What happens if I replace PC mobo caps with much higher capacitance? - Page 1
Forum section: electronics / beginners

author: AreTwoDeeTwo
author_rank: Newbie
timestamp: July 05, 2020, 09:58:38 pm
content: UPDATE: Cleaning off thermal compound and reseating CPU fixed the problem. Suspect the compound was shorting something (like those gold circles on the top front of CPU) since quite a bit leaked off the heatspreader. No more freezing etc.What will happen if I replace three 560uf capacitors on my motherboard each with 1000uf capacitors (Nichicon UWT0J102MNL1GS)? They are all smd electrolytic capacitors (both the old ones and the Nichicons), and they are mostly to the right of the CPU socket, near the 24-pin ATX connector. I know people recommend not to go above +20%, but that's for liability reasons, what would actually happen in all likelihood? Does anyone have any experience with going way above the original capacitance (while keeping voltage equal or higher)?PC has becoming unstable lately in the past few months, gets into boot-loops if you restart too soon after a freeze, and in more recent weeks it now always freezes when stress-testing in prime95, and I've narrowed it down to the motherboard or CPU (extremely unlikely).ASUS P8H61-M LE/CSM R2.0(10x) 820uF 3V 3mm-spacing : closest surrounding the CPU socket, these I will definitely replace first and then test if the instability is gone(5x) 560uF 4V 3mm-spacing : mostly to the right of the CPU socket, near the 24-pin ATX connector, couple of them below the PCI-e slots which I won't bother with(4x) 270uF 16V 4.5mm-spacing : further out left (near VRM) and above (near CPU fan connector) of the CPU socket, will try some crap-brand 330uF caps if instability remains(2x) 100uF 16V 2mm-spacing : at the bottom left of the motherboard near a bunch of headers, don't think I'll bother replacing these unless instability remains as a fifth and final step before buying another used mobo off ebay

author: wizard69
author_rank: Super Contributor
timestamp: July 05, 2020, 10:32:37 pm
content: I would imagine it is going to depend upon what the caps are doing. Going larger might not hurt on a linear power supply, on a switcher it could impact performance depending on what it is doing in the circuit.

author: sahko123
author_rank: Frequent Contributor
timestamp: July 05, 2020, 10:38:22 pm
content: Sometimes stuff like his can be because of hard drive faults or the power supply itself. But if your changing the caps in a motherboard change them for the same value they're those values for a reason so best not screw with it replace some with new ones of the same value.

author: amyk
author_rank: Super Contributor
timestamp: July 05, 2020, 11:25:27 pm
content: The 16V ones are on the 12V rail and provide bulk decoupling, increasing their values will not hurt anything. The 3V and 4V are CPU Vcore and may affect the transient response of the VRM if you change their values (or ESR) too much.Your mobo was made well past the "capacitor plague" era, so I would not suspect the caps. Is it an overclocked system? Have you tested the RAM?

author: wilfred
author_rank: Super Contributor
timestamp: July 06, 2020, 12:03:26 am
content: A much easier first option to try for a problem like this is to try another power supply. Try removing all non essential peripherals, especially the power hungry ones, and see if that helps. Try running a memory test. Some bioses have this built in.If it is the power supply then trying anything else first will be inconclusive for intermittent faults.You will probably make things worse by changing probably good capacitors. If it is the caps then replacing them with equivalent ones will be good enough. MB makers have decades of experience so you can assume they picked the correct ones.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: July 06, 2020, 12:07:04 am
content: Prime95, are you an overclocker?I'm tending to agree with @amyk @wilfred and @shako123. The instability you describe seems more like a DDR timing or front side bus issue. Have you checked the bios settings are still where you expect them to be? Sounds stupid, but does the coin cell need replacing?

