the transistor is cool or warm. After a few minutes if everything is normal, it should still feel cool. No shock danger as long as its off. Sorry, I don't have anyway to PM anything. I used to post diagrams on Videokarma, but they changed something and all it says is my images are too large.

[luRaichu]

Originally Posted by damen

I doubt that there's any shock danger if the set hasn't been powered on for a couple of days. After this length of time, the CRT would be the only charged item, maybe, that would only be a problem if you were to remove the high voltage connector. If it makes you feel better, any piece of wire bridged across the large electrolytics would discharge them. Zeno has a very good idea. Using a light bulb in place of the fuse would limit the current to the circuit, if the circuit is "normal", the bulb stays dim, an overload will cause it to be bright and you can remove power before another transistor is destroyed. Since the set does play for a "few" minutes, turn it off and feel if the transistor is cool or warm. After a few minutes if everything is normal, it should still feel cool. No shock danger as long as its off. Sorry, I don't have anyway to PM anything. I used to post diagrams on Videokarma, but they changed something and all it says is my images are too large.

You can mail me: luraichu2630 at gmail dot com. I felt the HOT right before it died, it was cold. I covered it with one layer of electrical tape to make touching safe even when live. e-tape is rated for up to 600v and that's the maximum voltage of the original HOT according to datasheets.

You can use imgbb to host pictures but don't count on them to keep your pics for decades. Also they like to add weird things to the end of their generated bbcode so make sure to remove it.