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JTS1957
Joined: 21 Jan 2009
Posts: 1387
Location: Far, Far Away
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 Posted: Mon Aug 01, 2011 10:04 am Post subject: |
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| I would replace with a new capacitor. |
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chumba
Joined: 01 Jul 2009
Posts: 66
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| Posted: Sun Aug 21, 2011 4:54 pm Post subject: |
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Replaced C306=3300ufd and C322=2.2ufd and fuse F301, but same problem occurs - fuse blew again. All electrolytic caps in the 300 (vert) section have been replaced. DCV measurements on vertical IC301:
Pin1=0v
2=-0.25v
3=0.4v
4=-2.1 mV
5=-0.11v
6=-0.4v
7=-61 mV
No DC supply voltage seems to be getting to this IC301 which is expected since the fuse blew (connects to VCC pin 6).
The C310/R327 junction measures 34 vDC and R327 measures 5.4 ohms. Could this IC supply voltage be too high - it should be about 28v ?
Also immediately after unplugging the set, across the F301 fuse terminals measures a short (with fuse removed), which shouldn't be. I then discharged across the fuse terminals and the short disappeared. This seems very odd. |
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chumba
Joined: 01 Jul 2009
Posts: 66
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| Posted: Thu Aug 25, 2011 3:11 pm Post subject: |
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| Anything else that should be checked? How about the Diode connected to the vert IC? |
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chumba
Joined: 01 Jul 2009
Posts: 66
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| Posted: Sat Aug 27, 2011 6:28 pm Post subject: |
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| D301 & D302 check ok. Removed IC301 and fuse F301 does NOT blow after powering on TV. With IC301 removed from TV, no 2 pins of IC301 measured shorts across them, and from pin 1 to the 6 other pins measure 0.44 or higher on DMM Diode test mode. Also swapped out C320 again with IC301 removed and fuse does not blow. It looks like IC301 should be replaced then? |
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JTS1957
Joined: 21 Jan 2009
Posts: 1387
Location: Far, Far Away
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| Posted: Sat Aug 27, 2011 8:31 pm Post subject: |
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| JTS1957 wrote: | Excessive current will blow a fuse.
Remove Q301 making sure there are no solder bridges. Install a good F301 and see if it blows instantly when set is powered up. If NO - replace Q301. |
Hate to say "I told you so"... (You say "IC" - Toshiba says "Q") |
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chumba
Joined: 01 Jul 2009
Posts: 66
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| Posted: Tue Nov 15, 2011 6:27 pm Post subject: Toshiba CF30F40R No vertical ***FIXED!*** |
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I'm ecstatic to say that I replaced IC301 and viola, now have full vertical!!! YESS!! Finally got one in the Fixed category! Thanks much for all the help JTS and others, learned alot in the process and minimized the smell of burning parts  |
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JTS1957
Joined: 21 Jan 2009
Posts: 1387
Location: Far, Far Away
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| Posted: Tue Nov 15, 2011 6:55 pm Post subject: |
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Glad it's working.
P.S. I told you so. |
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