Antec 350 Recap Epic Fail

[Pentium4]

Re: Antec 350 Recap Epic Fail

I don't think it's even worth trying, this thing looks to be in bad shape...It looks a lot darker in person (my phone doesn't take the best pictures) But on the soldering side it looks like a bunch of joints went cold.

[c_hegge]

Re: Antec 350 Recap Epic Fail

It won't

[lti]

Re: Antec 350 Recap Epic Fail

Why would increasing the voltage rating of a cap hurt anything?

[goodpsusearch]

Re: Antec 350 Recap Epic Fail

You can try

[Pentium4]

Re: Antec 350 Recap Epic Fail

Elite are crap.

Increasing the input caps voltage doesn't hurt. It could help their endurance.

Thanks for the reply yeah I know they're crap, but wouldn't you trust higher rated Elite over Fuhjyyu?

[goodpsusearch]

Re: Antec 350 Recap Epic Fail

Elite are crap.

Increasing the input caps voltage doesn't hurt. It could help their endurance.

[Pentium4]

Re: Antec 350 Recap Epic Fail

I'm recapping a similar SmartPower and want to replace the Fuhjyyu input caps, which I'm not as knowledgeable on. I have some Elite caps (which I consider better than Fuhjyyu) that are 820uf 220V. I forgot if increasing the voltage on input caps causes issues or improves it.

[Behemot]

Re: Antec 350 Recap Epic Fail

I also worked as conductor once, between two heatsinks of one Enhance made Chieftec. BOTH, primary AND secondary are live, so fortunatelly there has been just like 160 V between them. Strange is, SP and my Chieftec are made by different manufacturers (CWT vs. Enhance) and yet they both use the same stupid topology?

As for grounding, on every other PSU I have seen so far I am almost sure the heatsinks were grounded. If rubber pads break, it shorts the PSU and it does not power on. Not that I have ever seen damaged pads between package and heatsink…

[goodpsusearch]

Re: Antec 350 Recap Epic Fail

Isn't the switch mandated to cut both Live and Neutral?
Here in Sweden and the majority of Europe the Schuko plug is used which is not polarized, meaning our AC plugs go in both ways, so we can flip the live and neutral in any equipment.

Same here. The problem is that the switch most psus have only cuts 1 of the 2 lines.

[Per Hansson]

Re: Antec 350 Recap Epic Fail

Because the switch is off, that does NOT mean there is no voltage in the circuits. It likely was a N-GND short, or possibly they messed up big time and put the switch on the neutral, so the components are always live (on hot wire)

Imagine your finger conducting the primary heatsink and the case... Yeah that happened to me... It was an Antec Smartpower 450 and the switch was at the off position but it was connected to neutral..

Isn't the switch mandated to cut both Live and Neutral?
Here in Sweden and the majority of Europe the Schuko plug is used which is not polarized, meaning our AC plugs go in both ways, so we can flip the live and neutral in any equipment.

[bigbeark]

Re: Antec 350 Recap Epic Fail

I did the exact same thing with an original version 300W or 350W Antec SmartPower, which also used high voltage MOSFETs, but after I unplugged the AC and plugged it back in (after installing the case top), the PSU worked normally. Neither fuse blew (this design had 2).

I haven't had too many MOSFETs fail on me, but every one that did had a short between the gate pin and the other pins, regardless of which direction the meter leads were connected.

I've read that the heatsink is connected to 170VDC in order to provide shielding from RF and to make it safer than connecting it directly to ground because sometimes there's no earth ground. The only grounded heatsinks I've seen were in the low voltage section of the PSU, namely in FSP (Fortron-Source Power) brand products.

Thanks for this reply, I think I can safely assume that the primary heatsinks on this PSU are "live" when the PSU is plugged in, courtesy of the bridge rectifier, which allows current to flow between legs of the rectifier. Since the negative leg of the rectifier is connected to the same line as the heatsink ( visible on the back of the PCB), current will flow to the heatsink whenever the PSU is plugged in.

