Question about Sony CDX-M800 CD Player

1 Answer

Sony cdx m800 no display

Thanks for the reply re the Sony cdx m800 with no displays. As I say the ribbon cable has been fitted correctly & has not cured the problem, like you suggest I think it has a problem on the front panel as everything else works fine. Yes I am an electronics engineer & have all the necessary tools & power supply. So if you can give me any help or suggestions that would be great. I don't think it is the lcd as both displays are out, I assume it is a missing supply problem.

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 624 Answers

I think you are going to need the service manual to properly troubleshoot this. You can try to follow these instructions without one, but having one makes it so much easier. You will need to have the radio on a work bench with the CD mech out and the harness out of the car as well so you can turn on the radio and check some voltages. Since you are an electronics engineer, I should not need to point out any safety precautions, after all, I am just a technician.

For starters, check the voltages at pins 7,8,15,16,17 on connector CNP909 the 24 pin connector for the display on the main board. Pin 1 should be the one closest to the corner of the board that connector is near. Pins 7 and 8 should have 10 volts each, pin 15 should have 5 volts and 16 and 17 should both have a much higher voltage. I suspect you may be missing the 10 volts from pins 7 and 8. If so, check the voltage at the emitter of Q914 on the main board. It is a digital transistor (surface mounted) and when the power is on it should have 10 volts there and 10 volts on the collector and zero volts on the base. If any of those voltages are not there, check Q915. It should have 10 volts on the collector, 5 volts on the emitter and 5.6 volts on the base. It is not a digital transistor but is surface mounted and much bigger than Q914. If you are missing the 5.6 volts on the base, check the zener diode D905. It should have 5.6 volts on the cathode and ground on the anode. The cathode goes directly to the base of Q915. Use your multimeter on the diode check mode and see if it looks normal. Could be that zener diode is shorted. There is also 2 capacitors in parallel with that zener, C928 and C930, check those as well. If one of them shorts out it will look like the zener is shorted.

You can also check CNP805 for the 10 volts, it is supposed to be there as well. I don't know what pin number but I think that connector is on the top of the board. The 10 volts should be either pin 5 or pin 7, depending on which side you start at. CNP805 is the connector for the sub-board with the reset switch on it. After you know what these voltages are on CNP909 we should be able to narrow down the problem.

I hope this helps, I really do not have a lot of time right now. I have a power supply to fix and a big stack of car amplifiers to repair. Let me know if you need more help, I just may not be able to answer as quick as you may like, but I will answer when I have time.

Dave

Posted on Jan 27, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Sony CDX-M800 inside face (buttons and display) do not work


you more than likely have a bad flexible cable(s).

Dec 23, 2009 | Sony CDX-M800 CD Player

1 Answer

Sony cdx-M8800 car stereo buttons wont work


There is a ribbon cable that runs all the flip panels electrics, these are prone to breakage.
I have seen some of the cables on e-bay for a few quid, and also if you google "sony x-pod ribbon cable" you will get a big choice of places to order, and get instructions on fitting.

Aug 25, 2009 | Car Audio Receivers

1 Answer

Black out


this is a coincedence. The CDX-M800 had a HUGE problem with the ribbon cable on the face going bad, causing this exact problem.
$14.00 and some time will put it back into perfect condition.
http://cgi.ebay.com/ebaymotors/Fix-your-Sony-CDX-M800-flexible-ribbon-cable-CDX-M800_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQcategoryZ43947QQihZ020QQitemZ300287945333QQrdZ1QQsspagenameZWD1V#ht_2258wt_1213

Jan 21, 2009 | Sony CDX-M800 CD Player

1 Answer

Can you help me?


That ribbon wire is called as "data cable or IDE cable" You can find it at any computer store..Should cost you around 3$

Dec 01, 2007 | Sony CDX-M800 CD Player

4 Answers

Please help


you can buy these from ebay just type in sony cdx m800 ribbon theres loads on there pretty cheap aswell hope this helps

Dec 01, 2007 | Sony CDX-M800 CD Player

1 Answer

No display on Sony CDX-M800


JUST PRESS THE RESET BUTTON
IF THIS DOSNT WORK CHECK THAT THE PLUG WIRES ARE SECURE I HAD THIS PROBLEM LAST YEAR AND IT TURNED OUT THAT ID UNPLUGGED THE STEREO BUT AS I RECONNECTED IT THE PIN HAD PUSHED THE CONNECTOR AWAY SO SOMETIMES IT WORKED OTHER TIMES IT DIDNT WHEN I HIT A BUMP IT WOULD MAKE THE CONNECTION BREAK

Nov 08, 2007 | Sony CDX-M800 CD Player

2 Answers

Sony CDX-M630


not open the face? or not get on the stereo? if not open the face maybe is too fit on the space for the stereo, check down if have space, if dont get on, check if are well conected

Nov 02, 2007 | Sony CDX-M630 CD Player

2 Answers

No display on sony cdx-m8800


if the remote makes it work and it plays ....if all functions work other than display check for bad solder joints on the display pay  attention to the ones on the corners if the unit is or was a tight fit in the dash its possible that the unit got a little stress and broke loose from the board .... if there is a white powder look in the display it probably bad... the silvery black in the corners is normal

Oct 28, 2007 | Sony CDX-M8800 CD Player

Not finding what you are looking for?
Sony CDX-M800 CD Player Logo

535 people viewed this question

Ask a Question

Usually answered in minutes!

Top Sony Car Audio Receivers Experts

Donald DCruz
Donald DCruz

Level 3 Expert

17129 Answers

Larry Stiles
Larry Stiles

Level 2 Expert

286 Answers

xxxxxx xxx

Level 3 Expert

4706 Answers

Are you a Sony Car Audio Receiver Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...