Recover corrupt bios? Hotswap+ wire+new PLCC socket???

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I corrupt a compaq motherboard during bios update.
Now the computer won't boot. I tried all the ami recovery procedures
and it still won't work.

The bios is a plcc 28-pin bios. It is soldered to the board.
I don't have a hot air station so i don't know how to desolder it.

I am thinking of the following way to recover the bios

1) find a 28pin plcc bios
2) drill some holes on the bios, so i can disable it and makes it dead
3 connect wires from the dead bios to a PLCC socket
4)find a good board that uses the same voltage, size and memory size
and do hotswapping.
5)boot the good motherboard
6)run uniflash
7)remove the good bios chip
8)put the dead chip(already connect to PLCC socket)
9)plug the PLCC socket to the corrupt PLCC chip
10)recover using uniflash

Will it work? Can the bios rewrite this way?

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

On Sun, 18 Nov 2007 20:45:53 -0800 (PST), wrote:

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At what point does it stop?  Sometimes, putting in a PCI
video card will allow onscreen video to see what it's doing.

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I think you just described how to do it, that you need hot

There is a substitute if you are very skilled, you can
either heat up each pin in turn and use a pick or fine knife
blade to pull up each pin at a time, OR you can use fine
wire snips to cut each pin at the chip and then individually
desolder each pin after the chip body is removed.

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IMO, drilling holes is very risky and should be avoided.

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Use Uniflash to flash the bios for this board, to a chip
installed in another board.  I mean after you boot the other
board, you hotswap the chip  you want to use and then
uniflash writes the bios to it.  

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LOL, I should read ahead more often.

Yes you can hotswap chips and flash with uniflash, I have
done it several times.  I think drilling holes in the
soldered-down EEPROM is too risky though, that you should
find a less risky way to remove it.  Even if a hot air
station is  out of the budget, a  hot air gun is less
expensive and you could practice on other parts to determine
the distance and duration of heating needed to melt the

In rare cases I have done something a bit different, that I
closely matched the size of a chip to a hole I cut out of
aluminum sheeting, then I placed that mask over the board to
shield it, so the heat from a  hot air gun or torch was
mostly heating up only that chip instead of the surrounding
area, and with forcepts or similar grasping the chip it was
immediatelly apparent when the moving heat source had heated
up the solder enough that it was melted.

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

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I wish you well with the idea of replacing the bios chip.

As an alternative approach, how much would a replacement motherboard cost?
Whilst probably not the cheapest option it might be the easiest and quickest
option, and you might eventually find that its the only way to get it
working again.
Brian Cryer

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

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My sentiments exactly, Brian Cryer. All this merry chitchat of
drilling holes, de-soldering/soldering willy-nilly pins, chips etc
with/without hot air gives me the creeps. No mention of solder-
suckers, MTM chip removers & all the detritus going where? For a few
bucks-worth of M'board ....peace of mind & a damned sight higher %-age
of a working PC at the end.
PS. Mental Masochism pops into mind. :-)

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

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Maybe the OP is just into self flagellation.

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

On Mon, 19 Nov 2007 06:31:41 -0800 (PST), sandy58

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I guess you'd have to desolder chips to realize it's not
really THAT hard to do it, but drilling is too uncontrolled
in most cases, perhaps with a jewlers' drill press the
height could be controlled enough but I'd be worried the bit
would catch on a pin and rip up a pad, plus with drilling
there's bit of metal being slug requiring a separate wash
step while desoldering might only require wiping the area to
remove some flux residue.

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

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De-soldering chips is like any other job. It is only easy if you have the
right tools for it.

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

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... and you know what you are doing.

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket???

On Tue, 20 Nov 2007 11:06:30 -0500, "RIAA"

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What would you call the right tools?  I have desoldered bios
chips in a pinch where I only used very basic tools.  

Soldering Iron w/fine conical tip


Dental Pick or X-Acto Knife with smallest default blade

Desoldering Braid (remove excess solder after chip is
removed, prior to soldering in new chip).

Flux (because desoldering braid didn't have enough in it,
and to allow high flux:solder ratio so less solder is

Basically with the minimum set of tools you heat the pins
one at a time and using the pick or knife slid between the
chip body and lead, it will bend the lead outwards and up
away from the pad as soon as the solder melts (applying
slight pressure while heating).

The catch is that bending the pins like this and heating up
next to the body of the chip may result in the original chip
being damaged.   Since this method is used when the chip is
not to be salvaged, after bending the pins up it is easier
to break them off by bending very sharply against the body
of the chip, because leaving none of an adjacent lead
sticking out of the chip body allows easier access to bend
up the successive adjacent leads.  

A hot air station is the better way to do it but many
people, including those who frequently work with
through-hold parts instead of surface mount, simply don't
have one and I wouldn't expect they want to buy one for a
single repair.

In some cases it might be desirable to replace the EEPROM
with a socket instead of soldering in the replacement chip.
*Some* EEPROM sockets can be soldered down with the same
(fine conical tipped) iron but they have a small plastic
piece in the center with very thin supporting plastic arms,
so that center piece can be easily snapped off so it can be
soldered from the top with the iron.  It is a little easier
to use solder paste, then just heat each pin slightly, later
checking for continuity between pins to be sure there are no
shorts.  I wouldn't advise this method on valuable equipment
but to save time or expense on something of less value it is
worth a try instead of paying someone more than the board is
worth to do the repair.

Something a couple of other posters overlook is that
sometimes a replacement board cannot be had, the same thing
does not exist (proprietary so a std. board isn't a direct
replacement, and OEM doesn't have any nor can it be found on
eBay/other surplus 'sites)  and without same OEM board the
software licenses are void (meaning more expense and time
spent) or possibly an in-place migration to a different
motherboard won't work and again more time spend trying to
repair an OS installation or even worse to have to reinstall
everything from scratch.  IOW the easy answer of "just
replace the board" to avoid spending a few minutes
soldering, does not account for all the further time and
expense to find, order, receive, then reconfigure or
reinstall the OS.  

That time is a bare minimum of several hours, in the end
it's really more a matter of whether you have steady hands
and soldering skills (not just holding an iron but
experience using flux, picks, 'sinks, etc as needed for a
particular job instead of taking the beginner's approach
which always seems to be "apply more heat and solder".

Re: Recover corrupt bios? Hotswap+ wire+new PLCC socket??? wrote:
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Get a new chip from . They can program it, if you provide
a file or a pointer to a file. They'll need to know what the existing
chip type is.

There is a solder material called ChipQuik. What you do with it, is heat
up one pin at a time on the existing device. Apply the Chipquik solder.
As the Chipquik solder mixes with the existing tin/lead solder, the melting
point will be reduced, closer to the Chipquik temperature. Chipquik melts
at 58 degrees Celsius (the mixture of original solder plus ChipQuik will
melt at some higher temperature).

Picture of an SMD1-ND kit. Includes flux and special low temp solder. /

How will that help ?

If you invert the board, and apply a gentle source of heat right to the chip, the
chip should fall off. This assumes you've been careful to "poison" the solder
that was applied to each lead. And that the device wasn't glued to the board in
the first place. (A really mean manufacturer would bend the leads to keep the
device in place. Assuming it is thruhole.)

There are some replacement sockets here, that could be soldered
back into place. How easy that is to do, depends on whether the thing
is thruhole or SMT.

Now, insert the provided EEPROM with the new code in it.

One guy who has used ChipQuik, claims he uses nylon dental floss, to
remove the molten material from between a lead and the PCB. I'd rather
take a chance on inverting the board, and just making the chip drop
that way.


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