470 µf 200 V JEE

[cybe]

Dear Everyone,

A friend of mine wishes to fix a power supply he has. It has two JEE capacitors: 470 uF and 200 V which he says show signs of overheating and wax having come out of one or both whilst they were overheating.

The other numbers on the other side of these components are:-

CE.W IM 0346 85º C

They are cylinder shaped 35mm high x 20mm diameter.

JEE is listed here as a bad cap, so he should probably be able to fix the power supply by repleacing them?

He is also wondering if they should be 250Volts, not 200Volts for the U.K. Mains voltage?


I would be greatful for some help on this, I had difficulties navigating the hardware sites listed here: https://www.badcaps.net/forum/showthread.php?t=613 to find just the right capacitor.


thank you,

Staffan

[Per Hansson]

Re: 470 µf 200 V JEE

The "wax" is hot glue put under the cap to stabilize it. Generally the large bulk caps never fail

200v is fine because the circuit uses voltage doubling so the two caps are used in tandem and thus can whistand 400VAC

Whithout pictures it would be difficult to say really what is wrong, what is the problem he is experiencing? And more importantly how does the small capacitors on the secondary side look?

[cybe]

Re: 470 µf 200 V JEE

Dear Per,

Thank you for your swift reply.


The capacitors have discolouration on the outside as from overheating and the hot wax has obviously overheated and run.

The power-supply stank the room out with a similar smell to the burning wax in a transformer and stopped working.

On inspection I can see no signs of any overheating on any of the transformers or any other part, except the two caps mentioned.

Where is the secondary side located please?

[cybe]

Re: 470 µf 200 V JEE

According to the FAQ the secondary side is:

Output Rectifier & Filter
Though the output rectifiers are usually two rectifiers in one package, in the most common topology, the two devices have different functions. One of the devices conducts during the “on” part of the square wave from the transformer, charging the inductor. The other rectifier conducts during the “off” time, providing a current path for the discharge of the inductor. The output inductor and output capacitors form a filter that convert the square wave to a DC voltage. The current through the inductor has two components - the current to the load, and the charging-discharging current super-imposed. The current through the filter capacitor(s) is the inductor charging-discharging current plus some transient currents due to large changes in the load current. Since the ripple current through the capacitor(s) can be several amps rms, low impedance capacitors are absolutely essential. This side of the P/S is commonly referred to as the “secondary” side.


Not so sure that helped me much since I'm not very good at these things. Will mail my friend and see if he can locate the capacitors on the secondary side...

[jonnyGURU]

Re: 470 µf 200 V JEE

JEE!!!!

JEE is listed here as a bad cap????

Uh oh....

[willawake]

Re: 470 µf 200 V JEE

the list refers to 105oC caps not 85oC

[yanz]

Re: 470 µf 200 V JEE

yup. the lower voltage ones (10-16v) are crap. pure crap. im not saying that the higher voltage ones are good, dont have real experiences with the hi-pot ones.

[Per Hansson]

Re: 470 µf 200 V JEE

The secondary side is where you have DC voltage, it is where the ATX cable goes on the PCB... You will also have allot of small caps here, each on 3.3v 5v and 12v also 5VSB

To say if the Primary 200v JEE caps have really failed or not we will need to see pictures, but as I said it is quite rare, and if they indeed have the rest of the PSU will probably be damaged too

The reason these high voltage 85°C caps rarley fail is because they are simply less complex to construct, so even the crap manufacturers like Rulycon (Not Rubycon!) and Fujjihu (spelling) can get it right (where as their LOW ESR 105°C caps most of the time fail within 18 months if you load the PSU to the specified ratings...)

[cybe]

Re: 470 µf 200 V JEE

Don't think my friend has a digicam.

Here's some further details from him. Worrysome stuff. I wonder how many fires PSU:s have caused? I always unplug my machines when they are not in use.

If it helps with the diagnosis to know when it happened, here is what happened:-

This power-supply burned out when the computer was not running.

It stank the place out with a smell like that of a transformer overheating.

It has been plugged in with power to it, but with the computer not booted up/running for long periods every day and the computer has had very little use (possibly an hour every six months), but still burned out whilst the computer was not running.

In other words it was not being overloaded, as it was doing no work, so the power wattage rating would/should not be an issue, and it has had very little use.

Perhaps the computer has to be booted up and running for the fan to operate and it somehow overheated whilst doing no work.

Hope this helps.

[Per Hansson]

Re: 470 µf 200 V JEE

Then the "thing" that controls the +5VSB was overloaded...

It can either be a really small transformer or a really simple circuit with some diodes and stuff...

Can't give much more help than that I'm afraid

[gonzo0815]

Re: 470 µf 200 V JEE

Well, as long as the power cord is plugged in, the5v SB and the input caps are on live. Thus either the 5v SB unit, wich is usually build around a topswitch with very crappy capacitors, even in branded psu`s are burnt or the i/p caps are shorted.
I think this psu is death, IMHO not worth any reparing efforth. In any way, i would replace all secondary caps, i/p caps, overvoltage surpressors and probably any semiconductor.

[cybe]

Re: 470 µf 200 V JEE

Sounds like it's beyond economic repair, atleast for my friend.


Thank you everyone for your help, this seems to be a great forum.


The Way home or face The Fire