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Old 09-04-2015, 05:58 PM   #1
everell
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Default Alllied AL-C350ATX

My latest project, a L&C Allied AL-C350ATX, completely dead. No 5VSB, and a two transistor 5vsb circuit. Also a couple of bulging Saturn capacitors in the output. So I have started by removing the pc board from the case. Here are some pictures.
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File Type: jpg Al 7.JPG (708.4 KB, 19 views)
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Old 09-04-2015, 06:54 PM   #2
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Default Re: Alllied AL-C350ATX

I would try to repair that. Looks capable of 350W.
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Old 09-04-2015, 07:20 PM   #3
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Default Re: Alllied AL-C350ATX

The 'saturn' caps on that PSU are Yang Chun. It definitely seems to have a bit of beef to it. It looks similar to this - http://www.hardwareinsights.com/wp/t...TM-420-PSAR-I3. I pulled 350W from it, but blew it up at 400W. I wouldn't trust it for any higher than 300W for a long period of time, though.
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Old 09-05-2015, 02:41 AM   #4
everell
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Default Re: Alllied AL-C350ATX

I replaced the output pi filter capacitors on the 12 volt, 5 volt, and 3.3 volt rails with Nichicon PW series capacitors. Two were bulging and had high esr. The remaining four measured ok for esr. I decided to replace them all since I don't trust Saturn capacitors.

The two mains capacitors are also Saturn. I am wondering if I should trust them or change them. So what do you think?
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Old 09-05-2015, 04:07 AM   #5
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Default Re: Alllied AL-C350ATX

Measure their capacitance and if it is in specs leave them alone.
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Old 09-09-2015, 11:31 AM   #6
everell
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Default Re: Alllied AL-C350ATX

With power applied, no 5vsb. With the pc board out of the case I can now troubleshoot it. First, the fuse was blown. No wonder it has no 5vsb! I started checking silicon devices. Switching transistors OK, output diodes OK, then found that one of the diodes in the input bridge diode was shorted. Replaced bridge diode and fuse. Now it is up and running. I wonder what blew one of the diodes in the bridge diode??
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Old 09-09-2015, 12:40 PM   #7
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Default Re: Alllied AL-C350ATX

errr bad caps? couldnt have been anything else...
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