Anyone Have experience/Schematic w/ Acer Aspire 5532 Motherboard?

[Paul678]

I just want to know before I post some pics.

The board simply does not turn on at all. The 19Volts
is healthy at the input, so there is no short to ground,
but still nothing.

I looked for voltages on the ribbon going to the power
switch board, and there is nothing.

Someone had apparently spilled some sort of
fluid on this one. I got off most of the gunk with
alcohol, but it still does nothing.

I know it's a long shot, but I just wanted to see
if someone had an idea of which components I should
look at first.....

Thanks for reading

[Paul678]

Ok, here are some pics big enough to see component
markers:





I was able to trace the +19V to the 3.3 Ohm resistors,
PR43 and PR40 (to the right edge of large fan opening),
but it appeared to stop at that point.

Again, there were no significant voltages on the ribbon
going to the power/On-Off board, just some 0.4 Volts
here and there, and again, nothing happens when I
press the ON button.

I know it's a long shot, but if someone has any ideas of
where to look next, it would be much appreciated.

[severach]

Measure voltage at the on/off button. One of the pins will change from 3.3v to 0v when the power button is pushed.

[Paul678]

Originally Posted by severach

Measure voltage at the on/off button. One of the pins will change from 3.3v to 0v when the power button is pushed.

There was one pin on at the on/off button that
measured about 0.3 V, so that's probably what
should be +3.3V. I traced it to the motherboard,
but I couldn't find what components it leads to.

Needle in Haystack without a schematic.....

[nucleus]

here is link for schematics.

http://lqv77.com/download/648/

[Paul678]

Originally Posted by nucleus

here is link for schematics.

http://lqv77.com/download/648/

Thanks, that's a huge help, even though it doesn't
exactly match my board, component ID wise, which
shouldn't surprise any of the engineers out there.

But I was missing the +3VALW, which is +3.3V always
on, which is what the on/off switch shorts to ground.

According to the schematic, it's generated by this:

http://www.intersil.com/content/dam/...n64/fn6418.pdf


So I found this IC on my board, and it indeed was
attached to the switch, but it was missing the reference
voltage, which ranges from +5.5 to +25V.

It should have been safe to jumper the +19V
input voltage to this chip, but when I tried it,
the IC started smoking! Damn! The chip
is supposed to be always on!

Oh well, I'm gonna end up parting this laptop
out.....the LCD screen display and housing
is gonna fetch $80 alone!

Thanks for the input anyways.....Remember that
research and curiosity are NEVER in vain!

[nucleus]

try to replace chip first if you have it on some old board. also chek on schematics which are pins for input voltages and if there is volatge that should be. if there is no input V trace it to where it should come from.

[Paul678]

Originally Posted by nucleus

try to replace chip first if you have it on some old board. also chek on schematics which are pins for input voltages and if there is volatge that should be. if there is no input V trace it to where it should come from.

I don't have a hot-air rework station. And I only have one
other old board, and it doesn't have the same chip.

According to the schematic, the input voltage should come
from either the battery or the AC adaptor's +19V, which
makes sense because it's outputting the "always on" voltages.

[mattbrad2]

Paul, the problem all along was the intersil PWM IC. A common problem in this series of Acer. Replace that and you *would* have been fine however now there may be more damage.

[Paul678]

Originally Posted by mattbrad2

Paul, the problem all along was the intersil PWM IC. A common problem in this series of Acer. Replace that and you *would* have been fine however now there may be more damage.

Oh no, another "know-it-all" personality, who doesn't know
what he's talking about!

This had nothing to do with pulse width modulation. Look
at the schematic, and there are "always on" voltages. Both the
+3.3V and the +5V always on weren't there, so the computer
could not be turned on.

[tom66]

PWM often drives a buck converter to generate 3.3V and 5V supplies... (so called always on supplies.)

[Paul678]

Originally Posted by tom66

PWM often drives a buck converter to generate 3.3V and 5V supplies... (so called always on supplies.)

The datasheet says it's a linear regulator for the
fixed +3.3 and +5Volts:

http://www.intersil.com/content/dam/...n64/fn6418.pdf

If this chip is for the "always on" voltages, why wasn't the
+19V at the Vin?

Perhaps because the chip itself had Vin shorted
to ground, and burned out the trace.

[tom66]

No idea - there's a reason I don't work on laptops often.

[mattbrad2]

Originally Posted by Paul678

Oh no, another "know-it-all" personality, who doesn't know
what he's talking about!

This had nothing to do with pulse width modulation. Look
at the schematic, and there are "always on" voltages. Both the
+3.3V and the +5V always on weren't there, so the computer
could not be turned on.

Not quite sure where the attitude is coming from but I'll be sure not to help you out in the future. All I was saying was I've seen this exact problem on this exact series (I've been working on laptops for 20 years) and its always been that intersil IC. It's this IC that is generating your "always on" voltage. Both 5v AND 3.3 come from this little guy. I'm not sure how you're reading that schematic but its pretty clear to me. Anyway.. I won't respond to this thread any longer. Good luck.

