Vestel 17MB62 - 1 Sound issues.

[Turnip]

High folks,

Have one in where sound cuts to zero with a slight click. Remember someone on Quuq mentioned it was a known problem where C1077/1075/1076/1078 are suspect.

Had a look and although 1mfd/6.3v ceramic they are about 1mm long, and every time I took one off the board I lost it before I could check. Lost the whole lot in fact but no matter.

Noticed Ebay has some caps, but huge at 1.6mm long, so guess can fit 'em if can get them to stay still long enough to solder an end.

Wonder if anyone has ideas how to hold 'em down - Thanks - Chris.

[fix2003]

if it is not the caps it will most prob be the  TPA3113,and that will also be a difficult job to replace

bulletin
Change the value of the 4 Surface Mounted coupling Capacitors from 470nf to 1uf 6.3v they are in the Audio circuit U168 Ic .

C1075, C1076, C1077, C1078 . Pins 3 ,4 ,11 , 12 of the Audio Power Amp Ic

[Turnip]

Hi Vince and thanks,

Seems TPA3113 has less pins than an AS-15XX so maybe worth a go if it comes to it.

Mind you, there isn't much empty space down the bottom of the board as on a T/con, and I bet they've soldered it's underside to the board as there's heat to dissipate. Wouldn't bother but there's nothing SSB wise on Ebay for the actual set/screen/whatnot - Chris.

[bonesy]

Hi Bud,changing the caps always cures the sound issue,there was a mod kit issued by Sharp that contained caps & sound i.c. I've never changed the chip,just caps.It's the most fiddly job,but through microscope,a lot easier.CHS did the kit's,but as you know they've packed up.Might be worth trying
Ohm supplies,they do lots of stuff.

[Turnip]

Hi Vince,

Glad to know the caps usually sort it, but how on earth do you hold 'em down ?

With larger stuff I use a touch of S/glue but tend to suspect it might give soldering issues with smd caps this small - Thanks again - Chris.

[bonesy]

I've got some very good tweezers,I put a small amount of solder on one solder pad,hold the tiny cap towards opposite end,heat solder,slide into place,then solder other end.It does take me ages,hands not as steady as they use to be.

[cheeky2]

I know its an old post but just adding my advice after completing my first repair of these boards.
 I used a paste flux on the main board to hold in place the smd capacitor then with a pin held it at the middle whilst applied heat to one end. The flux gave it something to stick to instead of the needle tipped soldering iron. This was carried out under a microscope to align it and whilst soldering the components in place. I was pleasantly surprised how well it went after expecting the caps to disappear. I doubt I would have been able to achieve the results without the microscope as my eyesight is good but not that good for these very small components.

[Davy]

Is this the same board????

See this  video  https://www.youtube.com/watch?v=JV-v9CfH7ow

Check if headphone work and check speaker muting voltage - uses separate headphone amp. In my case the audio chip NTP8230 faulty, check voltages to chip.


Edit:
17MB65 Service manual  https://elektrotanya.com/vestel_17mb65.pdf/download.html


Dave