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momaka
momaka
master hoarder
Last Activity: 02-15-2024, 06:31 PM
Joined: 05-04-2008
Location: VA (NoVA)
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  • Glad you liked it.
    Well, the post looked a little better in its original form, which the new forum software seems to have buggered up a little (especially the smileys and the pictures)... but the information is still there, I suppose.


    For those Nichicon VR "470uF" 350V caps you linked, you have the wrong parts - these are 470[B]n[/B]F (nanoFarads) capacitors at 350V instead of 470 [B]u[/B]F (microFarads). That's smaller by a factor of 1000x. Otherwise 470 uF caps at 350V would be huge - bigger than the 330 uF 200V caps you have on the primary side. So those...
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  • Fixed that for you.

    So essentially it is the same exact PCB model and revision as the Casing Power PSU I liked to above. Thus you can use it to see what I did there when I recapped and modded mine.


    The filter cap spot for the 3.3V rail is 12.5 mm, so that gives you plenty of options to install a bigger capacitor. I put a United Chemicon LXV 6.3V 3900 uF cap in mine.
    For the 5V rail, you can do 2x or 3x 2200 uF caps in 10 mm diameter. Yes, that's quite an increase in the capacitance, but the PSU will be fine. Just DON'T put very low ESR caps like Panasonic...
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    Last edited by momaka; 12-13-2023, 08:37 PM.

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  • The Pentium II CPUs would use around 30-40W max each... so you're looking at 80W there for the pair. And the VooDoo cards... I don't think much of the cards from that era really went past 10-15W. If they have passive coolers, put them at 10W each or maybe 15W just to be on the safe side. Then add 10W for the chipsets and another 10 for inefficiencies and other gremlins inside the machine. With an HDD or two, add another 20W... So the grand total would likely peak at no more than 140 Watts. Maybe 150W if you really want to be on the safe side (though I personally doubt you would see that high of...
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    Last edited by momaka; 12-09-2023, 07:33 PM.

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  • That still shouldn't cause the PSU to blow its fuse. Just about any competent ATX PSU will have short-circuit protection, and I'm pretty sure this one does too, as I'm actually familiar with these Macron Power PSUs.

    But I suppose if the PSU has been tampered with before by another "technician", then anything is possible at this point.


    Ah, you have a Macron Power unit, and the pictures confirm it (I'm rather fond of these PSUs.)

    Actually, when you mentioned those CS-logo caps, I immediately though in the back of my head that this could be...
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    Last edited by momaka; 12-07-2023, 09:26 PM.

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  • If the fuse really was blown, I'd really like to know why. Only way I've seen fuses blow in PSUs is if something is wrong or if someone shorted the primary heatsink to the case by accident. Otherwise, no. Only other exception I can think of is PSUs with APFC circuits, in which case sometimes the fuse can blow when the primary cap is bad or going bad (low capacity) but might not necessarily blow the fuse again the next time... at least until it sees some heavier load.


    Oh yes, they would be.
    Slightly bulged = BAD already (means electrolyte has started to break down and...
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    Last edited by momaka; 12-07-2023, 12:41 AM.

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  • Re: Dell Ultrascan P991 no image.

    Can't 100% tell, but it looks like either the flyback is arcing to something or the HV anode wire is arcing to something.
    If it's the former, the only way to fix this would be a new flyback.
    If it's the latter, you can try to insulate where the wire arcs... though that may not be easy.

    Can you still provide some pictures of the CRT monitor back area? I just want to see (if possible) where the spark gaps are relative to the flyback so I can have a better idea of where the arcing might be coming from.

    And yeah,...
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  • Re: Microwave reacts badly to fat

    Fat and salt water absorb the most energy from the microwaves. Therefore, the magnetron gets loaded the most with these.
    If your display is dimming when such items are in the microwave, it could be because there is either a bad internal wire contact somewhere in the microwave (door switches, transformer, thermal cutoff device, and etc.) or a bad external contact (i.e. bad plugs in your house, or at least the one for the microwave.)

    First inspect the plug and socket where the microwave is plugged in. If it unplugs with barely any...
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  • Re: Power supply filter capacitor measurement in circuit


    Could you double-check your measurements? 350 Ohms or 350 KOhms?

    I don't think that cap could fail with 350 Ohms (DC) resistance and not bulge / heat up like crazy when the PSU is plugged it. At 340V DC (230-240V AC rectified), that would essentially imply the cap to be drawing 1 Amp of current... which at 340V is 340 Watts!!! Either the cap would immediately overheat and vent or it would short-circuit and blow the fuse.

    Since you don't have an ESR meter, here's a better test:...
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  • Re: Need some recommendations for windows cloning.


    +1 for Macrium Reflect

    I've used it on many of my own and more modern personal machines - typically after test-installing Windows 7 or 10 on a regular HDD and then later upgrading said machine to an SSD. Also used it to upgrade the laptops of a few relatives and family friends.

    Just make sure to get the latest version. Some of the older versions have/had weird occasional bugs. But overall, I find Macrium better than AOEMI... though AOEMI is not bad either (used it once or twice in a pinch.)...
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  • Re: LG UBK90 4K Blu-Ray no power


    OK, sorry for the delay. I had to track back a little to see what's going on... and maybe a good thing. Since D102 seems to still test consistently at 50-something Ohms even with the second multimeter, I'll just say to change it. Doesn't have to be an exact replacement diode. Probably any diode will do, even something like a general purpose 1N4148. To avoid having to purchase parts, you can look for one on another scrap PCB or electronic device if you have any. Or maybe borrow the same diode from the working PSU?

    If not, we could...
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  • Re: Dell Ultrascan P991 no image.

