Acoustic Solutions LCD32NK750HC

[Dre892]

Hey,

This morning my now rather ancient Acoustic Solutions LCD32NK750HD failed to turn on. On power cycling the standby light flickers briefly before going out. I've had the back off and its fitted with a 17PW15-8 power supply (schematic attached).
On inspection the only obvious defects I can see are C859, C857 and C806 are bulging quite significantly.

C859 220pF 1kV and C857 4700µF 6V3 are both on the 3V3 rail. From what I can see the 3V3 is used as both the supply rail for the standby, and the gate source for the standby switching. Therefore I'm hoping replacement of these will resolve the issue.  

This appears to be quite a common fault with this power supply, but every other post regarding this fault recommends replacing C877 and C878. What would be your advice?

Cheers,
Dre

[Turnip]

Hi Dre,

Have a few notes on basic probs  - Vestel 17PW15 - 8
Variations – Some panels have socket PL807 fitted together with diodes D840 and D841 feeding DVB panel – have added extra bits to panels without and functions OK.
Power
1.    Goes to standby. Check caps C877 and C878 (15nf) near fets in top right hand corner – usually blue or grey in colour – tend to bulge when O/C
2.  Buzz from PFC area resolved replacing main cap C819(150/450)
3.  No blue S/by LED – no secondary voltages but 350 on main cap. Replaced C857 and C818 (both 4700/6.3)

All the best - Chris.

[sparky]

hi
d'nt forget to change the bulging
caps as well
dave

[Turnip]

Hi Sparky,

Goes without saying - Wilts does some nice 2200/16 (low ESR cheap but rather big) that I try squash into most situations - even those dual  4700/6v3 spots if cornered - well, 10.000 Muffs is sweet but guess low ESR is main consideration (Profilo dribbly 5v S/by cap thoughts abound)

Haven't seen a recent Profilo - holding breath - well a bit - Chris.