Silverstone ST1500 (+5Vsb shorted)

[new2019]

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?

I found about 3 small caps ,
1: in the AC side with 56uf 50v ( this is where the 32ohm short is there )
2: In AC side I cant see the correct uf and voltage but the cap looks small in size so lets assume its a small one for now .
3: In AC side a 220uf cap ( It looks small in size ) but can we consider this as a startup cap ?

Even though I removed the first cap that I have mentioned above the short is present .

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

which one should I get from these caps : for the replacement of 56uf 50v cap ?
1. Panasonic FC : here
2. Panasonic FM : here
3. Nippon : here
4. NCC : here

thanks alot

[c_hegge]

Re: Silverstone ST1500 (+5Vsb shorted)

If you must use ebay for caps, use egekecu, as he's one of the few who sells genuine caps, so in your case, the Panny FCs or the Nippon Chemi-Con LXY caps would be your best bet, depending on the size you need. The FCs are 8mm diameter and the LXYs are 6.3mm diameter.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

If you must use ebay for caps, use egekecu, as he's one of the few who sells genuine caps, so in your case, the Panny FCs or the Nippon Chemi-Con LXY caps would be your best bet, depending on the size you need. The FCs are 8mm diameter and the LXYs are 6.3mm diameter.

Thanks mate , but before I place the order how do I know the cap that I have is bad ? I checked for short and it shows OL ( infinity) and then I charged it in diode mode and checked the voltage and it seems to store charge and release it when checked in voltage ( it gradually decreases ) .
However I guess this must me the start up cap .

[c_hegge]

Re: Silverstone ST1500 (+5Vsb shorted)

^
Without a an ESR and capacitance meter, you can't test if a cap is in spec or not.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

Thanks mate , il place the order and see what happens .
Also which one is best to get ? If you made the choice between two ? which one would you take ? I dont know much about caps , you guys are pro.
I really want to get the best one for this so it can last long , size is not a problem because there is plenty of space for that cap .

Also what is this stuff , that I have circled in red ?

Thanks mate

[stj]

Re: Silverstone ST1500 (+5Vsb shorted)

thats a current limiter.
dont touch it when the supply has been on because it gets HOT

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

thats a current limiter.
dont touch it when the supply has been on because it gets HOT

Thanks mate , I ordered the Nippon capacitor .
To check the psu, shall I buy a cheap capacitor locally and power it on ?
Because its going to take a month to reach me.

[Agent24]

Re: Silverstone ST1500 (+5Vsb shorted)

Yeah you can use cheap capacitors for testing as long as they are Low ESR, don't use general purpose or the PSU might still not work and you think it's something else even if the capacitor was bad before.

Just don't leave cheap ones in there for a long term fix, they won't last very long.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

Yeah you can use cheap capacitors for testing as long as they are Low ESR, don't use general purpose or the PSU might still not work and you think it's something else even if the capacitor was bad before.

Just don't leave cheap ones in there for a long term fix, they won't last very long.

Sure il ask them for low esr caps (dont know if they will understand what im asking lol )
As long as its not going to cause a big short , im just going to test with it. But as you mentioned above they can be bad earlier , so I have to consider what im going to do.
OR wait for the good ones to arrive .
THanks mate

[Agent24]

Re: Silverstone ST1500 (+5Vsb shorted)

If they don't know what Low ESR means then they likely do not sell them. If you can get the brand and series of what they sell you can look it up online though and find out exactly what they are.

Nothing will blow up if the capacitors aren't good enough, it just won't work... But the problem is - if the capacitors in the PSU now are bad, and you buy ones that aren't good enough, how do you know which is the problem?

If you buy good Low ESR capacitors and it still doesn't work, you know it's not the capacitors.


Edit: You don't really *need* low ESR capacitor for a startup capacitor, but they will last longer.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

If they don't know what Low ESR means then they likely do not sell them. If you can get the brand and series of what they sell you can look it up online though and find out exactly what they are.

