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DSF68NX IDC2 Stuck in stand by
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PostPosted: Tue Jun 28, 2005 6:51 pm    Post subject: Reply with quote

Hi absorbentgnome

I found the standby problem, it was CP48. I noticed a lot of AC after the diode, so knew that the cap must be causing the problem. Unfortunately although it now starts up the screen is a very dark blue with very thin white lines across it. Although I have no picture, when I press the buttons on the remote that change the format from 4:3 to 16:9, the blue screen changes size. So I know that it is functioning all except the picture. When I put it onto one of the AV channels it sometimes makes a screeching noise and I get some colour flecks on the screen. Do you have any idea's for this problem? Is it likely that I have casued it by trying to fix the other problem or was it part of the original?

Whether or not you have any other suggestions on my new problem, can I just say a big thanks for your help. It is truley wonderful when someone you don't know invests their own time trying to help someone else out. You have restored my faith in the human race.

Matt
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absorbentgnome



Joined: 30 May 2005
Posts: 51
Location: Cardiff, UK

PostPosted: Tue Jun 28, 2005 8:14 pm    Post subject: Reply with quote

Excellent, I indeed did mean C48 not C47 in my post! Very Happy
Hmm, next problem then.
Look in the circuit diagram page titled 'Video Amplifier'.
Check the voltage on the 200V line (UL1) and the 12V line (U4). Might as well check the heater voltage too (will be ok if you are getting a nice bright picture).

Check RT06 and RT07 with your multimeter.
Check the fusibles RT21, RT61, RT41.

Then post back here.
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absorbentgnome



Joined: 30 May 2005
Posts: 51
Location: Cardiff, UK

PostPosted: Tue Jun 28, 2005 8:19 pm    Post subject: Reply with quote

I also thought I'd mention to check for ripple on the 12V supply as well, 'cos you might have a duff cap on there too. This may have caused IT01, the TEA5101A RBG driver chip to go bad.
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absorbentgnome



Joined: 30 May 2005
Posts: 51
Location: Cardiff, UK

PostPosted: Tue Jun 28, 2005 8:24 pm    Post subject: Reply with quote

Also, more obviously, if you have at least one bad PSU cap, then others could be on the way out. If you have a selection of caps to hand, then replace the secondary smoothing caps.
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PostPosted: Wed Jun 29, 2005 6:28 pm    Post subject: Reply with quote

Hi absorbentgnome


I have found that U1:40V is only at 24V. I have checked CP53, DP53 and CP51 and they are all OK. I cannot find anything that is bringing the voltage down. Any ideas? I checked the UL1:200V and U4:12V on the amplifier card and they are both OK. I am starting to think I will never fix this set and the wife is nagging me to buy a new one. I think I will give it a few more days then open the wallet and buy a new one.



Matt
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PostPosted: Thu Jun 30, 2005 7:48 pm    Post subject: Reply with quote

Replace DP53 and CP51 with NEW components. They will check ok on your multimeter but will be probably be pieces of crap.

Once you have replaced them check the voltage.

If still low, remove TP90 and RP90 and check again. If it comes back up to ~40V, replace TP90.

Good luck!
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absorbentgnome



Joined: 30 May 2005
Posts: 51
Location: Cardiff, UK

PostPosted: Thu Jun 30, 2005 7:52 pm    Post subject: Reply with quote

Check RP93 as well.
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