Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

[Behemot]

Hi guys,

got this one wih "not working" status. Checked +5V SB, there was as low as 2,5 V there. Swapped bulged crapxon and also one diode on its input for beefier - the former one measured OK, but was really burned badly from heating, basically all that part is. Than it measured arround 5 V, thats OK.

I tried to fire it up without fan, but got nothing, thought thats protection. But after recapping whole secondary and soldering in fan, I got still the same. Basically it slightly wheezes with no load, that's common for FSP I think. If I ground the green pin, the wheezing gets louder but I get no other voltage than +5V SB.

Measured quickly for short on secondary, there is none and also it does not go into protection mode (no clicking), so I think this is not the problem. So far I haven't changed the small caps, but I think they are hopefully in not so bad condition to prevent it from start with no load. Will swap them later too.

Any ideas what to check next? I have to go now, will shoot some photos later, so far you can grab som frome jonny for example: http://www.jonnyguru.com/modules.php...Story3&reid=84

[mariushm]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Check the thermistor under the secondary heatsink (and the transistor right next to it), see if the primary mosfets and secodary rectifiers are good (not shorted or open) ... go from there...

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

As I already stated, secondary bridges are OK. Also all transistors measured fine (including the small ones), all SMD diodes are OK and all optocouplers seem OK. The transistor with termistor over reads 6,17 kiloohms, I guess that's OK too.

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Success! Swapped two small caps near the baked +5V SB circuitry and it starts normally. Gonna swap one more in there and that should be it

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Bloody fucking hell, it just

One SMD zener crap is shorted, how can I identify it's values? It's tiny SMD crap with white and black (maybe grey?) stripes.

Found the schematics, it's the Z41 diode, any clue of what values may be there?


ADD// had a look into datasheet for DM311; it says it wants +20 V on Vcc and starts to work on at least +9 V. So would it be safe to use 20V zener diode?

[everell]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

The data sheet specifies that you must have at least Vdd 9 volts to operate properly and that 20 volts is the maximum. As you increase the loading on the +5vsb, the regulator will keep the voltage at 5 volts BUT the Vdd winding providing power to the DM311 chip will increase as the load increases. When the Vdd from this winding on the 5vsb transformer reaches the 20 volt maximum, the DM311 shuts down. That is how it protects your power supply. Usually those pwm chips have an internal zener which prevents the Vdd from going overvoltage - 20 volts in this case. If this chip does not have the zener internally, then the proper zener for you to use would be 20 volts.

Coming directly off the zener cathode, the trace also goes to and powers the Vdd to the main pwm chip. It also has a maximum voltage, and sometimes an internal zener. I think that 20 volts would be a good zener value for that also.

Since there is no current limiting resistor for that zener, I would recommend that you use at least a half watt zener ...... smt device OR kluge an axial component into the circuit. Since the zener is a protection device, it should not be necessary for ordinary operation. Most 5vsb circuits using the pwm chips that I have seen don't have a zener in that location. Beware that your power supply may have other problems which are causing the zener to blow. IMO just a cheap crappy part that died and shorted.

Which two capacitors did you change that helped it start working? That will probably give us a clue as to what is going on.

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

I changed C15 and C49. Than it worked. The last thing was probably accident - I didn't secured the PCB with screws so it may shorted somewhere. I have seen and heard huge spark

There is, however, resistor acting as limiting - the R42 on diagram. In my case, it is 2R2, not 4R7, but it is there.

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Now another zener is shorted, the Z42 on feedback. I am not sure why it is there on the first place, because on feedback, if there is over +4,5 V, the LM311 should know that, right? On the other hand, can the fototranstistor in optocoupler even produce such high voltage we would need zener?

Anyway, it's all getting very messy. I will likely dissolder it all and start working on separate board (but have to get it first ). I will start only with the Vcc and Vfb part as the rest seems good. Also do not want to mess with input 325V, it can stay on main PCB together with the very LM311.

[pdavid]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

I remember how much trouble I had when I first tried to fix a forton 60gly-gln whatever platform. Thanks to badcaps I fixed the standby but ultimately it turned out to be a dead ps233 supervisor.
I used that psu to mod another similar unit.

If it helps I can take some readings on some smd components while the the psu is live.

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Oh, thanks, seems to be same internals

[pdavid]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Okay, my scope tells me that the dm311's feedback leg gets 1.91-2.66V dcc. According to what the dm311's datasheet says I would choose a 5V zener
Before you replace the zener check c43, d40 and m3 opto. Maybe it got shorted somewhere on the feedback. Honesty I'm not a fan of this build because of the ps233 supervisor and the caps. I prefer forton's pnf units, despite the efficiency.
Hopefully you won't have much trouble fixin this though.

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

I heard that the PNF boards have even higher current on +12 V, so definitelly you won't tell BS used to be high-end

Anyway, I even desoldered half of the optocoupler and it still was shorted. As I said, it is really messy, it was darkened even before I started to operate there with my 125W transformer soldering pistol May be soldered somwhere to short but I just cannot find it.

For that reason I will just move all that section to a separate board and connect just wire here and there

[ipo3nk]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

hopefully this schematic help.

the z41 is 18v, & c41 100uf
theese parts & all secondary caps always fail after 3+ years operation.

thats why they only gave 2 years warranty. WTF!

[Behemot]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

Oh thanks bro, I am gonna definitelly use this. There is even more ore less whole PSU diagram in there, lets plagiate

[Ddsfadi]

Re: Fortron BlueStorm II (FSP500-60GLY) nothing but +5V SB

What is the value of z42 please can any one help