Acer 5552G, no lights, nothing. Need schematic, and some luck :(

[inflex]

Client bought in an Acer 5552G, nothing showing, no power-good LED, nothing at all.

Voltages are good at the connector on the mainboard and a couple of the nearby components. Beyond that I'm probing in the dark.

Anyone got a schem for the 5552G series Acer?

[diif]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

This ?

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

Thanks for that Diif. Now comes the hard bit... fixing it.

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

Okay, seems my earlier diagnosis was slightly wrong; it will power up if I put a charged battery on to it. That gives me hope ( since now I can just focus on the ACIN side )

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

UPDATE #2:

If you have both AC and battery plugged in it will NOT power up
If you have only AC plugged in it will NOT power up
If you have only a charged battery plugged in ( no AC ) it will start
If you plug the AC in after it is started, it will keep running and charge the battery.
If you remove the battery with the AC still plugged in it will keep running.

If you connect the AC power while it is off, then connect the battery, it will not charge.

Seems to me that something is wrong perhaps with the ACIN sense?

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

UPDATE #3:

Not sure if the problem is changing, or I'm just seeing things differently. Was able to start today with both ACIN and Battery present. Still doesn't start without the battery though.

[dellxps15]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

with only ac in, report voltage on:

pr61
pq14
pq15
pr69 both side of resistor
pr94 both side of resistor
pq22
pq56

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

with only ac in, report voltage on:

pr61
pq14
pq15
pr69 both side of resistor
pr94 both side of resistor
pq22
pq56

PR61: 15.1V, 15.1V
PQ14: 1~4 18.7V, 5~8 19.2V
PQ15: 1~4 18.7V, 5~8 15.4V
PQ22: 0.28V, 0V, 12.8V
PQ56: 0.28V, 0V, 18.4V


(PQ22 & 56 assuming SOT23/323 packaging pinout as pictured )

[p1muserfan]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

PR61: 0V, 15.1V
PQ14: 1~4 18.7V, 5~8 19.2V
PQ15: 1~4 18.7V, 5~8 8.6V
PQ22: 0.28V, 0V, 12.8V
PQ56: 0.28V, -0.65V, 0.025V

Couldn't locate PR69 or 94 yet. Still searching.

(PQ22 & 56 assuming SOT23/323 packaging pinout as pictured )

PR69 and 94 are both located on the P2 "line" which is between PQ14 and 15. When searching for any component in a schematic with adobe reader, go to the toolbar upper left---edit---find. Type in what you're looking for, hit next, if it's found it will be highlighted for you. Works like a charm.

[dellxps15]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

pr61 show 0v and 15volt other side ? umh looks like there must be some problem here....

try redo the solder both side.

remember only with psu and without battery.
edit:

also PQ15: 1~4 18.7V, 5~8 8.6V

pin 4 is 15volt ?

check those 2 resistor, trace them following the schematic.
pr94 pr69. i think problem is there.
if you can make a good picture of that zone (pr61 pq15)

to trace pr69 pr94 trace pin 4 of pq15. to enable that mosfet pin 4 must be low.

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

Sorry Dellxps15, I went back and edited, I think I had a bad ground when I was measuring some of them ( should use the alligator clips! )

I'll take a photo of the respective areas.

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

Here's a couple of images. Excuse the slightly wonky PQ14 and messy PQ15. I replaced them as "matter of standard habit" and instead of using paste+hotair reflow I got lazy and hand-soldered.

[dellxps15]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

measure voltage in both side of each resistor pr69 pr94 as marked in picture. we cant say with one is pr69 and pr94. u have to desolder and measure with capacimeter, but firse see if they are ok (think one is dead....)

edit: the one upper near pq56 should be pr69 and the one down near caps 0603 should be pr94.

edit: see now your edit. report pu5 voltage.
edit3: report also voltage on pu4 pin 6

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

PU5 Vdd (pin1) 0V

Resistors:

[PQ56]

18.7V [ ] 18.4V
18.7V [ ] 18.7V

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

PU4[6] is 15.0V

PU4[5] is 3.27V

[dellxps15]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

voltage on pl3 and pl4 ?

are u measuring with psu only ? rtc battery is ok ?

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

I think I may have found something, purely by accident... look at the 1206 ceramic between PQ5 and PQ7, looks like it's had a bad day.

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

are u measuring with psu only ? rtc battery is ok ?

PSU only. RTC reads 2.75V

[dellxps15]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

it should be pc31 in schematic. try resolder it.
report pl3 and pl4 voltage. if 5v and 3.3 volt pc shoult start fine.

[inflex]

Re: Acer 5552G, no lights, nothing. Need schematic, and some luck

!!!BINGO!!! We have a winner.

I don't have any 10uF 1206 25V units on hand (highest I have is 16V), but a quick test with a 2u2 item was able to make the unit start.

I'll order some 25V units tomorrow.