Acoustic Solutions LCD32762HDF stuck in standby

[Dansford]

Hi, I have the TV listed above with the power supply 17pw20.1 . The problem is that the TV does not turn on , the blue  standby indicator just dimms when tv is commanded on by remote or buttons. From what I have read the problem could possibly be the power supply board which needs repairing or replacing which is understandable and can be fixed by replacing some components.

I've inspected the board and none of the the capacitors appear to be bulging or at fault but looks can be decieving  . Can anyone help me identify the components at fault ? I can solder pretty well so if I can repair it would be great. I have basic tools i.e a standard digital multimeter, soldering iron etc.

Also components c878 and c877 on the schematic are described as 12n 630v and on the internet 15n 630v and according to the numbers 1.5uf 630v but it confuses me as I cant find them anywhere online  :wacko:, can anyone also help identify the correct component and a possible place to buy them. I like eBay  :cheesy1:

Thanks in advance  

Dansford.

[sparky]

hi
look at psu they are at the top left
 between heat sink and tx
look down at previous listing
sparky

[Dansford]

Hi, Thnx 4 reply Sparky. I know the location of the components, I just need to know if they are responsible for my specific problem. I dont want to spend time and money replacing perfectly functional components. Also finding those specific 2 polypropylene capacitors could prove to be an issue if i dont know the exact model numbers ? 

I've also read that other components could be at fault, is it possible to identify which specific component is responsible for this issue. (is it the c877 c878 caps ??)

Thnx  :happy:.

Dansford

[sparky]

you will have to take out and measure with
 a capactaince meter c877 c878

[stellaman]

There are four 85 degree caps on the P.S. that can give this problem . Had a similar fault and it was the Smoothing block faulty, the rivets were arcing.
Dave

[Dansford]

Hi Thanks For Replys.

Sparky: taken out c877, c878 and measured them, got no readings, possibly my error. I dont have a capacitance meter however took it to the repair shop and the guy said the two were reading correct measurements so were fine . I do have a digital and analogue meter tho :happy:.

Stellaman: would you perhaps know the values of the caps and/or their positions? Also not to sound daft but 'smoothing block'; is that the large snap in capacitor (150uf 450v - Neg). I was at electronics shop and he mentioned it but I cant remember which one  :wacko:.

I'll try to check for some faulty capacitors tomorrow, I started today and think I may have found some but I have to double check. When I get somewhere I'll post results  .

Thanks in advance for all help   :biggrin2:.

Dansford.

[stellaman]

Check C817/892/801/901. All are 85 degree caps on the power supply. Replace with 105 degree caps.

[Dansford]

Hi, Thanks Stellaman, those were among the capacitors I checked, and will replace them anyway :biggrin2:.

UPDATE: Just an update of what I've found so far. I've removed a few caps most likely to be at fault aswell as checking surrounding others, to be on the safe side, and I believe I've found some faulty/leaky capacitors.

Locations and values are:
C892 - 33uf 50v
C801 - 33uf 50v
C901 - 4.7uf 50v
C840 - 33uf 50v
C881 - 10uf 63v
C834 - 100uf 50v
C835 - 100uf 50v
and C819 (150uf 450v - Neg) - though I'll have to triple check this one!

I'll buy the caps and replace them asap, then I'll check the C878 and C877 just to be on the safe side, but if it boots up nicely no complaints  . Dont mind replacing the caps - just in case of errors as well as avoiding future problems, but my testing should have been accurate.

Dansford

[sparky]

i thought you didn't have cap meter 'if i was you
i would put 2x15nf new caps c878  c877 and try it

[sparky]

have you sorted this one yet

[Dansford]

Im waiting on the parts (which should be here in the next week or so) but I'll post an update just incase someone needs the info, or something doesn't add up .

Thanks

Dansford

[obagama]

Hi Dansford,

Did the replacement work for you. I have the same problems and I am wanting to order the same set of caps from rs component.

Please update the thread.

Thanks

[Dansford]

Hi Sorry, Ive been meaning to get back to this one.

I had to put this one on hold as I got a little occupied with other stuff. I think some of the caps I had previously tested were actually fine but my meter must have been playing up.

What I was planning to do was change these components and I am confident it would be fixed. I replaced some caps unfortunately I never got round to ordering the voltage regulators but I will do asap.

Sorry again to all those who were waiting... I'll post a general fix anyway - Common components to fail were/are:

Circuit Reference and Component description

Capacitors:

C877 ... 15nF 630v
C878 ... 15nF 630v

C817 ... 220uF 25v
C892 ... 100uF 50v
C801 ... 33uF 50v
C901 ... 4.7uf 50v

Voltage regulator:

IC829 ... 78L05

Hope this helps and I will post an update as soon as I have fixed it ... sorry again

Dansford

[tv tony]

why mess around, fit a kit!

[Dansford]

Hi, Those are pretty much the components that come in a kit.

I've just posted the components in more detail for people in need. Also some people might find it cheaper to obtain these components seperately. Either way I hope it helps 

Dansford