George Macdonald wrote:
> On 23 Oct 2005 09:04:17 -0700, (E-Mail Removed) wrote:
>
> >
> >George Macdonald wrote:
> >> On 22 Oct 2005 12:45:11 -0700, (E-Mail Removed) wrote:
> >>
> >> > I put DDR RAM module into my socket, and when I turned the computer
> >> >on, 2 of the contacts got burnt. I think it's 184 pin RAM and it's
> >> >pin/contacts 86 and 78. That is the 8th and 16th contact counting
> >> >from the 93rd contact towards the first. Interestingly, on a diff
> >> >make/model of mobo, diff make ram , diff PSU, I had the same problem.
> >> >the exact 2 same contacts got burnt.
> >>
> >> 93rd? There are 92 pins and pins 85 and 77 are Vdd & Vddq respectively.
> >>
> >> >The events before, were, i restarted the comp (via windows) and it
> >> >reset but wasn't starting. I took a (the only) RAM module out. put it
> >> >the other socket, and it was fine.
> >> >
> >> >THen i restarted through windows, and it reset but wouldn't start. I
> >> >unplugged te power. took the RAM out of the socket put it back in hte
> >> >same socket. turned on the power. switched it on, and hey presto, i
> >> >smelt burning and saw my ram module had burnt out.
> >> >
> >> >anybody got any ideas what the problem is, how to diagnose?
> >> >I know i'm going to h ave to take the mobo back. But, this has happened
> >> >once before and ideally i really want to be able to detect a problem
> >> >like this before it hits and takes out my RAM too. I want to at least
> >> >detect what caused the problem.
> >> >
> >> >It may be of interest, I tested the Voltages coming out the ram
> >> >sockets with a multimeter (could i have electricuted myself from
> >> >that? e.g. if a current surge caused the problem)
> >> >On a working board of the same kind , I got voltages of 2.6v and 1.3v,
> >> >depending on which contact i touched.
> >> >On the now screwed up board with the no doubt partially burnt socket I
> >> >got voltages of 0vv often and sometimes 0.3v . So not suprisingly,
> >> >the mobo seems buggered, but this is of course after the event.
> >>
> >> I've no idea what to expect on those pins if the slot is empty, i.e. no
> >> power-on sequence has happened.
> >>
> >> >I spoke to a guru electrician, he said maybe i could check a capacitor
> >> >with a 'good LCR meter'. And he said a multimeter won't pick up a PSU
> >> >swurge because it's all in the switching, and it's so fast the
> >> >multimeter wouldn't pick it up. he said i'd need an oscilloscope.
> >> >Well, i'm not electronics guru.
> >> >But you are RAM gurus
> >> >
> >> >I'm thinking maybe you chip, MOBO and RAM specialists gurus and experts
> >> >have some idea of what happened, it was *the exact same 2 contacts *
> >> >that got burnt as on a diff comp i once had! So this must be a standard
> >> >prob. And that last time they burnt when I tried to turn it on. So,
> >> >v. similar to this time round.
> >>
> >> Check the electrolytic capacitors on the mbrd for swelling tops or leakage
> >> near the base. There was a slew of mbrds a couple of years ago which had
> >> bad caps: http://www.niccomp.com/taiwanlowesr.htm. For examples:
> >> http://www.badcaps.net/ & http://www.motherboardrepair.com/.
> >>
> >> --
> >
> >
> >Thanks, you got it, it is pins 85 and 77, VDD and VDDQ respectively, as
> >you said.
> >
> >the capacitors aren't leaking or bulging or tilting.
> >
> >So, the prob is still undiagnosed, and i'm not sure how i'd avoid or
> >detect and prevent it from happening in the future.
> >
> >The RAM module whose 2 contacts got burnt had chips made by Infineon.
> >I have heard they're a decent make of chip.
>
> The DRAM chips themselves would not likely be suspect here at all - if
> anything the DIMM and its ancillary components might.
>
> >On my old system where the samae thing happened, I think the RAM module
> >cheap, like RAM BO or RAMBO RAM .
>
> AFAICT RAMBO, or RAM BO is a brand name used by a DIMM & other memory
> product, mfr called Muse in Hong Kong - never heard of them before but I
> tend to stay with mainstream mfrs, usually Crucial. Back in the PC-100
> days, you used to be able to get away with generic DIMMs but this is no
> longer the case IMO - the specs are so tight on DDR-DRAM that it's not
> worth the risk.
>
> >The RAM was seated fine.
> >
> >I don't know if iti's bad RAM, bad MOBO or bad PSU or bad AC/Mains
>
> Whatever failed I'd have thought all modern mbrds would/should have
> over-voltage and over-current threshold protection against this kind of
> thing but I'm no expert. No sign of blistering or burnt traces on the
> mbrd? Was this a mainstream mfr mbrd?
>
1st time it happened: PCCHIPSUSA motherboard and RAM BO RAM. PSU was
a standard Antec PSU (I think) which I still use.
2nd time it happened: Asus motherboard P4P8T MBRD (ASus T2 'barebones'
system - RAM was from an old ASus T2 that had 1 and later 2 bad IDE
connectors!
The RAM in the old Asus T2 system which I reused, was not supplied by
Asus. THe details on it are
P/N PCM-RAM-D33F512S <-- written on a yellow sticker with a barcode
on it.
and the chips say Infineon on them.
I don't know who made the module. But I guess they were good enough to
put Infineon chips on it.
Regarding voltage protection. IT may have had voltage protection. The
comp was working fine, I wanted to restart it just to confirm that the
CPU temperature wasn't going past 50 degrees. So I restarted it and it
reset but didn't start up. blank screen. Maybe that was voltage
protection. When I unplugged it and put the RAM Back in, maybe it
'forgot' that the voltage (or current?) was too high, and it blew. I
wouldn't know te electronics behind it.
BTW, is it possible that high current did it? I will be checking RAM
sockets next time a computer resets but start up or beep or post.
So, I would like to know if i'd injure myself testing the voltage,
maybe i'd get a high voltage or current through me.
The Modules 2 'power supply pins' Vdd and VddQ are totally browned.
Can switching PSUs get surges that high? 'cos if so, i shuldn't be
testing connectors with a multimeter at all.
thanks
> >I'm sure this has happened to more ppl, since it has happened to me
> >twice. Hopefully, next time it happens, people will put the incident
> >on usenet! At least this post comes up for burnt ram , with the given
> >pins. It's a start!
>
> First I've heard of this kind of incident around here.
>
> --
> Rgds, George Macdonald