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#46
06-30-2023, 12:55 PM
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The one with arrowlike symbol ---|>|--- is the diode; the another 448 with ---||--- symbol nearby is a capacitor.
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So many projects, so little time... Last edited by Alex KL-1; 06-30-2023 at 01:02 PM. 
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#47
06-30-2023, 02:05 PM
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Ok, on component side, I found SC448. All I see are wires all around it. Is it pointing to the big brown thing below?
Last edited by pac.attack76; 04-19-2024 at 09:18 AM.
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#48
06-30-2023, 02:19 PM
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If the holes for the damper diode are currently not populated with any part, then they may have moved to an internal damper on the horiz output in a later production, but that would seem unlikely. Unsolder the component in the 448 diode (arrow) slot and measure that (and provide a pic) John
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#49
06-30-2023, 03:46 PM
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Ok I think I found it. It was under the brown thing lol. Do I in hook one leg or both?
Last edited by pac.attack76; 04-19-2024 at 09:18 AM.
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#50
06-30-2023, 05:55 PM
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To check for short ( damper) just one leg has to be lifted.
DO NOT power up set with damper out. Hoz outs & dampers are dead shorted or OK. In all my years only saw one hoz out opened with the exception of Sony SG-### devices. There is an easy process on most early SS sets. You need a manual and so would we to walk it through at this level. GL Zeno
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#51
07-01-2023, 08:06 AM
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Quote:
John
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#52
07-01-2023, 01:59 PM
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Ok I pulled one leg loose and put a lead on each end and got what you see on meter at that setting.
Last edited by pac.attack76; 04-19-2024 at 09:18 AM.
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#53
07-03-2023, 08:32 AM
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Install the diode back into the circuit, remount the horiz output, and retest the metal case of the transistor to ground to make sure the short is still there. Sometimes it's best to backtrack and start over. If the short is there between chassis ground and the metal case of the output, the two most likely culprits at this point are the retrace capacitor or a puncture in the mica insulator between the horiz output and the chassis (we tested the output before so we'll assume for the moment it's OK). If the short is now gone, remove and inspect the mica insulator under the horiz output transistor - these were very thin and prone to cracking or puncturing. Sometimes just resetting them with new heat sink compound clears a short, but because there's a 1500 volt pulse on it, it will arc through if you attempt to run it. If the mica insulator is damaged, replace it and you should be good to go. But if you install the output and get a low ohm short to chassis ground again, remove the two mounting screws of the horiz output and retest. If the short is still there, either the output or the mica insulator is bad. If the short disappears when the screws are removed, the output and mica are good. *Anything* that is connected to the B+ line and goes to ground is a suspect, including the main B+ filter, but since the tripler had what appears to be a puncture, we start closest to the HV and work back. Report back what you find with your meter. John Last edited by JohnCT; 07-03-2023 at 08:35 AM.
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#54
07-03-2023, 03:40 PM
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No holes or cracks in insulator. I cleaned and put new paste on. Meter showed 11 with it in and like 9 0r 10 with it out. Is there supposed to be paste on both sides of insulator?
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#55
07-05-2023, 10:27 AM
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If the metal case transistor collector is reading about 10 ohms from the metal to the chassis frame, then remove the two 1/4 hex screws and read again from the metal case of the transistor to chassis frame. Is it still 10 ohms about with the screws out? If so, the transistor is bad. If the short goes away with the screws removed, the short is on the chassis. A lot of those never came with any heatsink compound, some came with compound and some came with dielectric grease. A small amount on both sides of the mica is fine. John Last edited by JohnCT; 07-05-2023 at 10:32 AM.
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#56
07-05-2023, 01:42 PM
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When I took it out, it was reading about 10
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#58
07-05-2023, 05:22 PM
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Quote:
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#59
07-06-2023, 09:06 AM
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Back in the day, I used to order 2SC1172Bs (toshiba) a hundred at a shot. Back when SKs and ECGs cost $15 or more each, I would pay like $1.99 for the 1172s in quantity. Most TVs were happy with them, but there were some exceptions (some Sanyos for instance). See if there are any local legacy TV shops in your area that might have some kicking around (I don't). John
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#60
07-06-2023, 09:10 AM
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We don't have any here. Last one closed several years ago.
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Linear Mode
