Dead Power Supply(XAD819AR) for Acer AL1706

[IRShifty]

When testing this monitor with the dead board I receive no power what so ever, not even the power LED. If I switch out this board with a stock, working board, of the same model, the rest of the monitor works fine, I have replaced 9 caps. All of the ones listed in the picture except for the 4.7µf. Any suggestions as to what the problem might be?

Caps were replaced with,

1000uF 35V 20% Radial-lead Electrolytic Capacitor Operating temperature: --40 to +85°C - X2

470uF 35V 20% Radial-lead Electrolytic Capacitor Operating temperature: --40 to +85°C - X2

220uF 35V 20% Radial-lead Electrolytic Capacitor Operating temperature: --40 to +85°C - X2

100uF 35V 20% Radial-lead Electrolytic Capacitor Operating temperature: --40 to +85°C - X3

[PlainBill]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I see several possibilities.

1. Don't use CapXon's - they're unreliable.

2. Don't use caps rated for 85°C, use low ESR 105°C caps. I prefer Panasonic FC or FW.

3. I question using caps with radically higher voltage ratings, this makes fitting caps into tight quarters more difficult.

4. Have you checked the input fuse?

5. On some power supplies the small caps (like the 4.7 uF 50 volt) cause problems. They are essential for the regulator chip.

PlainBill

[Toasty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

See attached pic.

Toast

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I see several possibilities.

1. Don't use CapXon's - they're unreliable.

2. Don't use caps rated for 85°C, use low ESR 105°C caps. I prefer Panasonic FC or FW.

3. I question using caps with radically higher voltage ratings, this makes fitting caps into tight quarters more difficult.

4. Have you checked the input fuse?

5. On some power supplies the small caps (like the 4.7 uF 50 volt) cause problems. They are essential for the regulator chip.

PlainBill

1. The originals were CapXon and they were all replaced with RadioShack brand.

2. I don't think RadioShack has any caps rated for 105°C. Would using the lower rated caps cause the problem?

3. I also can only find RadioShack caps in 35v for these µf ratings. Would using the higher voltage cause the problem?

4. I have not checked the input fuse as I am fairly new to all this. Where is the specific fuse located and what shall I look for/use to check it, or test it?

5. RadioShacks 4.7µf capacitors are rated at 35v. Would this change pose a problem if it took the place of the 4.7µf 50v CapXon one?

Thankyou for all the suggestions, any help at all is greatly appreciated.

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

See attached pic.

Toast

I am not familiar with checking fuses on power supply boards, what am I looking for when checking these fuses? Do you know the rating on the cap you suggested I change? What is the reason you are suggesting replacing this cap? The last question is just so I can learn. I will post some pictures of the board in roughly 15min.

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

Triple post, oh man. I don't see an edit button though. Here is an image of the board.

[PlainBill]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

1. The originals were CapXon and they were all replaced with RadioShack brand.

That's like replacing old junk with new junk.

2. I don't think RadioShack has any caps rated for 105°C. Would using the lower rated caps cause the problem?

So don't use Radio Shack parts. The FAQ has information on GOOD brands. Link to thread.

3. I also can only find RadioShack caps in 35v for these µf ratings. Would using the higher voltage cause the problem?

Again, don't use Radio shack. The FAQ also has information on reliable distributors. For example, the caps you need would cost $.50 - $1.00 each from Digikey; shipping would be about $2.00

4. I have not checked the input fuse as I am fairly new to all this. Where is the specific fuse located and what shall I look for/use to check it, or test it?

See Toasty's excellent post. Use a VOM. If you don't have one, a VERY cheap one is available from Harbor Freight Tools for under $3.00

5. RadioShacks 4.7µf capacitors are rated at 35v. Would this change pose a problem if it took the place of the 4.7µf 50v CapXon one?

See response to point 3 above.

Thankyou for all the suggestions, any help at all is greatly appreciated.

You're welcome. And Welcome to Badcaps Forums.

PlainBill

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I have repaired other boards using RadioShack brand, but don't get me wrong, I do understand your point of purchasing elsewhere. I was only trying to avoid waiting times that go along with ordering online.

[Toasty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

You're looking for continuity through the fuse(s). No resistance - zero ohms. Most likely one is blown, that is why no indicator light.

>>Do you know the rating on the cap you suggested I change?<<
No. My psychic abilities can only do so much. Perhaps reading the cap markings would help...?

>>What is the reason you are suggesting replacing this cap? The last question is just so I can learn.<<
The reason for replacing the cap is that all the others where replaced, why not do this one too. Think of it as having a 6 cylinder engine in your car and only changing 5 of the spark plugs on a tune-up. Why does it run rough...?

>>RadioShacks 4.7µf capacitors are rated at 35v. Would this change pose a problem if it took the place of the 4.7µf 50v CapXon one?<<
You can NOT replace a higher voltage cap with a lower voltage cap except in very few instances. You CAN replace a lower voltage cap with a higher voltage cap in most instances.

Toast

[Wizard]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

And others have said, the reason with radio shack capacitors they are rejects or unused capacitors sold from manufacters. And lot of these caps don't have good specifications.

Cheers, Wizard

[PlainBill]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I have repaired other boards using RadioShack brand, but don't get me wrong, I do understand your point of purchasing elsewhere. I was only trying to avoid waiting times that go along with ordering online.

The waiting time is minimal. DigiKey will ship small packages first class mail and priority mail. If you place an order Monday evening it will ship Tuesday and be delivered Thursday or Friday. The speed advantage of buying from Radio Shack must be weighed against getting quality parts with the correct ratings.