    Sounds like either the PSU is having a hard time coming up due to something shorted or tube gone to air. Judging by the sound, I don't think it's the flyback, as it sounds like the HV is trying to come up.

    So open the monitor and take a video of the back area where the neck board goes onto the CRT tube. If there is a cover on the neck board, remove it so it is visible. Then try powering the CRT monitor On. Do you see any of the spark gaps (little glass tubes) on the neck board or the D board sparking inside? If you post a picture with...
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  • Re: Original XBOX Cap ripple current range


    No issues, looks good.

    Though if there is enough height above the 1500 uF and 1800 uF caps, just go with Rubycon ZLH 6.3V 2200 uF for all of these to save with bulk-buying in 10's. Which leads me to your next question:


    Absolutely!
    The capacitance rating on most caps is +/-20%. So most circuits are able to tolerate AT LEAST that much change in capacitance... and in practice, even more (even 2x or 1/2 x capacitance is not overly excessive.) I rarely even bother anymore to try to match values...
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    Last edited by momaka; 11-13-2023, 08:50 PM.

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  • Re: Elite capacitors?

    I'd rate Elite so-so.

    Obviously, they are not 1st tier caps like the "big 5" Japanese brands (Rubycon, Panasonic, UCC, Nichicon, and Sanyo). But they usually do OK in OEM power supplies. Of course, like all of the other 2nd tier caps (i.e. Teapo, OST, Ltec, and etc.), they don't seem to do to well in applications where they see more heat (like LCD monitor power supplies and inverters.) But all in all, I don't mind them too much.

    The 450V ones you show a picture of are probably the primary bulk caps. Being rated for 450V suggests...
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  • Re: HDD stops after about 2 minutes


    Ah, you have a -DM003 series drive - a.k.a. [b]D[/b]oo[b]M[/b]ed drive. These are known to be unreliable.

    Before you chuck it or turn it into something more useful [url=https://www.badcaps.net/forum/showpost.php?p=999322&postcount=53]like this[/url], see if Seagate has a firmware update for it. IIRC, for some of these, Seagate released firmware updates that fixed some of the issues... though bad sectors is probably related to the magnetic coating deteriorating.


    My worst one (ironically also a Seagate)...
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  • Re: Original XBOX Cap ripple current range

    I've used Rubycon ZLH and a few other ZL-based series, along with Panasonic FR, FM, & FS, Nichicon HV and HW, and UCC KZH/KZM to replace UCC KZG and similar equivalents (i.e. Nichicon HM/HN and Rubycon MCZ/MFZ.) ZLH, FR, FM, FS, HV, and HW are not quite up on par with HM, HN, MCZ/MFZ, KZG, and KZJ... but they are close enough and should work fine.

    So if looking for modern replacements that are still made, the above should work acceptably well. If the board you're working on has free/unpopulated cap spots, fill those too...
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  • Re: Liteon pa-3271-06mx help!!!!

    If you get no AC, check or re-solder the input connector. Not uncommon to get cracked joints on those and then get nothing to the PCB. If that's not it, check the solder joints of any common-mode chokes on the input. If these two check out, measure voltage on the primary 400V electrolytic cap. Should get close to 340V [b]DC[/b] with 230-240V AC input going to the adapter.Re: Liteon pa-3271-06mx help!!!!

    If you get no AC, check or re-solder the input connector. Not uncommon to get cracked joints on those and then get nothing to the
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  • Re: Atx psu 5Vstb present, no output

    It's not going to be the est7502 IC - those and many of the TL494 / KA7500 clones are pretty robust ICs.

    The auxiliary winding on the secondary side (from the 5VSB transformer) at 13.x Volts is OK.

    With no images and no further testing, I'd suspect these items first:
    1) Bad cap or multiple bad capacitors on the output (low capacitance / high ESR.)
    2) Bad solder joint on any of the output inductors
    3) Blown BJTs on the primary - a lot of times, one or both can blow open-circuit, along with their Base-drive...
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    Last edited by momaka; 11-10-2023, 10:28 PM.

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  • Re: MSI K7T266 Pro (Ver. 1.0)

    The Chemicon KZE caps can stay - these are pretty good stable series.
    The Sanyo OSCON caps are polymers and likely will never have any issues for the lifetime of the board's use.
    Tayeh and Chhsi need to go for sure.

    By the looks of it from the pictures of this board, two of the KZE filter the 5V rail for the CPU VRM, while the other three KZE and the Sanyo OSCON filter the CPU V_core. Everything else appears to use linear regulators on the board, so no need to care too much about ESR.

    The Chemicon KY caps...
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    Last edited by momaka; 11-10-2023, 04:35 PM.

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  • Re: Monster Power HTS 5100 MKII Power Center

    For starters, I see lots of the infamous tan/brown glue that goes conductive over time, under the big transformer and the aluminum heatsink on the board. So first order of business would be to remove that glue - all of it. Chisel away with a flat screw driver, but be careful not to damage traces or nearby components.

    Next, check diodes D15, D16, D27, and D28 - they look a little faded / overheated and might be shorted. R27 looks like it has seen a little more power than it should and should be checked as well for abnormally...
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  • Re: DIY PCIe x1 video card...


    Only if it's a PCI model. Then it works great in those old (retro?) 32b P4 Dell desktops that don't have AGP slots.

    Compared to the onboard i865, this is a significant boost in graphics "power".


    Sounds about right, at least on the desktop side.


    Purely going by the TDP (20W) divided by the die surface area (79 mm^2), I think it has a decent chance of lasting... provided the cooler is able to keep it cool. No matter what ATI/AMD and nVidia say, any temperature over...
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