Silverstone ST1500 (+5Vsb shorted)

[new2019]

Hello everyone , I have some problems with my psu.
The psu is not powering on (no green light or fan not spinning)
I opened the psu and found short on +5Vsb , I removed all caps in that line and still short is there (its not a full short , its a lil short like 23ohms not 1 or 2 ohms)
Also I found another short in primary circuit its also about 34ohms .
I examined all components and didnt find any blown caps or blown diodes.
Board has zero burn marks its fresh . Also this psu has a short circuit protection , when it finds a short it will shutdown and wont come up until short is gone .
please tell me where I can start my testing procedure from now ?
Thanks for your help!!!

[budm]

Re: Silverstone ST1500 (+5Vsb shorted)

GOOD, CLEAR Pictures and test points where you see all these low resistance readings will help us to help you.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

Ok I took the pics , il upload it now .

[stj]

Re: Silverstone ST1500 (+5Vsb shorted)

probably a load resistor or a shorted diode / ceramic cap

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

I have marked the shorted points . other than those places I dont find any short .
il upload more pics later , it takes alot of time to upload.
ps: the short goes up to the small secondary board (the one I have showed in single line red , which has many pins in a straight line ) .

How can you check if the load resistance in gone ? I checked the resister that is connected between live and neutral wire , it has about 200kohms , also there are two filter caps connected to it ( all these stuff are out of the board ) these are present near the power socket.

[stj]

Re: Silverstone ST1500 (+5Vsb shorted)

you see all those resistors that say "201"?
those are 200ohm and they are in parallel - that's your 25ohm

your actual problem is something else - maybe startup capacitors.
what small 4.7 to 47uf caps are on the top?

[selldoor]

Re: Silverstone ST1500 (+5Vsb shorted)

Picture from the top straight on and acouple from each side?

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

@stj thanks for clearing my big problem , I thought that line was fully short .
so 10 200ohms resisters in parallel is about 20ohms that makes it correct ( because the multi would read some what higher than real ) .

can you pin point on what area I should look for start up caps ?
Also I connected this to power got a small fluctuating voltage like 0.01v - 0.02v.

thanks mate

[selldoor]

Re: Silverstone ST1500 (+5Vsb shorted)

Just a couple of points - can we assume you are trying to start it with a jumper on green to ground?
Some supplies need a load to start so can you attache something the 12v- Hard drive?
car lamp? and something to 5v

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

Picture from the top straight on and acouple from each side?

here they are !!!

@sji : can it be the short thats on the primary circuit that I have shown in yellow ? I checked the rectifier and I didnt find a problem with it .

Can I suspect any transistors ?
Also In the primary circuit I found two resistors shorted ( fully short )

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

Just a couple of points - can we assume you are trying to start it with a jumper on green to ground?
Some supplies need a load to start so can you attache something the 12v- Hard drive?
car lamp? and something to 5v

I shorted green wire to ground and connected a dvd rom , also tried a sata harddisk .
Nothing comes on . But I hear a sound near the filter capacitor near the power socket , then I removed it and tried to turn on but still nothing.

[stj]

Re: Silverstone ST1500 (+5Vsb shorted)

that's packed in so tight i cant see anything!

i'd just replace all the small caps with FR or FC series and see if the standby voltage starts.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

that's packed in so tight i cant see anything!

i'd just replace all the small caps with FR or FC series and see if the standby voltage starts.

do you mean the outputs secondary caps ? what are FR and FC series ?
Will it be related to caps ? I find a short in the primary circuit about 32ohms .
I cant figure from where it comes.

[stj]

Re: Silverstone ST1500 (+5Vsb shorted)

panasonic FR and FC series caps - very high quality stuff.

i'm not really talking about the output caps, i'm refering to small ones - under 100uf probably that are related to the actual control circuits.

most psu chips have what we call a "startup cap" that is responsible for kicking it into action when the power is applied.

because they are small, they dry up inside - the official minimum life on such small caps is only 1000hours.
1000/24 = 41 (days!!!)

[stj]

Re: Silverstone ST1500 (+5Vsb shorted)

about that 32ohm, is it on the ac side of the rectifier, or the dc side?

is it the same with the meter wires the other way around?

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

panasonic FR and FC series caps - very high quality stuff.

i'm not really talking about the output caps, i'm refering to small ones - under 100uf probably that are related to the actual control circuits.

most psu chips have what we call a "startup cap" that is responsible for kicking it into action when the power is applied.

because they are small, they dry up inside - the official minimum life on such small caps is only 1000hours.
1000/24 = 41 (days!!!)

I ordered this stuff: here

ok il replace all those caps , what do you think about the ceramic caps ?

its a shame to have such low life .

Its on the AC side thats what I meant by primary side ( im sorry for mis typing)
Even though I change the poles of the multimeter wires it keeps the same.


On the 10th post 3rd pic , can you notice two big green caps (which looks in box shape and has a black wire) can it even cause a issue like this ?

one more thing: I got a buzzing noise when I connected to power in this part: here
then I ordered this , up to now I didnt install it , will the psu power on if I install this ? also why do they call this a relay ?
thanks mate

[selldoor]

Re: Silverstone ST1500 (+5Vsb shorted)

If you have ordered it is too late but we dont often recommend ebay for caps - many fakes around. That seller also has feedback on those caps -sent inferior ones.
Also the startup and small caps are often 50v did you get 10v from the caps you are replacing, and another thing, they are 11x8mm - will they fit?

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

but its a $ , I bought it because when I removed one of the 470uf cap one leg broke off , so I thought this would do the job it was also a 10v 470uf cap , I have small question about replacement cap , as a replacement cap it should have same capacitance but it can have higher voltages right ?

Where can I get good ones ? I normally use ebay for all electrical stuff , because I cant find anyone who ships worldwide .

If anyone could fix this psu I can pay for work and parts . Because I spend over 250$ few months ago to buy this , I cant waste any money on new psu so im kinda trying to wake this up.

or il try to fix it my self with all your help .

[selldoor]

Re: Silverstone ST1500 (+5Vsb shorted)

Yes its a $ but look at the work involved in fitting it. So you only want to do that once!?

Yes you can use a same uf higher voltage ( usually one step)
You can also often use 1 step higher UF.
NEVER use lower uf or lower voltage (unless you really know what you are doing)

I dont know where you can get good make caps in Srilanka and I have not seen many
Srilankan members on this forum. International sellers are Digikey Mouser RS components , Maybe Farnells and there maybe some in Australia that ship to Srilanka

'What are the part numbers on the controller chips on the riser board?

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

lol I didnt read about size , also I dont have a caliper to check the sizes of the caps ,
I have to see how its going to fit , but next time I'm going to order stuff after checking all compatibility .

The numbers that I see are:
one the big chip: PS232S
B08641A1F
on the small chip: WT7518 S144
916 J29AB
Both of these chips are there in the same riser board .