EC 350X fried Power Supply (Probably a Codegen)

[goodpsusearch]

That psu was taken off a PC that I got as a gift from a friend 2 weeks ago.

The label layout is similar to Codegen. Same with the model name.

There is a big fan that is dead.

The fuse is blown.

Nearly complete input filter, only MOVs are missing.

Look at the 4 tiny diodes in place of a bridge rectifier...

The primary caps are HEC 470uF but their real capacitance is 321uF.....

Switching transistors: 2x 13007...

The transformer is 33 size..

The heatsinks are tiny and lame.

There is S20C.. for 5V, S20C... for 3.3V and F16C... for 12V..

There are burn marks on the switching transistors and secondary diodes areas.

I found a short on the primary section but I didn't look if it's in the switching transistors, the 4 diodes or somewhere else.

The output toroid inductors look (and smell) burnt too.

Output Caps:
2x470uF @ 5Vsb
2x1000uF @ 3.3V
2x1000uF @ 5V
1x1000uF @12V

All caps are HEC, none is bulging.

The soldering job is not so good.

Funny thing 1: The label says thermal control, but judging from those heatsinks this was not a good idea.

Funny thing 2: Even though the fan wasn't working at full speed, that didn't keep it from dying

Funny thing 3: That psu was powering the following computer:
Pentium 4 3GHZ (Prescott) Hyper Threading
1.5GB DDR 400
Nvidia 7600 GT
120GB IDE 7200 HDD
DVD Rom
DVD Rw
TV Card

[Th3_uN1Qu3]

Re: EC 350X fried Power Supply (Probably a Codegen)

Classic failure mode from overload. Check 12v rectifiers and primary transistors.

[kaboom]

Re: EC 350X fried Power Supply (Probably a Codegen)

Also, do something about the sloppy construction. As in, heat up/resolder/remove&replace components with excess lead length. You don't want things on the primary side anywhere near those of the secondary.

"HEC," the input caps are of dubious quality. No surprise there.

Also check the resistors and the two 4148 diodes for the bases of the two switching transistors. The two 2.2-4.7u caps in the base circuits should be replaced with units of better quality- as should all the caps.

What's with the fuse? Looks like a normal 5x20mm with 'pigtails' soldered on...

[c_hegge]

Re: EC 350X fried Power Supply (Probably a Codegen)

Here's what I would do:

1. replace the secondary rectifiers with parts scavenged from other PSUs. The PSU should now start and the secondaries won't fail again

2. Pour petrol over the PSU

3. Load it to around 300W, stand back and watch the humungus fireball as it blows itself up

OK, don't try it, but it would be fun.

[Th3_uN1Qu3]

Re: EC 350X fried Power Supply (Probably a Codegen)

What's with the fuse? Looks like a normal 5x20mm with 'pigtails' soldered on...

Probably been replaced only to blow up again. At least this one HAS a fuse. One of the PSUs i got once had its fuse jumpered with heavy gauge wire and the voltage selector switch set to 115v. One of the primary caps blew open when i plugged it in - you could imagine the noise it made.

[c_hegge]

Re: EC 350X fried Power Supply (Probably a Codegen)

I'v never actually seen a fuseless PSU before (although I have seen primary caps explode before).

[goodpsusearch]

Re: EC 350X fried Power Supply (Probably a Codegen)

This belongs to the "for parts" pile.. Not worth repairing!

[370forlife]

Re: EC 350X fried Power Supply (Probably a Codegen)

This is indeed a codegen, as the fan is a "tricod science" which is a member of the codegen group.

[goodpsusearch]

Re: EC 350X fried Power Supply (Probably a Codegen)

This is indeed a codegen, as the fan is a "tricod science" which is a member of the codegen group.

And it failed! They can't do right even a fan...

[lti]

Re: EC 350X fried Power Supply (Probably a Codegen)

It is probably a sleeve bearing fan. Nobody can make a sleeve bearing fan last very long.

[c_hegge]

Re: EC 350X fried Power Supply (Probably a Codegen)

Papst can. They use teflon-lined sleeve bearings AFIK.

[momaka]

Re: EC 350X fried Power Supply (Probably a Codegen)

This belongs to the "for parts" pile.. Not worth repairing!

I agree.
When a cheap PSU like this has multiple failures, it's just not worthwhile to fix it when another cheap working PSU can be found easily.

It is probably a sleeve bearing fan. Nobody can make a sleeve bearing fan last very long.

I think part of the problem is that many of the cheap fans don't get proper lubrication (if any at all) from the factory. I've never had cheap sleeve bearing fans seize on me again after disassembling completely, cleaning, and then lubing.
From all of the cheap sleeve bearing fans I've seen, only Power Logic (usually found in Deer/Allied/L&C/Solytech PSUs) has proper lubrication. I had a L&C PSU with one of those - it held fine for 7 years of regular use at full blast (12v). Still had lots of oil when I opened it for cleaning.

[lti]

Re: EC 350X fried Power Supply (Probably a Codegen)

There are many adaptations of the sleeve bearing that have a long lifetime, but a standard sleeve bearing doesn't last very long. However, I found an eight-year-old Adda fan that still had plenty of oil inside it and still ran like new.

I wonder how long a Sunon DR-Maglev fan will last. They are completely sealed with no way to disassemble them. They are quiet and don't vibrate, unlike Sunon's older fans. I have one in a PSU.

What fan controller circuit is used in this PSU? I have heard of cheap PSUs just placing a thermistor in series with the fan.

[goodpsusearch]

Re: EC 350X fried Power Supply (Probably a Codegen)

What fan controller circuit is used in this PSU? I have heard of cheap PSUs just placing a thermistor in series with the fan.

Linkworld does that. The fan works nearly full speed all the time but this is right if you see the heatsinks those psus have.

That power supply also did that and the thermistor was hotter than the heatsink it was mounted on

Codegen have some sort of fan controller that makes them run hot enough to die soon.

[c_hegge]

Re: EC 350X fried Power Supply (Probably a Codegen)

Most of the cheapies (codegens included) I've seen have no fan controller at all.

The inly exception is https://www.badcaps.net/forum/showthread.php?t=12323 (the only good codegen I've seen. I still have it, although I replaced the fan with an Arctic cooling temperature controlled one and wired it straight to 12V. I think it should speed up a bit more as it warms up. I have also recapped it.

[lti]

Re: EC 350X fried Power Supply (Probably a Codegen)

He said it has a fan controller.

Many PSU manufacturers use a fan controller that makes the PSU overheat. Also, I have seen two Hipro PSUs where the thermistor was not touching the heatsink, even though it should have been. One got so hot that the caps near the heatsink failed. The other one made the case feel warm near the PSU, but the fan was so weak that it would have run hot anyway. That is the PSU I put the Sunon fan in. It runs cooler and the new fan is also quieter than the original.