The reason for replacing the 4.7 uF cap was simple. That cap is responsible for storing the energy the voltage regulator requires to start. If it is bad the power supply won't start. I got burned on that one myself. I replaced EVERY cap except that one in a Gateway monitor. And it still wouldn't work until I replaced that cap. Others have had the same problem. This week I repaired an Acer monitor which used the same voltage regulator as the Gateway. And you can bet that I replaced that cap, even though the power supply was working.

To mimic the Mastercard commercial:

Cost of Replacement parts: $12.00
Shipping: $6.00
Time to disassemble monitor, troubleshoot, repair, and reassemble: 1 Hour

KNOWING you aren't going to have to open the monitor up again: Priceless.

PlainBill

[PCBONEZ]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

There is nothing wrong with Radio Shack capacitors except that they aren't rated for this kind of application.

Rack Shack carries Xicon 85C caps for the most which are a good brand but they are General Purpose caps.

- Low ESR and high Ripple ratings are required here.

General Purpose caps aren't going to live very long and just might take some other parts out with them when they go.

I don't see how having to fix it again later is a savings in time.
.

[xtraelectronics]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I agree with the message about rat shack caps... I bought a large number of them from a liquidation place here when they went to "The Source" in Canada. Testing them with an ESR meter, over half were no good.

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I am waiting on getting a VOM for checking the fuses, either later today or tomorrow. I don't know if I can get the rest of the caps I need locally. I don't have a problem ordering them online. Except for the fact I don't know a lot about them and the order form is pretty complicated coming from my view. Can someone tell me how to properly fill out the inventory form on digikey to get what I need to purchase here.

PS. The black/silver cap that I was told to replace as well is a 47µf 50v. The only reason I asked if you knew was because its a bitch to see without removing it.

[PlainBill]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I am waiting on getting a VOM for checking the fuses, either later today or tomorrow. I don't know if I can get the rest of the caps I need locally. I don't have a problem ordering them online. Except for the fact I don't know a lot about them and the order form is pretty complicated coming from my view. Can someone tell me how to properly fill out the inventory form on digikey to get what I need to purchase here.

PS. The black/silver cap that I was told to replace as well is a 47µf 50v. The only reason I asked if you knew was because its a bitch to see without removing it.

That confirms it. That's the $@%#^#! that drove me nuts for a week!!
Using DigiKey CAN be daunting. This works for me; others will have ways that work better for them.

From the DidiKey home page, click on 'Go' next to the Search box. This takes you to a list of categories. Scroll down to Capacitors, then click on Electrolytic - Aluminum. On the filters page select the Capacitance, Through Hole, Radial, the Voltage (extreme right hand column), and check the In Stock box, then click on 'Apply Filters'. This should take you to a list of matching parts. From that list concentrate on ones with a 105ºC rating, that are the same size as the originals (or will fit), and the greatest life expectancy. Make sure they will sell onsies and twosies. Unless you are repairing a LOT of monitors, a box of 5000 is overkill.

Reviewing, you need

1ea 47uF 50V DigiKey P10321-ND @ $.28 ext $.28

1 ea 100uF 10V DigiKey P10219-ND @ $.30 ext $.30

2 ea 100uF 25V DigiKey P10269-ND @ $.23 ext $.56

2 ea 220uF 25V DigiKey P10271-ND @ $.38 ext $.76

2 ea 470uF 25V DigiKey P10275-ND @ $.57 ext $1.14

2 ea 1000uF 10V DigiKey P10225-ND @ $.59 ext $1.16

That totals to $4.20 plus about $2.00 for shipping. BUT before you order, enter each of these part numbers and make sure they will fit!! Height is important; just ask PlainBill what happened on his Mouser order.

As far as the VOM, if you are willing to spend a few bucks more, Harbor Freight Tools has an inexpensive DVM (37772-2VGA ) for about $25 that includes some very nice features.

PlainBill

[Toasty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

What were the original cap values and series? One side has the brand name, capacitance and voltage values. The other side has the series letters such as GL or KF then the temperature rating. Report back with all the original info and we can guide you for the order.

>>its a bitch to see without removing it.<<
Welcome to our world.

Toast

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I'm not sure if I still have all the old caps. I might have to go dumpster diving =X. Is it likely that they are the same series caps throughout the different µf ratings? If so the 220's are "CapXon 220µf 25V GF105°C P602 VENT."

EDIT: After a quick dumpster dive, "1000µf 10V GF105°C P602 VENT," "470µf 25V GF105°C P544 VENT," were found.

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

After a slightly longer dumpster dive. "100µf 25v GF105°C P602 VENT" was also found. No luck of the 100µf 10v.

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I looked for an LED light to use while trying to read the info from the caps on the stock board, but it seems I don't have one. So I used a laser and that worked fine. Info on the 100µf 10v is "100µf 10V GF105°C P602 VENT" as expected.

PS. The edit timer should really be bumped to 30min.

[IRShifty]

Re: Dead Power Supply(XAD819AR) for Acer AL1706

I really do have to apologize for all the multi-posting. Even if you guys are okay with it. It really is not necessary. I just wish the edit timer was longer.

Okay here is a wrap-up with measurements.

1x - "4.7µf 50V GF105°C P602 VENT" (0.1875"D x 0.4375"H)
1x - "47µf 50V CD81 +105°C U1" (0.25"D x 0.4375"H)
1x - "100µf 10V GF105°C P602 VENT" (0.25"D x 0.4375"H)
2x - "100µf 25v GF105°C P602 VENT" (0.25"D x 0.4375"H)
2x - "220µf 25V GF105°C P602 VENT" (0.3125"D x 0.5"H)
2x - "470µf 25V GF105°C P544 VENT" (0.375"D x 0.625"H)
2x - "1000µf 10V GF105°C P602 VENT" (0.375"D x 0.625"H)