Nothing will blow up if the capacitors aren't good enough, it just won't work... But the problem is - if the capacitors in the PSU now are bad, and you buy ones that aren't good enough, how do you know which is the problem?

If you buy good Low ESR capacitors and it still doesn't work, you know it's not the capacitors.


Edit: You don't really *need* low ESR capacitor for a startup capacitor, but they will last longer.

Yea , most people here doesnt know much about repairing electrical stuff, so when I find it il have to look online for specs .

yes if the one that I buy is same as the one that I have I will see zero result .


Thanks for pointing out that normal ones would do for startup , otherwise I would have been searching for one all day in this city lol .
I dont care how long they last because I already ordered good ones hehe .
DOnt know if these local sellers are selling cheap chinese ones lol .
Il get them and post back .
Thanks for your help.

[predator0357]

Re: Silverstone ST1500 (+5Vsb shorted)

which one should I get from these caps : for the replacement of 56uf 50v cap ?
1. Panasonic FC : here
2. Panasonic FM : here
3. Nippon : here
4. NCC : here

thanks alot

I think that u need to order not only by size to fit like original, cuz when the cap is biger in size the cap is lower in esr and bigger life span, so if its not fits as original and u may need to solder it higher on the pcb but like i said bigger in some cases is better.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

Yea ! But I ordered the Nippon already , but it has longer can than the one that I have now , so it will have less esr .
Also I bought one locally it was a 47uF 50V can I install it and test ?
The guy didnt have 56uf cap . But he had a 64uF 100V , but I bought only 47uF 50V , can I go ahead and test ?

[Agent24]

Re: Silverstone ST1500 (+5Vsb shorted)

47uF should be OK, it's pretty close.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

47uF should be OK, it's pretty close.

Thanks mate , il start the soldering and report back.

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

I tried but still the same ? I used a dvd rom for load ? I tested without connecting the earth wire (green one near the AC power socket , im not telling about the output PSON wire .

[Agent24]

Re: Silverstone ST1500 (+5Vsb shorted)

I re-read the thread and I'm still not sure what exactly you think is shorted in the primary side. If there is a short there the fuse would blow.

Between which components\pins did you measure the short? Hot ground and pin 6 of that 8-pin device? What is your reason for checking there? Can you give the part number of that device?

Do you at least get power to the primary filter capacitors?

[new2019]

Re: Silverstone ST1500 (+5Vsb shorted)

There is no full short , but a lil short .
I plugged the power and checked for voltages but there was 0.01V near the cap that I replaced , also I checked the +5Vsb and found the reading was 0.01V , both the reading was little fluctuating about 0.01 - 0.02 . I guess the reason why there is not potential difference because there is a short .

if you look at the first pic I posted you would see I have wrote in yellow letters , yes those pins/lines are shorted to hot ground with resistance 32ohms .
Yes the pin 6 is the same line where two caps parallel( one is a ceramic cap and other is the cap that I replaced today ) and a resistor in parallel to caps .

part number of that device is: 200D6
PCOQ

can you show which one do you mean by primary filter capacitors ?
do you mean the big 4 caps that I have shown in post 26 ?

I connected to power and measured the potential at those big caps , they seem to be 298V (in DC mode multimeter) . It slightly increases to 300V and decreases to 296 .

There is no output from the powersupply in any rails .

[Agent24]

Re: Silverstone ST1500 (+5Vsb shorted)

That chip is an NCP1200, which looks like your 5vSB controller. Pin 6 is its Vcc pin which is derived from an internal regulator that gets power from the main filter capacitors, and decouples with a small capacitor. (See example circuit page 2 in attached datasheet)

Pin 6 showing low ohms to ground does seem suspect. There are two capacitors (ceramic and electrolytic) on pin 6 to ground? The electrolytic is the one you changed?

Did you try testing the ceramic one for being shorted?
Pin 6 should have around 10volts on it when running, do you have this?

Pin 8 should have 300v or so from the primary capacitors.


Yes the primary filter capacitors are those 4 big ones rated 420 volts