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Power Supply Board of Beovision 3 ( same as Avant 32 Real Flat)

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RaMaBo
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RaMaBo posted on Sun, Aug 18 2013 6:29 PM

Hello,

 

i have a Beovison 3 MK I (8800) which suddenly had a fault with the power supply.

The TV was switched off with the mains switch (lower left under the frame). When it was switched on the standby LED didn't come on and also no reaction on pressing TV, DTV, VMEM or DVD button.

Removed the uper and lower back to check the mains fuse, which was okay (what else Crying ).

So i checked the function of the mains switch, the power cable and everything else until i reached the input of the main power supply board but everything is fine.

So i started to remove the powersupply board of the TV to get better access to the components on the PCB. All Elecrolytics were checked for Capacity and ESR but all values are fine.  A visual inspection of the board gave no sign of a damaged part. Verified the big rectifier at the input but it gave correct readings with the diode test of my multimeter. Also checked the big diodes at the low voltage part of the  switched power supply but they are also well.

Has any ever repaired the power supply board with this or a similiar failure? The power supply seems totaly dead, as if it won't start to oscillate at the primary side to produce at least the 8V Standby voltage.

Any help appreciated because me and my FS love this nice set and it's quality in picture and sound!

 

Ralph-Marcus

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bramble
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Had the exact same fault with my beovision 1, the power pcb failed unable to get new one . B&o say they no longer kept spares due to age of product ...only 2006 model, no doubt you will get the same as with the bv3, .....I just hope my bv3 keeps going, good luck

Beovision 7 40 mk 5 ,beovision 6x3,   beosound 3000, beogram 3300 , 2 x lc2, 2 x beocom 1401, beocom 6000 x 2,  5 x beo4, 

, 4 x beolab 4's, form 2, h2, a2,a1 and a beolab 2 😀😀

 

 

 

ipaul
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ipaul replied on Thu, Aug 22 2013 2:52 PM

Hi, i am not sure if i understand your measurements correct (as i assume you only measured without the mains power connected) but nevertheless this may be of help (but you may not like it...).

Btw, a BV1 has totally nothing to do with a BV3, a whole different chassis, parts, etc.

I assume you're confident enough to do some work inside a tv (it seems): i'd start from ''back to front'' in this case:

Just close to the microcomputer (on the board witgh the scarts, in the metal housing) you'll see 3 or 4 relatively small elcos.

When the tv is switched on (on standby, regardless if you see a standby led) there should be 5 Volt on these, at least on 2 or 3 of them.

This is the power for the microcomputer, if present: it seems the computer has a (not uncommon) problem, could be the ROM/RAM but also the upc itself (and that is the end of it).

If the 5 volt is not present at all in that area, indeed work backwards with checking power.

In my experience the power supply rarely dies in these sets, on the other hand i did come across these upc troubles...

Be warned that in standby, you'll measure very low voltages on the output caps on the powersupply module, the 8V will be present on (a part of) the 150V line and some switching takes place when the tv goes from standby to ON. (the 150V line goes from 8V to 150V and the 8V circuitry will be supplied from a different section of the power supply).

So in standby, you should find 8 volt on the 150 volt line out of the powersupply module.

Anyway, checking the 5 volt (and i think one is 8 volt) on the caps close to the upc is quite easy and will tell you a lot more...:), hope this is of any help.

RaMaBo
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RaMaBo replied on Thu, Aug 22 2013 4:35 PM

Hi,

 

thank you for your hints and tips!

I will try to check the next few days if there are 5V at the CPU elcos and 8V at the 150V lines during standby.

You are correct that my measurement was done without the mains connected. Thanks for the hint of the 8V going up to 150V when tv is switched on. Prevents me from getting a surprise :)

Will report back if i did check the 5V and 8V. Hopefully the 5V are missing and 8V is available.

 

Ralph-Marcus

RaMaBo
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RaMaBo replied on Mon, Aug 26 2013 12:12 PM

Hi,

 

i was a bit successful in so far that i mounted the powersupply board in the TV set and got all connectors mounted back in place. After that i connected the mains cable to the TV and tried to meassure the 8V Standby but with no luck. Checked all other Pins of the two cables going to the mainboard but no voltage came out. Okay i know i have forgotten to switch the TV on with the mains switch Whistle

Switching the TV on gave me the standby light nearly immeadiately. This made me wonder because nothing was changed but i gave it a try and grabbed the Beo4 pressed TV and nothing happened. eyebrow's moved around and pressed TV again. Now degaussing took place and shortly the electronic curtain moved. Let the TV run for a few minutes and finally put it in standby again. Switched off at the mains and after one minute repowered the set and activated it with the remote.

It worked like a charm so mounted the two back covers and front frame after switching off the TV.

Connected all cables and started the TV for the sunday evening event Smile at around 18:30.

