Long-time lurker here, I really love the site and have garnered tons of very useful information. I've run into an issue with a motherboard that I'd like to ask some assistance from the brains here on the forum.
Because I know you all like pictures, here's the board I'm working on:
First, some background knowledge. I have reviewed the No POST FAQ Sticky... https://www.badcaps.net/forum/showthread.php?t=4810
This board was working, was running in a full-sized Raw Thrills SuperBikes arcade game. We had an issue with a bad BIOS battery, during the replacement we noticed the motherboard had caps that were severely bulging. They were a slightly different value than any I had in stock from previous motherboard work. So I ordered them. During the time the order was coming in, the game was up and running. Within a week, it died. The motherboard was bad. I had assumed it was the caps. Upon replacement of the most severely bad caps (and testing all of the others for bad ESR readings), I was only getting a momentary pulse of the fans when trying to boot.
Fast-forward to last night. I had left the bad motherboard on the shelf while ordering a replacement found on eBay. Replacement gets the game up and running, but I'd really like to get something out of the parts and time investment in this bad motherboard. Also, I really want to learn a bit more about troubleshooting these, so please humor me.
While this one was on the shelf, I jumpered the CMOS reset, and removed the battery. It sat that way for a few weeks. I started replacing some of the non-suspect (via ESR reading or visual inspection) caps. Upon completion of this process, I've got a board that will now keep the fans spinning, and respond to power-off requests by holding the power button down for 5 seconds. However, I still get no POST, no beep, no video (from on-board or PCIe cards). I have not tried a PCI card yet. Edit: I've also tried holding the Insert key on the keyboard while powering-on (read that this can clear the CPU configuration on this board). The keyboard blinks the Num Lock and Caps Lock, but not the Scroll Lock within the first second of boot.
I've replaced all of the large caps on this board. I've also replaced quite a few of the smaller ones at this point. Here's a glory-shot for those picture seekers out there (and to break up this text wall):
I'm assuming that the bad caps killed something else on the board (duh), but can't seem to figure out what. I've verified that all of the FETs seem to be doing their jobs. I'm getting a voltage out that is different than what goes in (all are either 10, 3.3, 1.4). I think I found some 5v mixed in as well. I've tested voltages at the DIMM sockets, and found 1.3 and 2.6). The voltages are absolutely stable. Naturally the voltages coming in the ATX plug are also perfect and rock stable (using a known-good high quality power supply on the bench). I've also tested the voltages on the cap legs, and am getting rock-solid common voltages.
At this point, I'm looking for what the next step should be. I'd like to swap CPUs, but am hesitant to do so as I don't want to kill a CPU. That said, I've reviewed the CPU Killer FAQ item at https://www.badcaps.net/forum/showthread.php?t=3024 and the associated VRM testing recommendations at https://www.badcaps.net/forum/showthread.php?t=600 . It's my belief that this motherboard is "within spec", at least now that the caps are replaced. I have no tests from prior to indicate if it was a CPU killer.
I'm thinking the safest method would be to take the suspect CPU and put it in a known-good motherboard? I'd think the other way around puts a new CPU at-risk... I'd think a bad CPU less likely of frying a good motherboard. Can someone confirm?
Also, any other suggestions on what to try next?
Thanks again for reading this tirade.
Because I know you all like pictures, here's the board I'm working on:
First, some background knowledge. I have reviewed the No POST FAQ Sticky... https://www.badcaps.net/forum/showthread.php?t=4810
This board was working, was running in a full-sized Raw Thrills SuperBikes arcade game. We had an issue with a bad BIOS battery, during the replacement we noticed the motherboard had caps that were severely bulging. They were a slightly different value than any I had in stock from previous motherboard work. So I ordered them. During the time the order was coming in, the game was up and running. Within a week, it died. The motherboard was bad. I had assumed it was the caps. Upon replacement of the most severely bad caps (and testing all of the others for bad ESR readings), I was only getting a momentary pulse of the fans when trying to boot.
Fast-forward to last night. I had left the bad motherboard on the shelf while ordering a replacement found on eBay. Replacement gets the game up and running, but I'd really like to get something out of the parts and time investment in this bad motherboard. Also, I really want to learn a bit more about troubleshooting these, so please humor me.
While this one was on the shelf, I jumpered the CMOS reset, and removed the battery. It sat that way for a few weeks. I started replacing some of the non-suspect (via ESR reading or visual inspection) caps. Upon completion of this process, I've got a board that will now keep the fans spinning, and respond to power-off requests by holding the power button down for 5 seconds. However, I still get no POST, no beep, no video (from on-board or PCIe cards). I have not tried a PCI card yet. Edit: I've also tried holding the Insert key on the keyboard while powering-on (read that this can clear the CPU configuration on this board). The keyboard blinks the Num Lock and Caps Lock, but not the Scroll Lock within the first second of boot.
I've replaced all of the large caps on this board. I've also replaced quite a few of the smaller ones at this point. Here's a glory-shot for those picture seekers out there (and to break up this text wall):
I'm assuming that the bad caps killed something else on the board (duh), but can't seem to figure out what. I've verified that all of the FETs seem to be doing their jobs. I'm getting a voltage out that is different than what goes in (all are either 10, 3.3, 1.4). I think I found some 5v mixed in as well. I've tested voltages at the DIMM sockets, and found 1.3 and 2.6). The voltages are absolutely stable. Naturally the voltages coming in the ATX plug are also perfect and rock stable (using a known-good high quality power supply on the bench). I've also tested the voltages on the cap legs, and am getting rock-solid common voltages.
At this point, I'm looking for what the next step should be. I'd like to swap CPUs, but am hesitant to do so as I don't want to kill a CPU. That said, I've reviewed the CPU Killer FAQ item at https://www.badcaps.net/forum/showthread.php?t=3024 and the associated VRM testing recommendations at https://www.badcaps.net/forum/showthread.php?t=600 . It's my belief that this motherboard is "within spec", at least now that the caps are replaced. I have no tests from prior to indicate if it was a CPU killer.
I'm thinking the safest method would be to take the suspect CPU and put it in a known-good motherboard? I'd think the other way around puts a new CPU at-risk... I'd think a bad CPU less likely of frying a good motherboard. Can someone confirm?
Also, any other suggestions on what to try next?
Thanks again for reading this tirade.
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