PeteS in CA
Badcaps Legend
Last Activity: Yesterday, 04:28 PM
Joined: 08-10-2005
Location: San Jose, CA
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Curtis Instruments motor controllers are designed in their division in Livermore, California. [url]https://www.curtisinstruments.com/products/motor-controllers[/url]https://Curtis Instruments motor con...trollers[/url] -
It looks like it might be a discontinuous flyback design. If my guess is correct, VR1 (TO-92 package), located a bit above T2 in your picture, might be a TL-431. While this is nominally a programmable reference IC, it can also be used as a comparator with a reference on one input, and through an opto-isolator or transformer (T2?) to turn of the switch device. Thus a TL-431 (or TL-430) can be the controller.
I don't have a schematic, but if the switch is not turned off, it might remain on long enough for the main transformer core to saturate, blowing the IRF840 and input fuse.Leave a comment:
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This may seem odd, but since the P/S is probably more than 20 years old, there is the possibility that:
* Output caps you replaced now have capacitors that are "too good", their impedance is too low, causing instability;
* Output caps you did not replace are high impedance, causing instability.Leave a comment:
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I've had very good experience with Nichicon HE, Chemicon KZE, Panasonic FM, and Rubycon ZL series, but those might be "too good" (too low impedance, possibly causing stability problems) in older VCRs.Leave a comment:
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Given polymer caps' low impedance and where those 'lytics were in the output filter circuit, the 'lytics really should not have been terribly stressed. Those Asia'X caps were pretty awful, and a decent P/S mfr should have known to use decent 'lytics for output filtering.Leave a comment:
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These are fairly mature and have similar characteristics:
Nichicon PW series
United (Nippon) Chemicon LXZ series
Panasonic FC seriesLeave a comment:
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This picture is of ceramic capacitors with quite a few safety agency logos:
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"Ceramic-Capacitor-DCF-Y1-X1-Capacitor-Y-Capacitor-Capacitor-Y-.jpg","data-attachmentid":3590389}[/ATTACH]...Leave a comment:
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If those blue ceramic caps near the top tight of your picture are DC-rated instead of safety agency-approved and rated for an AC voltage, remove them, and if you can replace them with proper Y-caps.
While the heatsinks look possibly OK for 250W-300W, the 330uF input 'lytics and output inductor probably limit the realistic output power to 150W-200W. 470uF or 560uF input 'lytics would be needed for input filtering adequate for 250W or 300W, but that output inductor would have to have a larger core and probably heavier gauge wire, and the output caps might not be adequate for those power...Leave a comment:
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The PM series is Nichicon's RoHS-compliant version of the PL series. It was introduced, AFAIK, in the early 2000s. I first saw them in 2005, and in the several prior years I had been at a company making military power systems, so how long before 2005 the series had been around, I'm not sure. FWIW, Nichicon's PS series (if it's still around) is the RoHS-compliant version of the PR series.Leave a comment:
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On the plus side, users would not have to worry about Y-caps that are not safety agency approved....Leave a comment:
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Given the age, if it is an electrolytic I'd suggest Nichicon PS, PM, PJ, or PW series, in that order of preference, whatever fits. I'm not sure whether polymer caps were coming into use in 1996.Leave a comment:
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Is 5VSB OK? DC voltage and ripple?Leave a comment:
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How comparable are the turn-on, and turn-off times and the input capacitance? Those may also be critical parameters.Leave a comment:
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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:
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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:
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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:
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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:
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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:
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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:
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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:
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