author: AreTwoDeeTwo
author_rank: Newbie
timestamp: July 06, 2020, 03:40:04 am
content: Quote from: amyk on July 05, 2020, 11:25:27 pmFor the 560uF 4VSMDcapacitors (unknown brand) on the motherboard, I have 1000uF 6.3V Nichicon SMD electrolytic capacitors (datasheet) and 470uF 16V JB radial electrolytic capacitors (datasheet) that I can replace them with, which of these two do you think would be safer?Nichicon is a more trusted brand and they are SMD, but the JB's are closer to 560uF, just barely within -20%.EDIT: Nevermind, I mixed up "SMD" with "solid" capacitors, I can only use radial leaded ones.Everything below I typed you can ignore reading, they are lesser details that are probably boring to most of you.The only overclocking I did over the years was having the "Turbo Boost" setting on for my i7-3770S CPU which is enabled by default on the BIOS/UEFI. As for RAM, a few weeks ago when prime95 v26.6 did not completely freeze the PC within a minute like it does now, I did blend test for 30 mins with no errors, and I also did one pass of memtest with no errors.I am not an overclocker, I am an undervolter, I like my PCs running cool and quiet, I'm the type of person who reapplies the thermal compound on the CPU meticulously several times with differing amounts and spreading techniques and tests the CPU on prime95 v26.6 small FFT for 5 minutes each time until it never goes past 65C with the fan setting in the ASUS BIOS set to "Silent".I don't think anything's wrong with the CMOS battery, it's never forgotten any of my BIOS settings or failed to save any.I noticed my surge protector (CL-208AV) LED is red instead of green, so a power surge may have damaged the motherboard, who knows.Symptoms:The symptoms gradually become worse. A couple months ago the only issue was once a week all of a sudden the USB wired mouse and keyboard would both turn off and on at the same time (without the Windows USB disconnection sound you typically hear) repeatedly in mostly random intervals (0.5 to 1.5 secs) for about a minute like it's playing tricks on me. I remember I could be watching a YouTube video and it was still playing smoothly 60fps 720p but my mouse cursor would be skipping around if I tried moving it and the keyboard numlock LED would be flickering off and on as well. This would last anywhere from half a minute to a couple minutes, and then this oddity would stop and the PC would continue to run perfectly fine after that.Last month, it has progressed to keyboard & mouse flickering, with eventually a total freeze after a minute or so of it goofing around with the kb & mouse of the OS, forcing you to restart or shut off by holding one of the buttons for 5 seconds, and this would become a more daily occurrence. The freezing does not give any useful error message in Windows' Event Viewer, just that it reports an "unexpected shutdown". I also noticed that if I ran prime95 v26.6 small FFT CPU stress test (no errors), and then stopped it, the OS would freeze within a minute after stopping. That never happened before. I suspected it didn't like the vcore voltage fluctuation so I upped the offset voltage +10mV.In more recent weeks it doesn't bother to play tricks with the kb&mouse, it just freezes. Doesn't matter whether it's idle, light load or under load. Also p95 small FFT now crashes and restarts the Intel iGPU driver for a couple seconds (I use the iGPU for my secondary monitor) within half a minute or so of stress test and then within a minute it freezes the PC. Or sometimes p95 just freezes immediately without crashing and restarting the Intel iGPU driver.Now the situation is that prime95 is guaranteed to freeze the OS now, and freezing is a daily occurrence. If I reboot immediately after a freeze, it almost always gets stuck in a boot loop (turns on for 3 secs, turns off, waits 5 seconds, then repeat). If I wait 10 seconds before rebooting then it's like 66% chance it gets stuck in a boot loop instead of making it to POST, then like 50% chance after 30 seconds, and then like 10% chance if I wait 1 minute. I notice that if I reboot soon after a freeze and manage to get to BIOS/UEFI settings, if I stay on BIOS long enough, maybe 20 seconds or so, the BIOS starts responding quite slowly to my keyboard presses, it feels laggy, and if I try to save & exit, it just turns to a black screen with the BIOS/UEFI cursor and freezes for like 10 seconds and then turns off, and then reboots after 5 seconds and gets stuck in a boot loop. The BIOS does always save though even if it starts lagging and enters a boot loop after exiting, so it can't be a CMOS battery problem. If I wait like 5 minutes after a freeze, the computer gets past POST but it usually freezes at the "Starting Windows" screen. If I wait 10-30 minutes, it usually gets past "Starting Windows" but freezes right after everything loaded (taskbar, windows explorer, network, sound etc.). Anyway the workaround now is I have to wait at least a few hours with the computer turned off until I turn it on again and can expect BIOS or Windows to be running stable and smoothly for a day or two (short of