Re: Delta DPS400-MB, pwr_ok stays low
Thanks for chiming in, every bit of advice got me closer to solving the problem.
First I tried the external resistor trick sugested by [b]kaboom[/b], and it seemed to indeed solve the problem. So I opened the PSU again and inspected the small board. Traced the gray wire and it only connected to a single point inside the PSU, that being pin 3 of the '1002' chip.
There are two pair of pads in the area, one for pulling P.G. to +5V, the other for pulling it to GND. None was populated - the PSU came like this from the...
quicknick
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Last Activity: 11-07-2023, 07:18 PM
Joined: 05-16-2009
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Re: Delta DPS400-MB, pwr_ok stays low
Thanks for the hint! I searched around, found some schematics and also [URL="https://www.badcaps.net/forum/showthread.php?t=64867"]this thread[/url] describing a very similar problem.
I'll investigate further in the following days, checking the small caps on the mainboard and the voltages around the chip, maybe replacing the two LM339.
@Topcat - thanks, I guess I'm too old-fashioned (or maybe just old) - I was trying to save this board some bandwidth
Re: Delta DPS400-MB, pwr_ok stays low
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Delta DPS400-MB, pwr_ok stays low
Howdy folks,
I recently got this PSU to replace the 250W Delta unit in my "Retro-PC workhorse" - the rig that I'm using for testing most of my retro stuff.
[url]https://www.badcaps.net/forum/attachment.php?attachmentid=260024&stc=1&d=1648432776[/url]
[url]https://www.badcaps.net/forum/attachment.php?attachmentid=260025&stc=1&d=1648432776[/url]
[url]https://www.badcaps.net/forum/attachment.php?attachmentid=260026&stc=1&d=1648432776[/url]
Cleaned it good (wasn't too dirty to begin with) then... -
Re: Very old Sanyo OS-CONs. Safe to use?
Thank you for all the answers (and for the datasheet, the case size is indeed the same). Haven't had the time to play with them, but I'll check back in a few days with some results.Leave a comment:
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Very old Sanyo OS-CONs. Safe to use?
Hi folks,
Some time ago I got (for very cheap) a bag of 200 Sanyo OS-CON SA series, 220uF/10V, manufactured January 1988. Measured a few of them and the readings were all over the place so I put them in storage.
Fiddled with them one more time today, to decide if I keep or throw them away, and noticed that strange readings are due to a layer of practically invisible oxide that developed on the leads. Rubbing them just a bit with fine sandpaper or even with the tester probes and they can be tested OK, tried with 10 of them and they mostly measure towards 250uF, with one...Last edited by quicknick; 07-24-2020, 04:53 PM. -
Re: A8N-SLI Premium full recap gone bad
I might be wrong, but I wouldn't trust any cap that was reverse-biased for any length of time.Leave a comment:
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Re: Retro polymod: Abit NF7-S 2.0
Thank you for all your suggestions and advices. Job is done, here it is:
After swapping all the capacitor, board seems to have regained some of the original OC capability. Further tests are needed, but not much time to do that ATM. For one, I clearly need to test with a stiffer PSU.
The coils are not 15 turns, rather 5.5 turns or so, with three wires in parallel.
I chose the lower capacitance because that is suggested everywhere as a rule in poly-mod. Now it's the first time I hear this isn't a good practice....Last edited by quicknick; 01-14-2019, 06:16 AM.Leave a comment:
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Re: Retro polymod: Abit NF7-S 2.0
Yes, that's the board. Mine also has SATA, but otherwise it's identical.
The caps that I replaced first were 11 out of 14 or so that were bulged. After this step, the board started working. 10 of them were Nichicon HM 1000uF/10V, replaced them with Rubycon YXG 1000uF/6.3V from a dead Gigabyte board. I'd have replaced the other three but 10 was all I could salvage from the dead board. Coincidentally, my other Abit NF-7 uses the exact same Rubycons instead of the HMs (and none is bulged). The 11th replacement was at the AGP slot, very...Last edited by quicknick; 01-09-2019, 05:18 PM.Leave a comment:
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Retro polymod: Abit NF7-S 2.0
Hi everyone,
Got myself the board in the title, from the local fleamarket. Have really good memories about it (had it back in the day), and as I recently got interested in retro stuff... why not?