[budm]

"The datasheet says it's a linear regulator for the
fixed +3.3 and +5Volts:

http://www.intersil.com/content/dam/...n64/fn6418.pdf

From the Data sheet you provided: page1
"The ISL6237 dual step-down, switch-mode power-supply
(SMPS) controller generates logic-supply voltages in
battery-powered systems. The ISL6237 includes two
pulse-width modulation (PWM) controllers, 5V/3.3V and
1.5V/1.05V. The output of SMPS1 can also be adjusted from
0.7V to 5.5V. The SMPS2 output can be adjusted from 0.5V to
2.5V by setting REFIN2 voltage. This device features a linear
regulator providing 3.3V/5V, or adjustable from 0.7V to 4.5V
output via LDOREFIN. The linear regulator provides up to
100mA output current with automatic linear-regulator
bootstrapping to the BYP input. When in switchover, the LDO
output can source up to 200mA. The ISL6237 includes
on-board power-up sequencing, power-good (POK_) outputs,
digital soft-start, and internal soft-stop output discharge that
prevents negative voltages on shutdown.
Constant on-time PWM control scheme operates without
sense resistors and provides 100ns response to load
transients while maintaining a relatively constant switching
frequency. The unique ultrasonic pulse-skipping mode
maintains the switching frequency above 25kHz, which
eliminates noise in audio applications. Other features include
pulse skipping, which maximizes efficiency in light-load
applications, and fixed-frequency PWM mode, which reduces
RF interference in sensitive applications."

[Paul678]

Originally Posted by mattbrad2

Not quite sure where the attitude is coming from but I'll be sure not to help you out in the future. All I was saying was I've seen this exact problem on this exact series (I've been working on laptops for 20 years) and its always been that intersil IC. It's this IC that is generating your "always on" voltage. Both 5v AND 3.3 come from this little guy. I'm not sure how you're reading that schematic but its pretty clear to me. Anyway.. I won't respond to this thread any longer. Good luck.

Thanks for repeating what I just posted earlier!

Did you even read the schematic?

Page 5 and 33 show how this chip supplies
the +3.3V to the power switch.

And you are wrong about replacing the chip
and I would have been fine, because the +19V
wasn't even present. It should always be present,
if this chip is "always on". So at the least, I would
have had to install a jumper to the +19V. If anything,
the trace may have acted as a fuse, and prevented
the IC from smoking the way it did when I jumpered
it, but the chip was certainly bad.

[Paul678]

Originally Posted by budm

"The datasheet says it's a linear regulator for the
fixed +3.3 and +5Volts:

http://www.intersil.com/content/dam/...n64/fn6418.pdf

From the Data sheet you provided: page1
"The ISL6237 dual step-down, switch-mode power-supply
(SMPS) controller generates logic-supply voltages in
battery-powered systems. The ISL6237 includes two
pulse-width modulation (PWM) controllers, 5V/3.3V and
1.5V/1.05V. The output of SMPS1 can also be adjusted from
0.7V to 5.5V. The SMPS2 output can be adjusted from 0.5V to
2.5V by setting REFIN2 voltage. This device features a linear
regulator providing 3.3V/5V, or adjustable from 0.7V to 4.5V
output via LDOREFIN. The linear regulator provides up to
100mA output current with automatic linear-regulator
bootstrapping to the BYP input. When in switchover, the LDO
output can source up to 200mA. The ISL6237 includes
on-board power-up sequencing, power-good (POK_) outputs,
digital soft-start, and internal soft-stop output discharge that
prevents negative voltages on shutdown.
Constant on-time PWM control scheme operates without
sense resistors and provides 100ns response to load
transients while maintaining a relatively constant switching
frequency. The unique ultrasonic pulse-skipping mode
maintains the switching frequency above 25kHz, which
eliminates noise in audio applications. Other features include
pulse skipping, which maximizes efficiency in light-load
applications, and fixed-frequency PWM mode, which reduces
RF interference in sensitive applications."

From your quote:

"This device features a linear
regulator providing 3.3V/5V, or adjustable from 0.7V to 4.5V
output via LDOREFIN. The linear regulator provides up to
100mA output current with automatic linear-regulator
bootstrapping to the BYP input. "

[budm]

There is only ONE LDO output with very limited current output, it can be set to output 5V or 3.3V.
See page 23 for typical setup for TWO output supplies 3.3V AND 5V for always on power supply.
So look at the board and see if the IC is hooked close to as shown in the app notes.

[Paul678]

Originally Posted by mattbrad2

Paul, the problem all along was the intersil PWM IC. A common problem in this series of Acer. Replace that and you *would* have been fine however now there may be more damage.

You are incorrect.

It turns out there is no B+ anywhere on this board, so this chip was
NOT the problem.

There's a good reason I don't trust people who say they
are 100% sure they know the problem.....

Nevertheless, thanks to Nucleus for the excellent schematic!

Do you really live in this tiny little town?

http://en.wikipedia.org/wiki/Bijelo_Polje

[budm]

So on page 38 of the service manual where the ALWAYS ON 3.3V and 5V which are generated by the TWO SMPS you are not getting B+ at jumper PJ17?

You also do not have VIN on page 38 from the DC input jack PJP1?

Page 40: B+ comes from MOSFET switches PQ7, PQ8 which are turn on (PIN 4 ACDRV will go low when ACDET sees the VIN from AC adapter) when the ACDET PIN 5 of PU4 Power control IC sees VIN.