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train123_not logged on |
Posted: Mon Oct 25, 2010 4:34 pm Post subject: |
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Impedance has nothing to do with the magnets. Using 4 ohm speakers instead of the 8 ohm speakers causes double the current draw on the amp IC (which is why it overheated and blew). You'll want to stick with 8 ohm replacements when you get it all back together. |
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macusr191 |
Posted: Mon Oct 25, 2010 12:11 am Post subject: Yep |
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10W 2-channel audio output IC.
The blood was bright lime green with purple swirls!
Found quite a few different brand replacements anywhere from $3-$50. |
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jts1957 |
Posted: Sun Oct 24, 2010 11:53 pm Post subject: |
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What color was the blood?
LA4282= Audio output IC. |
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macusr191 |
Posted: Sun Oct 24, 2010 10:57 pm Post subject: just FYI |
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If the first poster is still having trouble.. My issue turns out to be the chip located @ D601. Burned and bleeding from the top. It is the sound controller as far as I know and is what causes F889 to blow almost instantly.
The original part # is LA4282
I will let you guys know if a replacement is possible. |
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macusr191 |
Posted: Sat Oct 23, 2010 2:22 am Post subject: sorry |
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Impedance... sorry. Brain is fried from messing with it. Anyhow do you think the turkey is fried? |
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jts1957 |
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macusr191 |
Posted: Sat Oct 23, 2010 1:08 am Post subject: D607 and D608 |
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Just throwing this out there for anyone wanting some light shed on this F889 debacle. Only I cause this myself.
Toshiba TP55H60 RPTV
I caused this exact problem by replacing the speakers with 4-ohm rather than 8-ohm jobbies. Went against my instincts and didn't put an ohmmeter to the replacements.. knowing all too well they might have been mislabeled. I am not sure if it was the low resistance of the new speakers causing this mess, or the magnets on them causing some other electrical distress.. Tubes are close.
Anyhow.. Just for reference this is what happened, exactly in this order.
I removed the old rotted speakers and chucked them. I started with one speaker connected and powered up. Perfecto. Note it was not mounted, just resting below the hole on the floor. Power off, I connect the 2nd and proceeded to mount them in the speaker holes.
Ok so both mounted, wired right, checked twice, I was done. Power on: popping like a guitar amp softly coming on or going off. Happy blinky red safe mode light. She is dead. It instantly ruined both zener diodes @ D607 & D608, shorting, and blowing fuse F889. Thank god i found this post i was going nuts finding the burned parts!
Realistically does anyone know if 4 vs. 8 could cause such immediate damage, or is it more likely the magnets? I have not repaired it yet so I cannot tell you if that was all the damage it took. Open for opinions before I waste an entire weekend desoldering things just to get to the bad juju. Is it worth the trouble?
Also.. would it be possible to just snip the two diodes, replace the fuse and have this thing work w/o sound? Or will the brain just sense that as a problem too and continue to blink at me? |
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minnie |
Posted: Mon Mar 08, 2010 11:27 pm Post subject: |
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Only alcohol! |
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Wildwilly01 |
Posted: Mon Mar 08, 2010 10:27 am Post subject: Thank you |
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Thank you for the quick responce. I will try replacing the diodes and let you know how I make out. do you accept donations?
Thanks again!
wildwilly01 |
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minnie |
Posted: Mon Mar 08, 2010 4:03 am Post subject: |
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Suspect D607 & D608 are shorted in audio circuit. Both are 22 volt zener diodes. |
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