Acer AL1916WA No Power

[trwilson70]

This power supply is different than other Acer AL1916's - at least ones I've read about. No power light at any time. I've replaced 8 caps with panasonic fm's. Have 164 volts on big cap. Measured output to logic board - top two wires are 5v, others are 0. Measuring across the other caps.
C809 = 14.57v
C843,C845,C850 = 21.6v
C847,C848 = 5.06v
C902,C903 = 10.84
Is the logic board bad? What can I check next?
PS/Inverter: AW698 VP-930
Thanks

[Dgtech]

Re: Acer AL1916WA No Power

F802 on the upper right hand corner of the board.
U6 and U7 are most likely regulators(on processor board) - check input and output voltages. You can find pinout on datasheet of each. Just post what the markings are on each of the 2 components.

[PlainBill]

Re: Acer AL1916WA No Power

This power supply is different than other Acer AL1916's - at least ones I've read about. No power light at any time. I've replaced 8 caps with panasonic fm's. Have 164 volts on big cap. Measured output to logic board - top two wires are 5v, others are 0. Measuring across the other caps.
C809 = 14.57v
C843,C845,C850 = 21.6v
C847,C848 = 5.06v
C902,C903 = 10.84
Is the logic board bad? What can I check next?
PS/Inverter: AW698 VP-930
Thanks

Check and report the voltage on all pins of U6 and U7 on the logic board. Use the mounting pad in the upper right corner, or the - pad (the one surrounded in white) of unused cap C64 as the ground point. Also, what are the part numbers of U6 and U7?

PlainBill

[budm]

Re: Acer AL1916WA No Power

This may help, Service manuals: http://elektrotanya.com/?q=showresul...oria=&kat2=all

http://s807.photobucket.com/home/budm/allalbums

[trwilson70]

Re: Acer AL1916WA No Power

U6 is APL1084, reading top to bottom I have 5.02v, 3.28v, 0v
U7 is APL1117, reading left to right I have 3.28v, 1.09v, 0v

[retiredcaps]

Re: Acer AL1916WA No Power

Great photos. I found them about 3 or 4 weeks ago and was wondering if you were on this board or not.

I have already learned a lot just from your pictures and descriptions.

This may help, Service manuals: http://elektrotanya.com/?q=showresul...oria=&kat2=all

http://s807.photobucket.com/home/budm/allalbums

[PlainBill]

Re: Acer AL1916WA No Power

U6 is APL1084, reading top to bottom I have 5.02v, 3.28v, 0v
U7 is APL1117, reading left to right I have 3.28v, 1.09v, 0v

The usual voltages for the control chip are 3.3 and 1.25 volts. 3..28 is well within tolerances; but 1.09 is low. We have been seeing some bad APL1117's lately. When they fail high the processor is destroyed. Fortunately this one seems to be failing low. Just for my peace of mind, are there any more characters in the part number of that one?

PlainBill

[EGuevarae]

Re: Acer AL1916WA No Power

This may help, Service manuals: http://elektrotanya.com/?q=showresul...oria=&kat2=all

http://s807.photobucket.com/home/budm/allalbums

Nice.....

[trwilson70]

Re: Acer AL1916WA No Power

Characters below the part number = GJ70618
Where can these be purchased?

[PlainBill]

Re: Acer AL1916WA No Power

Characters below the part number = GJ70618
Where can these be purchased?

If I recall correctly, it's a 'jelly bean' part, made by a number of manufacturers with identical pinout and specs. Check the service manual - often they include a BOM (bill of materials) including manufacturer's part numbers. Note that I have NOT checked the service manual yet, so don't go ordering lots of parts until someone who has their act together confirms that voltage is wrong.

PlainBill

[PlainBill]

Re: Acer AL1916WA No Power

If I recall correctly, it's a 'jelly bean' part, made by a number of manufacturers with identical pinout and specs. Check the service manual - often they include a BOM (bill of materials) including manufacturer's part numbers. Note that I have NOT checked the service manual yet, so don't go ordering lots of parts until someone who has their act together confirms that voltage is wrong.

PlainBill

I took a look at it, and the best information I have is that that IS a 1.8 volt regulator. It's available by STMicroelectronics from Digikey as 497-6868-1-ND LD1117S18CTR for $.79

PlainBill

[trwilson70]

Re: Acer AL1916WA No Power

Thanks PlainBill, I am putting together an order for Digikey so will get a couple. Will report back once I get it.

[trwilson70]

Re: Acer AL1916WA No Power

Whoot! Thanks PlainBill,
Placed order Monday P.M. - ordered arrived today - Digikey is awesome. I've not done much SMD work but managed to get voltage regulator removed, new one installed. I tested voltage again and noticed the middle leg only read 1.8 when I pushed down with probe, .5v when I didn't. With this voltage - screen lit up - all white, still no power led. Removed logic board and soldered middle leg while holding down - voltage now reads 1.8v and I have an 'ACER' splash - hooked up VGA - nice picture! Thank you!

[EGuevarae]

Re: Acer AL1916WA No Power

Whoot! Thanks PlainBill,
Placed order Monday P.M. - ordered arrived today - Digikey is awesome. I've not done much SMD work but managed to get voltage regulator removed, new one installed. I tested voltage again and noticed the middle leg only read 1.8 when I pushed down with probe, .5v when I didn't. With this voltage - screen lit up - all white, still no power led. Removed logic board and soldered middle leg while holding down - voltage now reads 1.8v and I have an 'ACER' splash - hooked up VGA - nice picture! Thank you!

Do you have a picture of the offending component installed?

[trwilson70]

Re: Acer AL1916WA No Power

I thought of taking a photo prior to reassembling but failed to do so. I forgot to mention that I also replace the larger cap near the regulator as a precaution. I just bought a blue esr meter - it showed that it was near the upper limits for that size cap.