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FIXED - CRT Top of the screen folding over?
LTC:
--- Quote from: princess prin prin on June 20, 2025, 09:09:27 am ---The vertical IC is the 7-pin IC401 (screwed to the heat sink near the rear of the tuner), probably an LA78040 or TDA8170 (same package, same pinout). The cap in question is across pin 3 (-) and pin 6 (+). I can't follow the traces in your pic so I can't tell which one it is but you should be able to identify it with this info (capacitance will most likely be 100uF).
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Thank you again. I found the IC. I will trace the pins to the cap.
Zebidee:
There seems to be some thermal stress going on (blackened/carbonisied area, see pic attached). Might be "normal", but might indicate something about to fail. Worth lookin', to see what's cookin'.
Maybe it is something to do with those three transistors?
What is that blue thing right in the middle of the circle? A tantalum capacitor!!?? They are known to fail dramatically (explode).
Not concerned about that nearby big resistor with a little carbonisation near the legs (just outside the yellow circle), as they are expected to radiate a lot of heat.
LTC:
--- Quote from: Zebidee on June 20, 2025, 04:23:22 pm ---There seems to be some thermal stress going on (blackened/carbonisied area, see pic attached). Might be "normal", but might indicate something about to fail. Worth lookin', to see what's cookin'.
Maybe it is something to do with those three transistors?
What is that blue thing right in the middle of the circle? A tantalum capacitor!!?? They are known to fail dramatically (explode).
Not concerned about that nearby big resistor with a little carbonisation near the legs (just outside the yellow circle), as they are expected to radiate a lot of heat.
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I see what you mean. I'll see if I can read any markings on that component.
LTC:
--- Quote from: princess prin prin on June 20, 2025, 09:09:27 am ---The vertical IC is the 7-pin IC401 (screwed to the heat sink near the rear of the tuner), probably an LA78040 or TDA8170 (same package, same pinout). The cap in question is across pin 3 (-) and pin 6 (+). I can't follow the traces in your pic so I can't tell which one it is but you should be able to identify it with this info (capacitance will most likely be 100uF).
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Thank you so very much. Cap replaced and CRT is fixed and looking great.
LTC:
--- Quote from: Zebidee on June 20, 2025, 04:23:22 pm ---There seems to be some thermal stress going on (blackened/carbonisied area, see pic attached). Might be "normal", but might indicate something about to fail. Worth lookin', to see what's cookin'.
Maybe it is something to do with those three transistors?
What is that blue thing right in the middle of the circle? A tantalum capacitor!!?? They are known to fail dramatically (explode).
Not concerned about that nearby big resistor with a little carbonisation near the legs (just outside the yellow circle), as they are expected to radiate a lot of heat.
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I took a closer look. The three transistors are labeled:
K-622
C3202
Y
Do you think I should replace those? The blue component with the red dot is unmarked and labeled L001 on the board.