I have an IBM Thinkpad A20m laptop (2628-4UU) that failed last evening
with the same symptoms that literally hundreds of others have reported
over the last few years. Mine had been running fine, but I went to
power it up and, once it got to the Windows desktop it froze. Powered
off, then tried powering on again. Unit comes on when power is
pressed (HD spins up, all lights flash on then go off except for
power, I can hear the CPU fan running). No POST, no boot, black
screen.

I replaced the CMOS battery, reseated everything, yada yada yada. The
thinkpads.com web forums list a possible cause as a failure of one (or
both) chips in the dc-dc power section on the mainboard. These are
the Analog Devices ADP3421JRU and ADP3410KRU ICs. This is supposedly
due to a design flaw. Some people also say to change three MOSFETs
(IRF-7811) as well. Some report success, others don't.

It seems to me that by simply replacing the chips you're not fixing
the problem. SOMETHING caused the chips to fail as there wasn't (to
my knowledge, anyway) a bad run of those chips. Bad capacitors in the
circuit, maybe? Bad resistors, diodes ...? People ARE apparently
fixing the boards, as dealers will sell you refurbished ones or will
fix your broken unit.

So, what's the secret? Which components are routinely replaced during
the course of one of these repair jobs?
** To respond, remove the crap from my addy... **

prc1 wrote:
I have an IBM Thinkpad A20m laptop (2628-4UU) that failed last evening
with the same symptoms that literally hundreds of others have reported
over the last few years. Mine had been running fine, but I went to
power it up and, once it got to the Windows desktop it froze. Powered
off, then tried powering on again. Unit comes on when power is
pressed (HD spins up, all lights flash on then go off except for
power, I can hear the CPU fan running). No POST, no boot, black
screen.

I replaced the CMOS battery, reseated everything, yada yada yada. The
thinkpads.com web forums list a possible cause as a failure of one (or
both) chips in the dc-dc power section on the mainboard. These are
the Analog Devices ADP3421JRU and ADP3410KRU ICs. This is supposedly
due to a design flaw. Some people also say to change three MOSFETs
(IRF-7811) as well. Some report success, others don't.

It seems to me that by simply replacing the chips you're not fixing
the problem. SOMETHING caused the chips to fail as there wasn't (to
my knowledge, anyway) a bad run of those chips. Bad capacitors in the
circuit, maybe? Bad resistors, diodes ...? People ARE apparently
fixing the boards, as dealers will sell you refurbished ones or will
fix your broken unit.

So, what's the secret? Which components are routinely replaced during
the course of one of these repair jobs?
** To respond, remove the crap from my addy... **

Never heard of this myself (have 2 thinkpads...older than yours,
though). Symptoms sound like memory failure. How much installed? If one
stick, remove it and see if you get a POST screen...If 2 sticks, try
removing one and then the other. Sony had a problem with cold solder
joints in the RAM sockets. Maybe they weren't the only ones.

webpa wrote:

prc1 wrote:
I have an IBM Thinkpad A20m laptop (2628-4UU) that failed last evening
with the same symptoms that literally hundreds of others have reported
over the last few years. Mine had been running fine, but I went to
power it up and, once it got to the Windows desktop it froze. Powered
off, then tried powering on again. Unit comes on when power is
pressed (HD spins up, all lights flash on then go off except for
power, I can hear the CPU fan running). No POST, no boot, black
screen.

I replaced the CMOS battery, reseated everything, yada yada yada. The
thinkpads.com web forums list a possible cause as a failure of one (or
both) chips in the dc-dc power section on the mainboard. These are
the Analog Devices ADP3421JRU and ADP3410KRU ICs. This is supposedly
due to a design flaw. Some people also say to change three MOSFETs
(IRF-7811) as well. Some report success, others don't.

It seems to me that by simply replacing the chips you're not fixing
the problem. SOMETHING caused the chips to fail as there wasn't (to
my knowledge, anyway) a bad run of those chips. Bad capacitors in the
circuit, maybe? Bad resistors, diodes ...? People ARE apparently
fixing the boards, as dealers will sell you refurbished ones or will
fix your broken unit.

So, what's the secret? Which components are routinely replaced during
the course of one of these repair jobs?
** To respond, remove the crap from my addy... **

Never heard of this myself (have 2 thinkpads...older than yours,
though). Symptoms sound like memory failure. How much installed? If one
stick, remove it and see if you get a POST screen...If 2 sticks, try
removing one and then the other. Sony had a problem with cold solder
joints in the RAM sockets. Maybe they weren't the only ones.

Being another victim of this problem - an A21m to be exact - I can
definitely say it's not a memory issue. It's a mainboard component
failure. The speculation seems to surround component failure in the
power management circuits on the main board. It's also reported a lot on
the T20 series as well. When it happens the system won't even get to a
POST - how could it be a memory failure? Hit the power switch - all five
status LEDs light, then they all go out except for the power on status
LED. Any maybe you hear the CD ROM drive spin up for two seconds. That's
it... You don't even get a screen display, or anything else. Keep trying
that and if you are lucky you will get to a POST. And then if you are
really lucky you might get into the BIOS long enough to disable all
power management options - before if locks up hard. That will help
alleviate the symptoms somewhat. You might get the thing to power on
more consistently. But not enough to prevent the system from locking up
hard within 5 minutes.

