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C2 fireworks show!
Posted:
Tue Aug 03, 2004 7:12 pmby baby
I just plugged in my PS02 for the first time and got smoke and sparks from the tant at C2...what else should I look for before I replace it and it happens again. Its orientation was correct BTW. Thanks for your help!
-Mark
Posted:
Wed Aug 04, 2004 7:21 amby Bastiaan
Did you wire J5 correctly? If you are in a 220V country and you havent changed that to pin 2+3 shorted you are feeding the powersupply 200% of its needed voltage....
C2
Posted:
Wed Aug 04, 2004 8:19 amby tpryan
More likely you've got a problem around U3. Make sure you haven't got any shorts directly from input to output. Power it up without C2 installed and measure the +48V output. If it's anything higher than 48.5V, you have a problem around U3. If the voltage is OK, just try another cap. It's entirely possible you had a bad one.
Posted:
Wed Aug 04, 2004 8:23 amby baby
Yeah...I'm a 110 guy...and it's wired right, according to the assembly photos. I cannot seem to find my schemo and the pdf on the website leads nowhere.
I hope I didn't totally fry something. This is education.
-Mark
Posted:
Wed Aug 04, 2004 8:49 amby baby
Tim-
I removed C2 and this time I decided to power it up slowly with a variac. At about 80v either R5 or U2 started to smoke. I had no time for a measurement!
17.66 ohms across IEC +/-...0 ohms to ground...
PS02
Posted:
Wed Aug 04, 2004 10:24 amby tpryan
It sounds like you have bigger issues than a bad cap. Make sure you've got the insulating pads and nylong washers installed on the regulators correctly. You must not have any shorts between the regulator tabs, or between either regulator tab and the heatsink. What resistance do you measure between the regulator tabs? Check that before you apply power again. The PS02 schematic links are now working.
Posted:
Wed Aug 04, 2004 10:54 amby baby
I am up and working now...mostly. The smoke has cleared, literally, thanks to FOLLOWING DIRECTIONS and using washers to mount the regs.
Now I have +33v, -5v, and +48v. I still can't link to the schematic...I may have made that parts list mistake. Thanks. You rule.
-Mark
PS02
Posted:
Wed Aug 04, 2004 12:20 pmby tpryan
Well, that's progress. The wacky output voltages may be due to damaged resistors or regulators. You can get a rough idea of the resistor values if you measure them in-circuit, but you'll have to open one end to get an accurate reading. The schematic links are definitely working, you may have to refresh (in the left pane) to update your browser cache.