notebook ac adapter pulsing?

First, half a volt isn't a serious problem for most notebooks. Check for other problems, too.

Second, don't trust 'capacitor check' on the capacitors unless you get both capacity and ESR (resistance) readings. Replace the output filter capacitors as a first step (it's cheap, you have to desolder 'em to test anyhow).

All the components must be suspect, because this kind of regulated supply is a single feedback loop, if that doesn't work.

Exactly what does this mean? What are you measuring it with? What are the actual parameters of the "pulse"? which

Huh? You're saying the notebook boots fine from battery?

Assume you checked the caps by pulling them and checking for Capacitance and ESR? First cap is the most stressed, but the second one masks that effect if you don't disconnect 'em. Line filter cap can also be a problem...limit cycle oscillation when the regulator goes in and out of saturation. Don't forget your isolation transformer if you try to measure it with a scope. Best way to check filter caps is to put a load and a scope on it. Bad caps will be obvious. If it's not completely dead, it's almost always bad caps.

Thank you besides pulsing you can hear clicking in same rhytm,probably from transformer since lk837 seems to be optocoupler. With (non notebook) load output goes down to few volts!!There is also a controller chip LT 2669cp if I see ok

my mistake the pwm controller is ob2269