Board was in very good shape, except for bulging on 13 (out of 21) Nichicon HM 1000uF/10V, and another bulged 1800uF/6.3V near the AGP VRM. Tried a power-on nevertheless, another one of them (near the BIOS chip) spewed its juices when I applied power. It didn't start at all.
For a quick check, and too see whether I should spend money on a full recap, I took 10 caps... -
Re: Samsung syncmaster 205bw
Same monitor as the one we're discussing in this thread, Samsung 205BW. Same boards as Dixie's - i noticed there are many different layouts, but his boards are identical to mine. I'll post pictures in a few days, no camera at the moment. Same symptoms as those described by Dixie and others in this thread - power led stays solid blue, cannot turn off, backlight stays off.
Power supply is ok after replacing the swollen caps, today I checked the 3.3v and 1.8v regulators on the signal board and their output is ok. The three wires labeled BL_EN, BL_ANALOG...Leave a comment:
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Re: Samsung syncmaster 205bw
Hello - I have the same monitor, same board versions, same problem.
Replaced three bulging caps, nothing happened, blue power led remains lit after power is applied and nothing else works (13V output from the PSU board is ok). Even replaced the two 1000uF/25V caps that were not swollen - same thing. Has anyone successfully repaired a 205BW that shows these symptoms?Leave a comment:
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Re: Nippon Chemi-Con KMH fakes?
Found out the answer to one of the above, C=T/R. I used a 2 Kohm resistance and a 66V supply, it takes about 32 seconds for a cap to reach 42V (63% of supply voltage), that means around 16000uF. Not fakes then?Leave a comment:
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Re: Nippon Chemi-Con KMH fakes?
Well, I cleaned the "bungs" with cotton swabs and isopropyl alcohol and they look normal now (see pic).
Any method to measure capacitance and leakage? (ESR would be hard to measure without an ESR meter I guess). I figure the capacitance could be found out by measuring the time it takes to charge the cap to a certain voltage thorugh a resistor, but what voltage should I use and what's the formula that gives me the C?...Leave a comment:
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Re: Nippon Chemi-Con KMH fakes?
Bad luck seems to follow me when it comes to caps. These Chemi-Cons just arrived to me from the US, and they look (and feel) somewhat different of what I expected. Of the 12 units, most of them have some sort of residue on the rubber pad at the bottom, something resembling wax but a bit harder (can be scraped by fingernail though). It has a faint smell, not like electrolyte but more like something petroleum-based. Any ideas on what this might be?
Second, I think the markings should be of better quality.
Third, all of...Leave a comment:
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Re: Nippon Chemi-Con KMH fakes?
Thanks for that datasheet, I only knew about this one:
But... case size is specified at 40x80 in the datasheet for the 10,000uF/100V, and my caps only measure 35x50. Isn't that a bit strange?Leave a comment:
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Re: Any chance these are genuine?
Fakes, then...
Good thing I haven't bought many of them. Not from ebay, just some local stores...Leave a comment:
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Nippon Chemi-Con KMH fakes?
Last autumn I bought from someone eight 10,000uF/100V capacitors, Nippon Chemi-Con KMH series that should've been brand new... They didn't look like brand new to me when they arrived but also I couldn't find signs they were used... just some scratches, maybe from storage.
Most important, two of them were a bit shorter than the other 6 (45mm vs 50mm). But the price was very good and I asked no questions, just started using them right away as filter caps in my amplifier power supply (four on each channel, two per rail).
A couple of months later, while doing some re-wiring... -
Any chance these are genuine?
I recently got some Panasonic caps, different series and ratings... But none of them have the characteristic T-shaped vent, all vents are X or Y-shaped (photos attached)... Is there any chance of these caps being genuine or I am better by throwing them at the garbage bin? Thanks,
Nick...
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