It went to an authorized IBM repair center. They tested the RAM and
everything else. All they had to say was "main board failure." And IBM
wanted $999.00 to replace the main board on a computer I paid $799.00
for.

I thought ThinkPads were rock solid. But after this experience... If you
google "dead IBM thinkpad", well, see what pops up.

Now I have to figure out exactly what main board I need for this thing.
The part number listed at IBM's web site doesn't match the unit I have
regarding the on board video system...

Rick

I remember the big "bad capacitor" fiasco a few years back, and was
thinking...I haven't pulled mine apart to check the mainboard yet (but
I will this weekend) but I wonder if there could be some bad
electrolytic caps on it? The A2x series are around that vintage.



On Fri, 19 Jan 2007 19:36:59 -0400, Rick wrote:

webpa wrote:

prc1 wrote:
I have an IBM Thinkpad A20m laptop (2628-4UU) that failed last evening
with the same symptoms that literally hundreds of others have reported
over the last few years. Mine had been running fine, but I went to
power it up and, once it got to the Windows desktop it froze. Powered
off, then tried powering on again. Unit comes on when power is
pressed (HD spins up, all lights flash on then go off except for
power, I can hear the CPU fan running). No POST, no boot, black
screen.

I replaced the CMOS battery, reseated everything, yada yada yada. The
thinkpads.com web forums list a possible cause as a failure of one (or
both) chips in the dc-dc power section on the mainboard. These are
the Analog Devices ADP3421JRU and ADP3410KRU ICs. This is supposedly
due to a design flaw. Some people also say to change three MOSFETs
(IRF-7811) as well. Some report success, others don't.

It seems to me that by simply replacing the chips you're not fixing
the problem. SOMETHING caused the chips to fail as there wasn't (to
my knowledge, anyway) a bad run of those chips. Bad capacitors in the
circuit, maybe? Bad resistors, diodes ...? People ARE apparently
fixing the boards, as dealers will sell you refurbished ones or will
fix your broken unit.

So, what's the secret? Which components are routinely replaced during
the course of one of these repair jobs?
** To respond, remove the crap from my addy... **

Never heard of this myself (have 2 thinkpads...older than yours,
though). Symptoms sound like memory failure. How much installed? If one
stick, remove it and see if you get a POST screen...If 2 sticks, try
removing one and then the other. Sony had a problem with cold solder
joints in the RAM sockets. Maybe they weren't the only ones.

Being another victim of this problem - an A21m to be exact - I can
definitely say it's not a memory issue. It's a mainboard component
failure. The speculation seems to surround component failure in the
power management circuits on the main board. It's also reported a lot on
the T20 series as well. When it happens the system won't even get to a
POST - how could it be a memory failure? Hit the power switch - all five
status LEDs light, then they all go out except for the power on status
LED. Any maybe you hear the CD ROM drive spin up for two seconds. That's
it... You don't even get a screen display, or anything else. Keep trying
that and if you are lucky you will get to a POST. And then if you are
really lucky you might get into the BIOS long enough to disable all
power management options - before if locks up hard. That will help
alleviate the symptoms somewhat. You might get the thing to power on
more consistently. But not enough to prevent the system from locking up
hard within 5 minutes.

It went to an authorized IBM repair center. They tested the RAM and
everything else. All they had to say was "main board failure." And IBM
wanted $999.00 to replace the main board on a computer I paid $799.00
for.

I thought ThinkPads were rock solid. But after this experience... If you
google "dead IBM thinkpad", well, see what pops up.

Now I have to figure out exactly what main board I need for this thing.
The part number listed at IBM's web site doesn't match the unit I have
regarding the on board video system...

Rick
** To respond, remove the crap from my addy... **

I have a few old t20s with similar issues:
Turn off the thinkpad, take out the battery, unplug the power.
Then press the power button for about 90 seconds.
Sometimes it'll work again right away, sometimes you have to let it
sit overnight (unplugged and w/o battery).
Not sure why it works
cb



On Jan 18, 8:27 pm, prc1 wrote:
I have an IBM Thinkpad A20m laptop (2628-4UU) that failed last evening
with the same symptoms that literally hundreds of others have reported
over the last few years. Mine had been running fine, but I went to
power it up and, once it got to the Windows desktop it froze. Powered
off, then tried powering on again. Unit comes on when power is
pressed (HD spins up, all lights flash on then go off except for
power, I can hear the CPU fan running). No POST, no boot, black
screen.

I replaced the CMOS battery, reseated everything, yada yada yada. The
thinkpads.com web forums list a possible cause as a failure of one (or
both) chips in the dc-dc power section on the mainboard. These are
the Analog Devices ADP3421JRU and ADP3410KRU ICs. This is supposedly
due to a design flaw. Some people also say to change three MOSFETs
(IRF-7811) as well. Some report success, others don't.

It seems to me that by simply replacing the chips you're not fixing
the problem. SOMETHING caused the chips to fail as there wasn't (to
my knowledge, anyway) a bad run of those chips. Bad capacitors in the
circuit, maybe? Bad resistors, diodes ...? People ARE apparently
fixing the boards, as dealers will sell you refurbished ones or will
fix your broken unit.

So, what's the secret? Which components are routinely replaced during
the course of one of these repair jobs?
** To respond, remove the crap from my addy... **