ADA converter flash at power on but no start

[r2d2]

Hi all,
having issue with a Digidesign 888-16 ADA converter
at the power on the lights on the front panel start to flash on-off fast
and is audible a slight click synchronized to the lights flashing (on),

rarely after several seconds of flashing the unit stop in correct power on status
and work normally,

almost certainly the problem is caused by the psu,

please there is a specific component of psu that degrading/spoiling is the cause of this "symptom" ?
Any about is welcome,
thanks.

 

[Khron]

Electrolytic capacitors. In particular likely the smaller one on the primary side (so-called "startup"-capacitor).

 

[r2d2]

Electrolytic capacitors. In particular likely the smaller one on the primary side (so-called "startup"-capacitor).

Thanks for post and tip !
Soon i post images about the psu for more easy way detect the possible faulty parts .

 

[r2d2]

Electrolytic capacitors. In particular likely the smaller one on the primary side (so-called "startup"-capacitor).

Hi in attached the psu unit image.

 

[Walrus]

As Khron said try changing the capacitor between the PC111 opto isolator and the other 8 pin chip.

 

[Khron]

And is C18, bottom-left in the picture, a bit domed?

 

[r2d2]

And is C18, bottom-left in the picture, a bit domed?

As Khron said try changing the capacitor between the PC111 opto isolator and the other 8 pin chip.

Thanks for post !

A bit a "PTA" (no best design for a more than 3000 bucks unit, when new..),
for get out the psu, the mainboard have to be pulled out,

and found in the back a "semi-burned" pad of the "big" 330ohm resistor,
as showed in the attached image,
(umpteenth fu.... in......that mounts units on racks without leaving space for ventilation)

about the "C18", seems it is a bit doomed,
so time to get capacitors replacement,
and check if the 888 back to run properly,
for let you know here about it.

 

[Khron]

and found in the back a "semi-burned" pad of the "big" 330ohm resistor,
as showed in the attached image,

That looks like part of the RC snubber across the flyback transformer's primary winding.