I think I was able to fix my computer's VGA display circuits (inside the PC motherboard). An old HP from the XP days, though it was upgraded to Win 7 (not by me). The problem was that, when scrolling quickly on a web page with Firefox, the VGA would go all black for a second or so. And it would then come back, along with a statement that the VGA drivers briefly crashed. Heard that dust clogging a VGA chip's heat sink could do this. I took the cover off the PC, and I immediately spot bulging caps in the neighborhood of the VGA chip!. 3 of them. Replaced them (I also added a ceramic surface mount...

Re: List of Bad Cap Manufacturers



Yep, had to replace one in a Netgear ethernet switch. 100uF @ 400V, 105C


One of the leads broke off when I was removing it out of the Netgear's power supply board (this board inside the switch's box, it's a 24 port box).

A bad case of radio frequency interference was cured by replacing this cap.

While I had the power supply under the knife, I replaced the other Ltec caps as well....

I was getting mild to bad RFI on the AM broadcast band, and lesser amounts on the amateur radio shortwave bands (hence the source of my user name here, it's my amateur radio callsign). After hunting it down by unplugging suspects, found it was my ethernet switch. Okay, took it out of service to figure out how to silence the RFI. Took the covers off, and after trying some additional powerline filtering (like those IEC metal bricks with internal coils and caps), noticed that the main power supply filter on the primary side of the switching power supply had a ruptured top! Well, need to replace...

Re: PSU Primary cap question



The supplies that are rated to accept 100V to 250V AC don't really do an "autoselect" like the switches on PC power supplies had. These supplies will just adjust their switching duty cycles to convert whatever the rectified input voltage to the desired output voltages (via the transformer).

Replacing the caps won't change the power supplies' average current demand off the powerline....

I was using a Linksys RV082 8 port router, but I wanted more ports, so I got off ebay a 13 port Linksys RV016 router. It has 16 ethernet jacks, but two of them are for WANs, one for a DMZ, and the other 13 are LANs for PCs and such. Many rooms in the house now have ethernet jacks (wifi around here is too congested and slow). Received it, got it running. Then a few days later the power supply dies. Seems the power supply input filter cap had gotten used to 120VAC in, and when I connected to 240VAC it eventually went bad and took out the bridge rectifier and fuse. The cap, 47uF 400V was bulging...

Re: bad 820uF 6.3v caps in HP pavilion a867c PC



The caps I arrowed in your mb picture and my picture of my mb are the ones I replaced. The replacements are 1000uF 10V 105C. And about twice the physical size as the old ones.

The bad caps:


The system's been stable since my last post last week....

A few weeks ago I changed some of the memory modules from 1/2 gig to 1gigs. To now have 3 gigs of ram. Well, now the system would occasionally freeze. Bad new memory? Maybe some SW I've been running doesn't play nice in the system? Well, I decided to pull the new memory and replace it with the old ones. But I noticed a pair of [B]green "Ltec" 820uF 6.3v caps[/B] had bulging tops. Right near the memory. Got out the tools and soldering iron, and found a couple of 1000uF 10v caps 105C as replacements. Noted which circuit board hole gets the negative side. Put the system back together and...

Re: List of Bad Cap Manufacturers

"SEC" brand, from China. Used in security cameras my previous company made (Videology), almost all blew up. 220uF @50V 85C IIRC. And I checked, no overvoltage condition involved. Tested a bunch connected to a power supply at about 47V, some started exploding after an hour and a half.