FSP300-60 rev.2

[fulfunc]

Help people !!

I have salvaged an fsp300-60 that I am currently cleaning up and refubishing to work as a simple desktop power supply for +12v, +5v, and +3.3v
generally going ok BUT troubles with +12v and identifying what the 3 trimmers are for: VR1 is right beside the PS-OK wire, VR2 is righ beside +3.3v wires, and VR3 is at rear of board near fsp3528 chip.

I haven't been able to find any schematics for this unit, just spec sheets.

+5v is giving me +5.24 --- great
+12v is giving me +11.2v ---jumps to 11.6 if I disconnect the fan

any ideas on what is happening and what those trim pot are specific for??

[stj]

Re: FSP300-60 rev.2

did you recap it?

[Per Hansson]

Re: FSP300-60 rev.2

How much load do you have?
Older group regulated PSU designs require a minimum load per rail...

[everell]

Re: FSP300-60 rev.2

What mother board are you using? Did you measure the output voltages with the power supply attached to the mother board or just running not attached to anything?

[fulfunc]

Re: FSP300-60 rev.2

I am running it as a desktop standalone with a 52 ohm 5 watt load across the +5v .

Measurments all made with Fluke DVM at front terminals ---
I have removed the output cables and replaced them with simple terminals and a power switch mounted where the output cables used to be.
I also put an LED across the +5v so that I can see when it is active.
Changed fan to Fractal R2 quiet fan -- controlled by thermal controller that FPS called their Noise reducer.

This was a unit that I salvaged from someone's scrap to make a standalone power source for general electronics activities, including teaching my grandchildren ....

[Per Hansson]

Re: FSP300-60 rev.2

You have to have a higher load on +12v for it to be stable.

[fulfunc]

Re: FSP300-60 rev.2

Hi guys !!

The answers to your questions --
main chip is an FSP3528 310 1971C

all measurements are made at the front output terminals using my Fluke 87 and confirmed with my Fluke 37 -- both are calibration traceable -- I needed them for my work servicing instrumentation and process control equipment.

VR1 has markings "102" and is located beside the PG wire and near the PS-ON wire

VR2 has markings "202" and is located beside the +3.3v output wires, and is connected to the +3.3v sense (brown wire)

VR3 has markings "501" and is at the rear close to the AC input

I am assuming that the +3.3 sense is regulating the +3.3v and +5v lines.

I do not know what the VR1 is for unless it has something to do with the power good level and timing.

I am guessing that VR3 likely has something to do with the overall gains to regulate the +12v, +5v, and +3.3v, but I could be totally wrong.

This is one of those situations were a schematic and/or service manual for this old beast would help tremendously.

I have sent a request to Sparkle Power, noting that this is an old obsolete model, out of production, but useful for us legacy boys.

It also has the termination points for an OCP panel, which I know nothing about, but could prove useful to someone.

Mike

[fulfunc]

Re: FSP300-60 rev.2

Per Hanson ;; outputs are stable as a rock -- the cooling fan also draws on same +12v power -- if I remove fan and load resistor then the +12v drops it moves.

I have left unit running and watched stability for over 12 hours -- perfect

Specs call for all outputs to be stable at no load as well as with load ...
They also suggest that with +/- 5% as quoted regulation, the current readings would be within spec JUST BARELY.

I look at the unit as having had the benefit of a "long burn-in", so it should be stable and settled wherever it is -- now it is ready for tweaking to desired output levels

Mike