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Thread: Does anyone know old TV's?

  1. #1
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    Default Does anyone know old TV's?

    I just bought a 1959 or so Philco Predicta Princess, one I've been looking for forever, and it seems to work but the picture is squiahed vertically and the seller said the picture tends to get more squished as it runs. I'll post pictures tomorrow but I was curious if anyone knew what caused this issue. I'm thinking capacitors but could it be something else like a bad vacuum tube?

  2. #2

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    Could be a tube but more likely a resistor, I would expect.

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  3. #3

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    Changing as it warms up sounds like old capacitors. Replace any wax or paper capacitors on sight. Fortunately these old sets don't have too many parts compared to today's ones, so you may as well replace all the capacitors and resistors in that area. TV Valves aren't that reliable either, so may as well replace the vertical output valve too.

  4. #4
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    Find a Sams Photofact for the set and get your meter or 'scope out. A "shotgun" replacement would probably be expensive and likely counter-productive.

  5. #5
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    like Robbbert said, the most common cause of issues are the capacitors. The paper inside them starts to go acidic over time and causes the capacitor to leak electrically, which makes the capacitor start passing DC. This can red plate tubes and destroy them. There are also "domino" capacitors which are mica style capacitors and tend to be pretty stable over time, and shouldn't be changed unless absolutely necessary.

    The allen bradley style resistors (brown body resistors) can also go bad from the heat, so it's a good idea to check all of them to be sure they're in tolerance (usually 20% tolerance unless otherwise specified.)

    I wouldn't power on the TV again until it is serviced, you can be doing damage to the set just by powering it on.

  6. #6
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    Quote Originally Posted by Chuck(G) View Post
    Find a Sams Photofact for the set and get your meter or 'scope out. A "shotgun" replacement would probably be expensive and likely counter-productive.
    As someone who replaced a '52 Westinghouse I found with TV's this old there was no option but replace everything but the ceramic and mica capacitors, then verify all the resistors to the schematic and repalce any that are out of spec.
    I think the biggest PITA about the electronics in a Predicta is the early printed circuit boards which crack around the tube sockets.
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  7. #7
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    You did notice that I linked to the Predicta Sams Photofact. Those things have been around for a very long time.

  8. #8
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    I've always been iffy about scoping out unrecapped TV's and radios. I've had both kill tubes from plate arc and smoke resistors because capacitors had internally shorted due to age and let voltages get to place it didn't need to be.
    = Excellent space heater

  9. #9
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    Yes, but in this case, the set is semi-functional, just lacks a bit in the vertical deflection. No melted anything.

  10. #10
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    The trouble with the Predictas is they were Philcos. Not the best crafted televisions of the era. You may find you have to duplicate component packs. Entire sub-circuits encased in epoxy. Age, proprietary components, and poor build quality will make for quite a project.

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