Antec Power Supply

[trwilson70]

Newbie here. Have repaired various LCD's recently - never a power supply. Picked up a used Antec Aria case - but has a bad AR300 power supply. Upon inspection I noticed a bulging cap - and the component next to it unsoldered, obviously it got hot. Did the bad cap cause this or vice versa? What is the other component? The other caps look fine - from what I can see - they are all teapos. This is an odd shaped PSU or would just replace. Thanks!

[mockingbird]

Re: Antec Power Supply

Is that a picofuse?

[Toasty]

Re: Antec Power Supply

No, it's a zener diode. Marking on the board is ZD4.

There are other threads in here about these PSU's:
https://www.badcaps.net/forum/showthread.php?t=6646
https://www.badcaps.net/forum/showthread.php?t=7169

These are limited to Antec for supply due to the oddball casing. These people still show stock (51) even though it's the AR350 model (check the case size):
http://www.provantage.com/antec-ar350~7ANT900Q.htm

I'd replace the cap and put the diode back in place and test the unit. If it comes on and voltages are (near) correct, recap the entire unit. If not, get the new one and recap it.

Toast

[trwilson70]

Re: Antec Power Supply

Thanks Toast - have a cap coming. I had read one of the threads, not the other. If it works will recap - hate to buy new.
TR

[Khron]

Re: Antec Power Supply

An overall photo of the board from the top and bottom might help trace the real cause of that zener getting cooked. I have a thread in this forum where, among other things, i had a burnt zener close to the 5VSB transformer, in an Antec SP500P.

[trwilson70]

Re: Antec Power Supply

Thanks all for the replies. Received the cap and got a chance to install this morning. After installation plugged it in - with a load - got a familiar high pitch whine - which is better than before. Have heard this before on other PS's - what is the cause - I always figured it was the big cap. Got photos of both sides of the board prior to installing the cap and diode. Thanks

[seanc]

Re: Antec Power Supply

Did you replace the toasted zener diode yet? I'd be interested to see if it makes any impact on reducing the whine.

I have a re-capped Jeantech PSU with a failed zener that whines, another working one of the same model does not whine.

[Marstee]

Re: Antec Power Supply

You need to replace the zener diode ZD4 1N4746A 18v 1.3W. Replace EC4, 100uf 50v, EC3, 22uf 50v and on the print side of the board R29 may be burnt, it is a 6.5R SM resistor connected to the primary side of the 5VSB transformer. Make sure when you replace the 18v zener you leave about 2mm clearance to the board surface and meter the diode after replacement. You should get 400 to 700mv fwd on a diode tester. If you get similar both ways the board is carbonised and is conducting! Push the diode down towards the board very gently to break the bond between the copper print and the board on the side that is most burnt and refix with a small gap using super glue. I know this sounds very "heath robinson" but it works. When the glue is dry, re meter the diode and it should be fine. Check all the secondary caps for bad ESR or bulges and replace. Then test the PSU, all should be good.
Good Luck, Steve

[PCBONEZ]

Re: Antec Power Supply

Is that a TFX form factor?
If so Enhance made some good ones with all Jap caps.
.

[Marstee]

Re: Antec Power Supply

Correction! The surface mount resistor R29 value is 5.6R, my apologies for the typo.
Steve