Recapping did not help :(

[zorba128]

Hi everyone.

My FS ESPRIMO P5916 (D2314-A3 motherboard) stared to have problems.
It appeared that OST RLA 6.3V, 3300 uF is bulged. I've replaced it with Jamicon MZ - I'm not really sure if it is any better now (sometimes works for a while, sometimes keeps restarting every few seconds).
After that tried resoldering joints again - did not help.

Motherboard layout is here
here.

Failed cap is the blue one near memory sockets. There are no converter elements nearby, nothing seems fried.

Remaining caps on motherboard:
OST RLX 16V 1500uF near powe supply socket (my motherboard has one, the one from FS website seems to have two in place).

Near cpu socket - all aluminium with red labels (752, 821, 2.5V), 820uF/2.5V, no vent/K-cut on top (non liquid electorolytics?)

PSU (BTX FS NPS-230 EBB) voltages seem fine, no visibly broken caps inside.

Generally pc restarts itself few seconds after power on; however
- it all started by sudden reboot while it was in sleep - so at this moment there was almost no power consumption
- sometimes "power on" led on front panel is on, sometimes if off
- sometimes replugging power cable causes motherboard to try to start up, sometimes does nothing
- without memory in slot, it beeps out error code and shuts down itself
- i can see what is going on by watching front led, PSU relay sound and led on motherboard; however at this moment all the combinations
of behavior seem possible

Any tips? Probaby I should check it with other PSU, but I don't have BTX one to try...

regards,
Marcin

[PCBONEZ]

Re: Recapping did not help

Jamicon are junk AKAIK.

You need to replace ~ALL~ the OST with good Jap caps with appropriate ESR and Ripple.
OST are famous for failing without bloating at all so if one was bloated you can be pretty sure some more (or all) of them are bad.
.
That might not be the whole problem, but there's a good chance it is, and you aren't going to get anywhere trouble shooting with bad caps on the board.
.

[zorba128]

Re: Recapping did not help

Hi

I've just finished replacing all the 6.3V, 1000uF OST RLP - replaced with Sanyo WG, 10V/1000uF.

I don't think anything changed .
If PC is started cold, it works for a while. After that XP tries to shut it down (probably thermal or volatage warning - didn't found exact reason so far). After that motherboard starts rebooting.

What I could try:
- purchase some other caps for ones I've replaced at the very beginning (bulging OST RLA 6.3V 3300 uF near radiators, and OST RLX 16V 1500uF near power socket)
- replace smaller caps (there are still some 470uF, 33uF)
- replace 2.5V ones

Any advices?

thanks,
marcin

[RJARRRPCGP]

Re: Recapping did not help

"XP trying to shut it down"

-Is XP logging you off? Does Windows suddenly tell you that you're being logged off? That's not a hardware issue. Sounds more like unknown malware.

And when the PC reboots, it's probably Windows rebooting on purpose, because the Windows kernel got pissed off.
(stop error)

[zorba128]

Re: Recapping did not help

"XP trying to shut it down"
Is XP logging you off? Does Windows suddenly tell you that you're being logged off? That's not a hardware issue. Sounds more like unknown malware.

Yes, XP logs me off. But I think this is related to motherboard - as after that subsequent restarts appear few seconds after each other (during POST).
Similarly - it sometimes starts restarting when in bios setup. Probably after something gets warm (caps?) issue appears.

[zorba128]

Re: Recapping did not help

Hi

Tried with another FS PSU (have to give it back...) - as long as I was on - it seemed stable.
On low voltage side of PSU:
- 1x 16V 1500u
- 3x 6.3 2200u
- 2x 6.3 1000u
- 2x 6.3 470u
- some other, smaller ones
all LTEC LZG, none seem bulged/leaking (brand from red list)

HV: proably LTEC also (need to be unsoldered in order to read label).

I'm wondering if I can verify PSU somehow (ripple voltage?) before trying to fix it (still not really sure if everything is ok with motherboard...).



marcin

[PCBONEZ]

Re: Recapping did not help

You need an O'scope to check Ripple.
.
Either recap or replace the PSU.
.
Attached LZG data sheet so you can check specs.
.

[zorba128]

Re: Recapping did not help

Still fighting. I think that PSU is/was fine. Finally got scenario:
- if starter after being turned off for a long time - works fine for several hours.
- after that I've turned it off
- after an hour or so - it started without any reason
- now it restarts during post. I've just replace PSU - still behaves same

So - PSU seems fine, and problems seem related to standby voltage (as first time issue occured when most of motherboard and psu was off...).

Anyone encountered such behavior?

regards,
marcin

[PCBONEZ]

Re: Recapping did not help

When you push the start button what it does is temporarily ground a pin on an IC chip.
(Usually the chipset.)
That pin is usually powered [to something like 1v] from +5vsb in soft-off.
.
If it's starting all by itself that means either you have an intermittent ground or +5vsb is occasionally dropping so low that pin 'thinks' it's grounded.
.
A shorted cap or one that won't stay changed is one possible cause of that.
It would be a small cap if on the mobo.
Would probably be the cap on +5vsb output if in the PSU.
- Other non-cap problems can cause it too.
Like maybe the +5vsb transformer is getting flaky or there's a cold solder joint that breaks a connection.
.

[zorba128]

Re: Recapping did not help

Hi

That seems to match behavior I've described earlier - windows wanted to (gracefuly) log me off - just as if power button was pressed.
Power button is disconnected already - not it's fault .

I think the cold joint might be the idea - but I'm not sure what to do with it... Resoldering whole motherboard doesn't seem reasonable .
Maybe I'll try to use some freezing spray - but not really convinced this will lead me anywehere.

Tomorrow I'll get it out again to finf 6.3V caps that were not replaced yet - including smaller capacitances.

marcin

[PCBONEZ]

Re: Recapping did not help

A cold joint would be more likely in the PSU.
.

[zorba128]

Re: Recapping did not help

Testing with two PSUs - on both - same behavior - so it seems this is motherboard related.

[PCBONEZ]

Re: Recapping did not help

Have you check the actual switch isn't fubar?
Does happen now and then.
.
You can disconnect the power switch and temporarily use the reset switch there instead to see if the problem goes away.
[Same kind of switch.]
.

[zorba128]

Re: Recapping did not help

Thought about it - switch is already disconnected.

[zorba128]

Re: Recapping did not help

Removed motherboard once again in order to look for short circuts or cold joints. I've found this:

Near almost every through-hole joint there is a small drop of tin; maybe one of them causes problems?

marcin

[PCBONEZ]

Re: Recapping did not help

Good catch!
Look for any that are bridging traces.
(I see one that might be between the 8th from bottom pins in the right two rows..)
-
Should clean up with que-tips and isopropyl alcohol.
.

[zorba128]

Re: Recapping did not help

No luck... I'm running out of ideas .

marcin

[PCBONEZ]

Re: Recapping did not help

Have you tried threatening it with a sledge hammer?

Try removing and reinstalling the CPU and RAM in the hopes there is a bad connection in the socket or slots.
.