Forum: Troubleshooting & Designing Networks
Yesterday, 04:29 PM
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Replies: 27
Views: 540
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Forum: Troubleshooting & Designing Networks
08-04-2022, 12:17 PM
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Replies: 27
Views: 540
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Forum: Troubleshooting & Designing Networks
08-04-2022, 01:20 AM
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Replies: 27
Views: 540
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Forum: General Capacitor Questions & Issues
07-30-2022, 12:13 AM
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Replies: 13
Views: 455
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Forum: General Computer & Tech Discussion
07-22-2022, 02:02 PM
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Replies: 4
Views: 234
Re: Psu pc Hp sff
I've worked on two of those HP SFFs, 6300's IIRC. One had a junk "replacepower" replacement, whose original caps failed after 6 months or so.
The second had its original PS, but with tired/bulging...
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Forum: Troubleshooting Power Supplies and Power Supply Design
06-20-2022, 04:17 PM
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Replies: 30
Views: 1,099
Re: Learning with ATX CHIEFTEC 450W PSU
If it hasn't been mentioned already, make sure you're using the correct common point!
If you're shunting that pin of the APFC IC, it will go to the - side of the line rectifier!
Not secondary DC...
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Forum: Troubleshooting Power Supplies and Power Supply Design
06-17-2022, 10:46 PM
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Replies: 30
Views: 1,099
Re: Learning with ATX CHIEFTEC 450W PSU
You're choking the APFC with the bulb in series with the AC line. For initial testing with the standby supply, you can use the dim-bulb, but the APFC will try to boost & charge the main B+ cap when...
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Forum: General Computer & Tech Discussion
04-14-2022, 08:06 AM
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Replies: 21
Views: 1,735
Re: Can a new computer smell like urine?
Actually, I use MAF sensor cleaner on PCBs, if/when I don't want to "waste" my CRC QD.
Are we certain this is a *new* motherboard?
:D
Not that I do it much anymore since the bottom's fallen...
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Forum: Troubleshooting Audio Equipment
04-11-2022, 01:50 PM
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Replies: 2
Views: 510
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Forum: General Capacitor Questions & Issues
04-01-2022, 12:32 PM
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Replies: 10
Views: 1,052
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Forum: Troubleshooting Power Supplies and Power Supply Design
03-30-2022, 02:42 PM
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Replies: 7
Views: 675
Re: Delta DPS400-MB, pwr_ok stays low
Excellent, another one saved/fixed!
:nod:
IIRC, there were some AT-era Compaqs that had the PG circuitry on the MB.
I found this out when building a "retro PC" with a PS from one of these,...
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Forum: Troubleshooting Power Supplies and Power Supply Design
03-28-2022, 04:55 PM
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Replies: 7
Views: 675
Re: Delta DPS400-MB, pwr_ok stays low
There should be a "pullup" resistor from +5 to PGO, as the latter is typically an "open collector" output.
If this is open, PG will never go high, no matter what's going on with the...
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Forum: Troubleshooting Power Supplies and Power Supply Design
03-11-2022, 09:59 PM
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Replies: 8
Views: 753
Re: Laptop power brick audibly noisy
It's one of the cheaper "laptop replacement" power supplies.
Almost the same board as one I scrounged for parts, bigger transformer, same heatsinks- just wider, and the same lack of input...
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Forum: Troubleshooting Audio Equipment
03-10-2022, 09:37 PM
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Replies: 23
Views: 1,952
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Forum: Troubleshooting Audio Equipment
03-05-2022, 08:14 PM
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Replies: 5
Views: 553
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Forum: Troubleshooting Power Supplies and Power Supply Design
03-03-2022, 10:53 PM
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Replies: 12
Views: 624
Re: 9v super basic wall wart issue
Soldering heat from R&R'ing C3 may have temporarily "woken" it up.
The 431 seems to need a minimum load; when an unbypassed opto LED is the sole source of current to the 431, the latter can hunt....
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Forum: Troubleshooting Power Supplies and Power Supply Design
03-03-2022, 09:04 PM
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Replies: 12
Views: 624
Re: 9v super basic wall wart issue
The 431 may be hunting.
Try a 150-1k resistor across the IR LED in the opto.
Points are marked in attached image.
Change the small cap on pri side to 22u/50v or 47u/50v.
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Forum: Troubleshooting Audio Equipment
03-03-2022, 12:53 AM
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Replies: 23
Views: 1,952
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Forum: Troubleshooting Power Supplies and Power Supply Design
02-24-2022, 04:15 PM
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Replies: 14
Views: 1,048
Re: PSU weaken - occasional reset
Just so you're not chasing a false lead- remember that after desoldering, if those caps are warm when you ESR test them, you can get a false OK reading.
Let them cool 30 min or so before testing...
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Forum: Troubleshooting Power Supplies and Power Supply Design
02-21-2022, 09:41 PM
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Replies: 14
Views: 1,048
Re: PSU weaken - occasional reset
Most likely, yes. Raidmax is known to use bad caps.
If PG is dropping out only with the tester connected, either the main output filters are nearly open, or bad small caps in the control ckts are...
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Forum: Troubleshooting Audio Equipment
02-16-2022, 10:06 PM
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Replies: 16
Views: 967
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