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  #16  
Old 07-27-2018, 04:20 PM
zeno zeno is offline
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Location: New Hampshire
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BTW for all.........
MOST horizontal outputs ( HOT's) from the late 70's on have a built in
damper diode & base resistor. The resistor goes from B-E & screws up
that reading. The damper diode will give a diode reading E-C one way
& wide open the other on the meters diode setting.

BTW #2
I lied ! I had ONE HOT open out of hundreds I found shorted. In a Zenith
custom series 25".

BTW #3
Quick check of HOT is ground meter & measure C to ground. If shorted
unsolder the HOT's C & retest. if no short its somethin else like FBT.
If the HOT is shorted the fun begins finding out why it did without
blowing parts.

73 Zeno
LFOD !
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  #17  
Old 07-27-2018, 09:11 PM
Sealtest Sealtest is offline
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Quote:
Originally Posted by zeno View Post
Yup all modern colors have a DGS coil.
Set is unlisted in Sams. Look on CRT socket for a chassis ##
like K20. If not there look on main board. We can still go father
without a manual.

73 Zeno
LFOD !
According to the socket the model is "K-50".

The board has no number, but it does say "file name: CT513V". Is this something to do with the SAMS?

Also I should have ordered the STR30125 shouldn't I?
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  #18  
Old 08-04-2018, 08:38 PM
Sealtest Sealtest is offline
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Got the parts in today and have a small issue. The new 2sd1555 reads the same as the old. I have not found any bad parts in that case, so I am not sure where to look next. I think maybe a cap went bad but so far all caps are in spec.
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  #19  
Old 08-05-2018, 09:27 PM
Sealtest Sealtest is offline
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Found a bad resistor and replaced it. I did the power up procedure and the set did not go over an amp... at first. The raster was an odd rainbow mixed with the way a screen looks when it has bad caps (caps in the power and hv section are good). The screen was slowly flashing and causing the amp meter to jump between .8 amps up to 1.1 amps with each pulse. The set also smelled like a very warm tv but it smelled stronger so I am not sure if something is dying or what. The pulsing is the main concern since it was a bit unsettling.
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  #20  
Old 08-06-2018, 10:00 PM
Sealtest Sealtest is offline
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Disregard. It is still drawing 1.5 amps.

Here is a picture of the screen though.

I have started recapping and testing every single part but nothing is bad so far so I guess I will have to check it all again. There is an IC chip of some sorts in the HV section. Maybe that could be the problem but it is unmarked.
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File Type: jpg IMG-5750.jpg (63.7 KB, 15 views)
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  #21  
Old 08-07-2018, 03:24 PM
zeno zeno is offline
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Run for about 30 sec then unpower & feel the 2SD1555.
To hot to touch most likely bad FBT or rectifier off it.
If cool or a little warm turn up variac & see if things improve.
The amps sometimes fall as the AC volts go up.
Keep in mind the HOT can short again if not careful. My advantage
doing this was knowing what I could get away with !

73 Zeno
LFOD !
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  #22  
Old 08-09-2018, 12:29 AM
Sealtest Sealtest is offline
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Quote:
Originally Posted by zeno View Post
Run for about 30 sec then unpower & feel the 2SD1555.
To hot to touch most likely bad FBT or rectifier off it.
If cool or a little warm turn up variac & see if things improve.
The amps sometimes fall as the AC volts go up.
Keep in mind the HOT can short again if not careful. My advantage
doing this was knowing what I could get away with !

73 Zeno
LFOD !
When I stop fighting with that trinitron project I'll try this.

I'm starting to wonder if something isn't getting enough power in the set. With the Samsung at 90vAC it looks like the trinitron screen at around 50ish volts. I'd suspect caps but they've all tested good so far. Dang TVs are a challenge compared to other electronics.
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  #23  
Old 08-09-2018, 08:53 PM
Sealtest Sealtest is offline
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Quote:
Originally Posted by zeno View Post
Run for about 30 sec then unpower & feel the 2SD1555.
To hot to touch most likely bad FBT or rectifier off it.
If cool or a little warm turn up variac & see if things improve.
The amps sometimes fall as the AC volts go up.
Keep in mind the HOT can short again if not careful. My advantage
doing this was knowing what I could get away with !

73 Zeno
LFOD !
The transistor was cool to the touch and raising the AC caused the amps to go up. Then the screen started pulsing and an odd smell filled my shop. Something is giving off heat somewhere on the board. A laser thermometer really would come in handy probably.

I'm going to look through some case histories and see if any sets in the book have had the same issue or something close.
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  #24  
Old 08-10-2018, 10:45 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Sealtest View Post
The transistor was cool to the touch and raising the AC caused the amps to go up. Then the screen started pulsing and an odd smell filled my shop. Something is giving off heat somewhere on the board. A laser thermometer really would come in handy probably.

I'm going to look through some case histories and see if any sets in the book have had the same issue or something close.
Feel the electrolytics and see if the main one is getting hot or warm. They can give off a funny smell as well.
It's a good learning tool, but unfortunately it's not worth the money and effort you're putting into it.
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  #25  
Old 08-10-2018, 10:14 PM
Sealtest Sealtest is offline
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Quote:
Originally Posted by dieseljeep View Post
Feel the electrolytics and see if the main one is getting hot or warm. They can give off a funny smell as well.
It's a good learning tool, but unfortunately it's not worth the money and effort you're putting into it.

Haven't felt the cap for heat yet, but I can smell something strong when the set is on. Kinda like a mix of burning rubber and warm electronics smell, but it fills the room kinda fast.

Yeah I have to agree. TVs are good to learn on but make no money. But if I was into it for the money I wouldn't be doing it. Personally I just really hate flat screen TVs and want these CRT sets to stick around in general circulation as long as possible.
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