doing something very CPU-intensive like prime95 and probably video encoding, since that's guaranteed to freeze now). So basically I could have this PC running during the day, have it turned off at night, and not notice this PC has a problem other than the guaranteed freeze if I stress the CPU too much.Also, 4 years ago I had this i7-3770S undervolted -115mV (offset voltage), and it would run stable for months, and every few months after it would freeze I would bump it up +10mV. Now I have it at +15mV above stock, and I have LLC at high (50%) because I think it seems more stable like this. If I try to undervolt back down to -20mV or more, I'm more likely to get a clock interrupt BSOD (which I didn't use to get a couple years ago) instead of a freeze. Increasing voltage any further doesn't seem to make any difference to occurrence of the freezing, it doesn't improve anything if I do +60mV offset, and stock voltage or undervoltage seems to freeze sooner or cause clock interrupt BSOD if you go low enough. Initially I thought this was all CPU degradation, but I am skeptical because I've never heard of non-OC'd (unless you count Turbo Boost as an OC) CPUs getting bad this quickly, so I suspect something on the motherboard has degraded.Removing CMOS battery and/or unplugging power cable and pressing the power and reset buttons several times to discharge the system appears to have no effect on expediting getting past the boot loop issue or making the system stable, simply waiting for maybe a few hours appears to be the only "cure" to have it running relatively stable for a day. It's as if there is some component on the motherboard or the CPU (doubtful) that has deteriorated to the point that it cannot handle prime95 at all anymore, and it needs to "recharge" like a living organism or battery after a day of work, you can't wake it up too soon or it'll fail to function properly sooner, you need to give it some hours of continuous rest until it's ready to function properly.Tried these BIOS settings and PC configurations, none of them made any difference:Made sure all cables and RAM sticks were firmly secureRemoved all dust, including in the PSU which I opened (with the usual precautions, one-hand rule, not touch anything metal inside, etc.) to check whether any bulging/leaking capacitors and to remove dead spider with wooden chop stickTried no HDDs, booted Kubuntu live usb, still freezes like in WindowsTried different PSU, no HDDs, no dGPU, booted Kubuntu live usb, still freezes like in WindowsDisabled Turbo Boost (I now have it always disabled, since it seems to make the PC freeze sooner)Reset BIOS several times by removing CMOS batteryReflashed BIOSTried all LLC settings (Auto, Medium, High, Very High, Extreme)Tried offset CPU voltages (-115mV, -80mV, -25mV, Auto, +15mV, +30mV, +50mV, +70mV)Tried manual CPU voltages (0.900V, 0.950V, 0.980V, 1.000V, 1.050V, 1.080V)Disabled SpeedStep and all C statesDownclocked with CPU multiplier locking it down to 1.6GHz (16x100 = 1.6GHz, instead of 31x100 = 3.1GHz default)Downclocked with BCLK (96 is the lowest I could get it to POST, from 100 default)Downclocked RAM from 1333MHz down to 1000-ishIncreased DRAM voltage +25mVIncreased PCH voltage from 1.050V to 1.090VDisabled iGPU and used dGPU onlyRemoved dGPU and used iGPU onlyChecked if surge protector still has surgeYou could have this PC at 1.6GHz downclocked, 1.080V CPU manual voltage, underclocked RAM from 1333 to 1000ish MHz, +25mV DRAM, +40mV PCH, no HDDs, different USB keyboard & mouse and using different USB ports, disabled Speedstep and C states, high LLC (50%), a different PSU, dGPU (GTX 960) removed, booted into a live USB session of Kubuntu 20.04, and it would still end up freezing exactly like in Windows regardless whether it's idle or under load.Based on these tests, I think the problem is with the motherboard or the CPU. I ordered some thermal paste since I ran out of it and I will test a spare G3258 CPU on this motherboard to see if it also freezes on prime95 etc. to rule out the i7 CPU, then I will start replacing the capacitors starting with the 820uF 3V ones around the CPU socket with 1000uF 4V Nichicons, test that, then work my way to replacing the 270uF 16V and then the 560uF 4V caps if still unstable.PC Specs:ASUS P8H61-M LE/CSM R2.0 (BIOS v1414)i7-3770S, will test G3258 in a few days when thermal compound arrives2x8GB DDR3-1333CX430, also tested DX-400WPSGTX960 2GB for primary monitorIntel iGPU for secondary monitor3 HDDs (tried with them unplugged, on Kubuntu live usb)5 low-RPM case fans (1 intake, 1 exhaust, 2 side in front of GPU, 1 in front of HDDs)CM 212 EVO CPU heatsink (1 Noctua push fan, 1 CM pull fan)

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 06, 2020, 09:02:44 pm
content: 1) I would check PSU el- caps with ESR-tester first.2) As I can see from photos this MB have all solid-caps in power lines (as all new MBoards). It is very unlikely them to fail. You want to replace them with usual wet elcaps - that will make things worse.3) All cheap PSU don't use solid polymer caps so they are prone to fail as it was always.