Or, to simplify, never plug the PSU in with the top off!

[larrymoencurly]

Re: Antec 350 Recap Epic Fail

I did the exact same thing with an original version 300W or 350W Antec SmartPower, which also used high voltage MOSFETs, but after I unplugged the AC and plugged it back in (after installing the case top), the PSU worked normally. Neither fuse blew (this design had 2).

I haven't had too many MOSFETs fail on me, but every one that did had a short between the gate pin and the other pins, regardless of which direction the meter leads were connected.

I've read that the heatsink is connected to 170VDC in order to provide shielding from RF and to make it safer than connecting it directly to ground because sometimes there's no earth ground. The only grounded heatsinks I've seen were in the low voltage section of the PSU, namely in FSP (Fortron-Source Power) brand products.

[sam_sam_sam]

Re: Antec 350 Recap Epic Fail

Thanks for pointing this out. If someone plugs in a bad power cable and the heatsink is grounded to the PSU case, the whole computer is "live".
Yikes! So whoever takes the lid off a PSU should be **very** careful about plugging it in, or better, avoid doing so.

I agree with this

[sam_sam_sam]

Re: Antec 350 Recap Epic Fail

I had securely reassembled the PSU, but the top was off, and as I attemped to push the power cord in (switch was off) there was a loud pop and some sparks. The primary side heatsink was apparently live and touched the case.
:

I am glad that you shared this I was working on a Dell Switching power supply and thought about not putting the top on it because of a fan problem

After thinking about this for a few minutes I though this might not be a good idea because it might go

I have another Dell Computer that I will be recapping all of the cap in the power supply and mother board

[bigbeark]

Re: Antec 350 Recap Epic Fail

So, you will need a new fuse, and possibly a new NTC (the green thing - check if it is open circuit)

Thanks Ben7! The NTC is good! I have learned a valuable lesson about working "under the hood":

Never plug the PSU in with the lid off!

[bigbeark]

Re: Antec 350 Recap Epic Fail

To prevent a shock if:

1. The ground is missing
2. The silicone pads break down

They figure that they'd prefer live heatsinks to a ground-fault.

Thanks for pointing this out. If someone plugs in a bad power cable and the heatsink is grounded to the PSU case, the whole computer is "live".
Yikes! So whoever takes the lid off a PSU should be **very** careful about plugging it in, or better, avoid doing so.

[ben7]

Re: Antec 350 Recap Epic Fail

So, you will need a new fuse, and possibly a new NTC (the green thing - check if it is open circuit)

[bigbeark]

Re: Antec 350 Recap Epic Fail

Probably, but desolder to verify just in case something else in circuit is affecting the readings.

So I removed the bridge rectifier and if the positive probe of the ohmmeter is conected to the positive leg of the rectifier and the negative to each leg in succession, there is continuity. if the negative probe is connected to the positive leg of the rectifier and the positive to each leg of the rectifier in succession there is no continuity. So the brdge rectifier only allows currrent to flow in one direction.

I checked another working PSU and connecting the negative probe to the heatsink and the positive to each leg of the rectifier shows continuity on every leg between the rectifier and the heatsink.

I must assume that I blew the fuse when the heatsink contacted the case, and that the heatsink is supposed to be live!

[Shocker]

Re: Antec 350 Recap Epic Fail

If the heatsink can "go live" why is the heatsink not directly grounded to he case, which of course is grounded to the power cord?

To prevent a shock if:

1. The ground is missing
2. The silicone pads break down

They figure that they'd prefer live heatsinks to a ground-fault.

[retiredcaps]

Re: Antec 350 Recap Epic Fail

This time every leg showed almost no resistance between the leg and the heatsink anchor point. Can I conclude that bridge rectifier KBU8J is internally shorted?

Probably, but desolder to verify just in case something else in circuit is affecting the readings.