PeteS in CA
Badcaps Legend
Last Activity: Yesterday, 05:06 PM
Joined: 08-10-2005
Location: San Jose, CA
-
Is 5VSB OK? DC voltage and ripple? -
How comparable are the turn-on, and turn-off times and the input capacitance? Those may also be critical parameters.Leave a comment:
-
Supermicro's main board model numbers reflect the generations of Intel's processors. e.g. X6 was followed by X7 which was followed by X8 and so on. "20 years old" sounds about right for an X6 main board, making it approximately contemporary with Win XP, which MS stopped supporting and updating long, long ago.
X10 generation main boards were in their prime around 2016. While that's "just" 8 years ago, X13 and X14 generation main boards are most of current sales. BIOS updates to X10 main boards have probably been limited for a couple of years to just fixing security...Leave a comment:
-
It might do 200W continuous without launching. Efficiency will probably be in the 70% range, maybe 75%. If those output inductor cores get hot they will degrade pretty fast.Leave a comment:
-
Don't know if this helps, but here is TI's paper on the TL494, [url]https://www.ti.com/lit/an/slva001e/slva001e.pdf[/url] .https://Don't know if this helps, bu...1e.pdf[/url] .Don't know if this helps, but here is TI's paper on the TL494, [url]https://www.ti.com/lit/an/slva001e/slva001e.pdf[/url] .Leave a comment:
-
Having seen PWAs with several layers burned through due to a tantalum cap that had an incendiary event, I would replace it and every other damaged tantalum cap on that PWA. If that PWA was built in mid 20011, I'm surprised tantalum capacitors were used. Sun Microsystems started eliminating tantalum capacitors from its products in the mid 1990s (when a $0.50 or $1.00 cap burns and emits smoking, shutting down a large data center, it gets customers POed. I just looked over several modern server MBs and saw zero tantalum and lots of polymer capacitors.Last edited by PeteS in CA; 09-09-2024, 11:30 AM.Leave a comment:
-
While replacing the bad output caps was necessary, your problem is in the 5VSB circuit. Without 5VSB, shorting PS_ON to Return will do nothing. stj's comment is worth exploring. If there is a 47uF or 100uF (or similar low value) capacitor in the 5VSB circuit, that may be the problem cause. Those can go bad without looking bad visually. Also look to see if the standby regulator is getting voltage. No input voltage means no output voltage. If there is a high ohmic value resistor between the high voltage and the standby regulator, it may be open-circuit....Leave a comment:
-
From a 1980ish context and perspective, in the US, Rifa PME271 series were what was available. Wima, Siemens, and other European manufacturers came into the US a few years later. Some folks here regard 40 year-old parts failing dramatically as defective. To me, failing after years of surges and being 40 years old is just a realistic, if bad-smelling and inconvenient, outcome.
To your failed power supply, just replace all Rifa PME271 caps in it (even ones that have not yet failed) with polypropylene or polyester X and Y caps. If it's a switching power supply (original TRS80 power supplies...Leave a comment:
-
As [B][URL="https://www.badcaps.net/member/47641-dmill89"]dmill89[/URL][/B] pointed out above, that is not a Delta Electronics//Delta Products power supply. Delta would not use wimpy heatsinks like that for a 500W power supply, and probably not even for a 250W unit. Delta doesn't install jumper wires where common mode inductors belong. Delta would NEVER use 1KV DC or 2KV DC ceramic caps instead of agency-approved Y-caps! Never!!! That output filter section is pretty pathetic. The input rectifiers are pretty small, and the output transformer core would not be good for much over 250W....Leave a comment:
-
IIRC, Nichicon's HD series is equivalent to KY series, and the HE series is equivalent to the KZE series, in terms of impedance. However it looks like some parts in the two series have been discontinued. Nichicon's PA series is very close in impedance to the HE series, though I do not know how readily available that series is (not discontinued, just not as popular).Leave a comment:
-
Probably __CV-NB21088. I can't make out the first two characters. I don't know how much help knowing the part number is, since the transformer is probably Delta custom/proprietary and probably not available outside of Delta. Transformers tend to be pretty reliable. Why do you think this one is bad?Leave a comment:
-
Someone else will have to interpret the code, but that may be a TVS diode or rectifier.Leave a comment:
-
I can't make out the brand of the two large caps, which probably should be replaced, since one is bulged. The small ones are Illinois Capacitor, which is a fairly good brand. Replace or leave alone depends on lots of factors. Age is one. At 30YO or greater, I'd consider it. The ambient temp when in use is a factor (e.g. 85C caps in a 70C internal ambient are probably not going to last as long as if the internal ambient is 50C). The application matters. Use as a switching P/S output cap is more stressful than use as a decoupling capacitor in an analog or digital circuit. Not being powered on for...Leave a comment:
-
Replacing electrolytics with high value MLCCs is probably not a great idea. They have very different impedance vs. frequency characteristics, and high value MLCCs usually (almost always?) have tempcos such as Z5U or Y5V, in which the capacitance at operating temperatures could be 20%-40% or the nominal value.Leave a comment:
-
The Fluke 87 DMM I use is powered by a 9V battery, but the voltage for testing resistance is limited to 2V or so. As for testing capacitance, what a DMM can test is best learned from the DMM's specifications. I haven't used my Fluke 87 to test capacitance. AFAIK, an ordinary DMM doesn't test ESR or impedance.Leave a comment:
-
So, picking out a few bits and pieces:
It looks like the TDK transformer has an 8823 date code, i.e. 23rd week of 1988.
The switch device may be a clone of the MJ12006, an 8A, 450V NPN transistor, designed for switching power supply use.
I don't see an output inductor, so I think the topology is discontinuous flyback.
Putting these latter two together I'd guess the power rating would have been 100-150 watts. Given that its some 35 years old, it is possible that the electrolytic capacitors have dried out and/or the aluminum oxide dielectric has thinned, making...Leave a comment:
-
Be sure to match the temperature coefficient if you know it. If you don't, use X7R or CGO.Leave a comment:
-
Maybe the frequency was too high and a TWT should have been used....Leave a comment:
-
Electrolytic capacitors, typically, are +/-20%, so on the low end the cap can be as low 544uF.Leave a comment:
No activity results to display
Leave a comment: