Non ATX SMPS Question

[Tinkerer]

Hi, I figured this would be a good place to come to ask a question like this.
Long story short, I delved into computer power supplies recently and have learned quite a bit, with that said, I will get straight to the point:
http://320volt.com/en/dell-sa145-3436-uc3842-lm358-145w/
I have a practically identical power supply as the one in the link.(for all intents and purposes)
My question here is what would I look at if I wanted to adjust the output voltage?
As it currently stands, this particular SMPS requires a load across the 5v and 12v in order to run.(otherwise it of course simply cuts off)
This also does not have a soft start, the switch is a direct on or off switch, not really any standby.
Now, I am not sure if I am right, but I believe the LM358 is involved in over voltage protection.(partially at least)

If there isnt anyone who easily knows the answer, just being pointed in the right direction would be great too.
(if anyone was curious, I got this PS out of a 1996 Gateway 2000; was somewhat suprised by a lack of electrolytic caps, 3 total, ignoring the 4 5/12v output filter caps and the 2 rect. mains caps, just means I would have less to replace)

Offtopic question, I have wondered, just how long would it take caps like the rect. mains caps(200v 470u) to dry out anyway? I would assume quite a bit longer compared to the smaller ones.

[c4757p]

The LM358 isn't involved in OVP, it is the regulator. IC6 (TL431) provides a 2.5V reference, and IC5B (LM358) compares this to a feedback voltage derived from both the +12V and +5V rails. You'd have to recompute the entire feedback network R39/R40/R41/R42/R43/R44, which is all interdependent.

IC5A just controls the power-good output.

As for OVP, you have SCR2 (TYN112) tripped by either of the two Zener diodes Z4 and Z5. The OVP is set very tightly - if you increase the voltage even a bit, change these or it will trip.

As far as I can see, it does have a crude soft-start: TH1 is a negative temperature coefficient thermistor, which will limit the input current until it heats up.

Offtopic question, I have wondered, just how long would it take caps like the rect. mains caps(200v 470u) to dry out anyway? I would assume quite a bit longer compared to the smaller ones.

A very, very long time if they are good ones, sometime tomorrow if they're not.

[Tinkerer]

Thanks for your response. That helps a bit. I had an inkling about the feedback network resistors you mention but was hoping it would be simpler, not that basic resistor/voltage calculations are that terrible.(I had already replaced R41-44 with a pot and yes, the output is tightly controlled)

As far as I can see, it does have a crude soft-start: TH1 is a negative temperature coefficient thermistor, which will limit the input current until it heats up.

I did not realize you could consider that a soft-start but I otherwise knew the purpose.

A very, very long time if they are good ones, sometime tomorrow if they're not.

As suspected, but never could find a solid answer on it.