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View topic - DAV-C700 error code C-81

DAV-C700 error code C-81

This forum addresses questions on installation, configuration and troubleshooting you might encounter with your Sony DVD player.

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by jehill » Wed Nov 03, 2004 9:45 am

I am happy to hear that you were able to install the modifications with so little difficulty.  Glad to be of assistance!
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by Gromble » Sat Feb 19, 2005 7:50 am

Hi All - what a great resource this site is.

I have a Sony DAVS-500 which was giving the C-81 error code.

I have followed the instructions for changing the transistor (recommended on is available from www.dalbani.co.uk  along with lots of other electronic service parts.  I have also placed a 1K ohm resistor in parallel as per ChrisB's great advice in reponse to John's excellent advice!!!

Now when i switch on all appears well - drawer opens then closes.laser fires up but always shows up with no disc message regardless of disk.  Also the new transistor is getting red hot - actually melted solder off once!

I have a spare transistor and was wondering if i should swap it and see if anything different happens.

Does anybody have any ideas?

Regards

Ian
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by jehill » Sun Feb 20, 2005 10:42 am

Gromble-
Exactly what changes did you make?  Did you make the changes outlined by ChrisB_UK?  If so, you need to be very carelful not to create solder bridges that will short out portions of the circuitry.  The new transistor definitely should not be getting red hot.  You need to verify that you have connected the emitter, base and collector to the correct points on the circuit board and that there are no solder bridges.
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by Gromble » Mon Feb 21, 2005 1:05 pm

Hi John

Thanks for reply.

I followed the instructions but the first time I tried to solder two wires to the surface mounted R011 resistor and then connected a 1/4 watt 1k ohm to the flyleads.  It was OK until I turned it over then realised it had come off.

To cut a long story short I now have it as per the direct connections (I fitted a conventional 1k between the base of Q002 (pin immediately below R011) and the pin of Q001 immediately above R011 (both when looking at the board as shown in the diagram for step 2).

I have to look at how I did it and have three weaknesses.  I only had a 40 watt large bit soldering iron and did not have a magnifying glass.  As the resistor in particular now has solder flux on it and shines - it is very difficult to see if there are any shorts.

I am going to have another look at it and retrace all my steps.  I have already swapped the transistor with a new one and switched off immediately I felt it getting how - which wasn't long!

Your advice "The new transistor definitely should not be getting red hot", has stopped me pursuing laser problems etc and persuaded me to re-look at my work.

Thanks again - I'll update when it happens.

Ian

PS It appears to be a very common problem with the Sony DAVS series.
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by jehill » Tue Feb 22, 2005 1:18 pm

Yes it is.  The original transistor was under powered (not enough current handling capability for the application).
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by Gromble » Tue Mar 01, 2005 2:45 pm

To all my fellow sufferers of the dreaded C-81 error code - I am pleased to say that I have solved mine.

In the end I removed the small (R011) resisor from the board and soldered a new 1/4 watt 470 ohm and powered up and all was well.

I'm not sure if I damaged the resisitor or if it was part of the problem, anyway I couldn't measure it in situ.

My advice is to have a good localised light source and a magnifying glass.

The new transistor is a little tough one - no apparent damage despite getting red hot! 

Thanks to John for his responses.

I am now looking for a microwave site as my parent's has just gone off.

Hope everyone solves their C-81 prob's.
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by jehill » Tue Mar 01, 2005 2:49 pm

I am happy to hear that you successfully completed your repairs!  Good work!
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by c-81 » Tue Mar 08, 2005 4:41 pm

Great website and my thanks to all who have posted on this problem! I can’t believe Sony’s MTBF test didn’t pick up on this problem long before sending these products to market. A few weeks ago my DAV-C900 displays this weird c-81 error and my DVDs won’t eject???

Thank you John! The repair info that you generously provided worked like a charm. Out popped the discs and the unit is fixed! I crossed the transistor over to a NTE 153, soldered the leads on both ends, soldered in the 1k resistor in parallel per ChrisB_UK’s excellent suggestion and put a small amount of “creative” insulation on the transistor. Viola!

To clarify the location of the bad component a little further... it’s found on the underside of the DVD board, which is under the power board, on the corner closest to the center of the chassis. You may need to disconnect several of the flex tail connections to fully access this area of the board. If you choose to jumper the R011 resistor use caution to keep the 1k resistor from shorting to other areas of the board and chassis.  Also be careful when soldering the wires to the surface mount pads on the board; use very thin, very flexible wire. Not surprisingly the soldered wire can provide a lot of leverage and it can be quite easy to tear the copper pads off the board; then you’ll have a whole new problem.  This is not a repair for a novice but it’s actually not all that difficult for those with some basic skills and some common sense.

Cheers! Marcus

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by jehill » Wed Mar 09, 2005 11:04 am

c-81-
Welcome to Agoraquest!  I am happy to hear that there is yet another happy camper!  Your experience with the fix may help another.
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by skiergary » Thu Mar 24, 2005 11:12 pm

Thank you in advance. I did the mod and worked fine but then the power supply smoked. Found witch part it was. its a L904 on the back side of power supply board. Can anyone tell me what I can replace this with?
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