We enjoyed the evening until the TV decided to shut down without a sign and no more standby light around 21:30. It just switched off no banging sound or flashing,nothing. Switching off and on at the mains switch changed nothing to the standby light or anything else so i let it switched off for a good half an hour.

Switched it on at the mains switch and the standby light came on. Same procedure as before TV could be switched on with the remote. checked the TV Error Log in the service menu but there was no entry.

 

After reconnecting the power supply board yesterday i checked the voltage of the Lithium battery on the mainboard which gave me a nice 3.06 Volts reading which declares it should be replaced but i don't think this has anything to do with shutting off after ~ 4 hrs of watching TV at a real moderate room temperature.

So what else could be the next step to get this fixed. Does anyone had the same failure before (ipaul maybe ) and can give me a hint?

 

Thanks in advance

Ralph-Marcus

ipaul
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ipaul replied on Wed, Aug 28 2013 9:18 AM

Hey, in a way still the same advice: when the tv shuts down or seems to be dead, check if there's 5 volt present in the microcomputer region.

i have to say this on and off working and not working and no errors, to me it still sounds like a problem with the cpu :(, the presence of the 5 V there will tell you more...

RaMaBo
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RaMaBo replied on Wed, Aug 28 2013 9:52 AM

okay i will do so next weekend ( because i'm busy this week) and check the 5V if it shuts down itself will report back next week.

 

Ralph-Marcus

RaMaBo
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Okay had again the pleasure of watching TV for 4 and a quarter hours then it shut down. Did as Paul said and got the 8V Standby at the power supply connector and 5V at the microprozessor board while the standby LED was off.

Switching the set completely off, waiting abou 1 minute and switching brought it back to live.

Any chance to find out whether it is the ERPOM or the FLASH chip except changing one after the other with a new one with the copied content? Or can it also be the CPU and noone knows what the cause is?

 

The actual sofware revision is:

06 IC3  (AP)     6.41

06IC2  (IOP)   17.1

EEPROM Version   5

 

Ralph-Marcus

ipaul
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ipaul replied on Mon, Sep 2 2013 9:47 PM

You see:  a common misunderstanding is : no standby led means no power...

but (unfortunately, in a way) now you can pretty safely assume your power supply is ok.

indeed: somewhere in the cpu area it seems to go wrong, eprom, ram, rom...or the cpu.

RaMaBo
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Thank you for your valuable hints so far !

Do you think it makes any sense to copy the existing EPROM and FLASH chip to replace them or is this a stupid idea just wasting time and chips? Do you have any hints or experience what it is most probably or was it your list of possible defect parts a kind of enumeration?

I really would like to get this set repaired because it safes me from lifting the TV and replace it by another heavy one Whistle

 

Ralph-Marcus

Guy
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Guy replied on Mon, Sep 9 2013 10:07 AM

I don't want to hijack your thread but I wondered if you had managed to get any further solving this problem.  My BV3 developed a similar fault a few days ago after a possible power surge when our iron tripped the house power supply.  It now shuts down after a random period of time, from a few minutes to a few hours.  The green standby light stays on, and I have to switch the TV off at the power switch for a while before it will re-start.  Unlike yours, I do get some fault codes as follows:

Hence I am very interested in finding out your solution if you have one, or any advice from elsewhere.

RaMaBo
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RaMaBo replied on Wed, Sep 11 2013 11:36 AM

Hi,

had not much success up to now, it got even more worse. The 'On time' is going down from ~4 hours to ~1 hour. Tried to reseat the flex connector cables from the mainboard to the µp Board.

 

Your BV had problems with the communication to the modules itself. The errors are I²C communication errors between the µp and some modules. Those error codes won't help much because they all happened at the same time.

You can press <OK> in the view to clear the error codes. and try to see if they reappear the next time.

 

 

 

Ralph-Marcus

Guy
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Guy replied on Thu, Sep 12 2013 1:03 PM

Many thanks for the response.  I did try clearing the codes before but it still shuts down a while later.  It also sometimes loses the 'connections' settings for my two STBs so I have to start the TV using TV and re-set them.

I am tempted to try and get it fixed but not sure if it will be cost effective ...

RaMaBo
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RaMaBo replied on Mon, Sep 16 2013 3:32 PM

Did you have success clearing the codes? Was the error log empty afterwards?

After the failure happened again where the same errors logged in the error log?

Ralph-Marcus

Guy
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Guy replied on Mon, Sep 16 2013 7:49 PM

Yes I could clear the codes but the same errors did re-appear.  The TV is still switching off after a random time period, and I also see a little bit of blue colour leakage after a while.

I have just ordered a 'second life' 6-26 as a stop-gap solution, and am trying to decide whether to give up on the BV3 and start saving for a 7-40 Mk 4! 

 

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