Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF

**jason123** · 09-16-2019, 04:42 PM

Hi folks,
I see many having issues with the U3011 monitor display (Westinghouse guts?)

I have one that would work if I unplug power from wall every once in a while. Was like that for about 3 months - Now, it doesn't turn on at all (front LEDs), but no backlight or other signs of life.

I replaced the Power Supply PS-2201-3-HF board and that took care of the problem.

I'm trying to repair the PS-2201-3-HF board. It has 2 connectors sets (top and bottom)
Bottom set seems to be just 24V and GND with ENA, ADJ, and HDCR

Top Connector, P802, is identical, but P803 has 5, GND, 24_EN

I buttoned up the Monitor so I'm troubleshooting this board on my workbench. To turn all the supplies on, I'm assuming I tie 24_EN to 5V (with a small resistor)?

Do I have to do anything with the ENA and HDCR pins??

Any common failures that anyone can share on this board?
Thanks

**jason123** · 09-17-2019, 09:17 AM

Looks like 24_EN on P803 is not connected to anything. So I'm guessing the 24 V comes on when the "ENA" is tied high.. So I shorted it to +5V (which does come on), but the 24 V never comes up. Voltage across large Cap doesn't change - 164 V DC. Is this a PFC circuit issue? Looks like this uses the Fairchild FAN7529B. Schematic anyone?
Thanks

**jason123** · 09-17-2019, 02:30 PM

Ok, update (to myself

) ENA is simply pass through - maybe to turn on the inverter power? I tied 24_EN to 5V, and now the PFC is working and voltage on large cap is 384 VDC. However the 24 V only comes up to 5.2 V.. and gradually drops to 3 and continues to drop. Does the 24V require a load on it?

**jason123** · 09-18-2019, 09:04 AM

I'm not seeing a controller between the 5V to the 24V. Simply a transformer, some diodes and resistors and caps. Is that possible? are they modulating the 5V and transformer turn ratio sufficient to generate 24V then filter? is that it?

**captainKKK** · 09-18-2019, 11:02 AM

Did you check that white fuse in your picture? close to R107.

**jason123** · 09-18-2019, 04:17 PM

That is labeled C107 - I know it's a bad photo. I didn't.. I will shortly and let you know. Seems that the PFC circuit is working - Large Cap voltage goes from 164 to 384 VDC.

**jason123** · 09-19-2019, 11:19 AM

Cap C107 checks out.

**captainKKK** · 09-19-2019, 09:17 PM

What are the voltages on P802 and 803 when it's turned on?

**jason123** · 09-20-2019, 07:47 AM

Hi captainKKK... I found a couple of bad solder joints (actually arching as I move the board) so touched those up, and now 24V comes up to 24.67 V.. However, there is a chatter or relay sound (though I can't find a relay on the whole board)- Audio recording attached.. Seems shorting 5 V to 24_EN is too strong. When I use larger resistors the chatter goes away, but the rail only reaches 20 or 21 V. Any idea what resistance I should put between 5 and 24_EN?
Thanks

**jason123** · 10-09-2019, 06:56 AM

Any help here is appreciated folks.. I'm still having the "Clicking noise" coming out of the transformer??? I replaced the parallel Cap on the primary, and that didn't fix the issue. I'm thinking maybe internal arching? However I can't find a replacement transformer. Can anyone confirm that this indeed could be coming from transformer?

**Topcat** · 10-15-2019, 09:23 PM

Sounds like it to me. I think I have a spare power supply for one of these in the attic, I have one with a broken panel that I've bilked parts out of.

**jason123** · 11-04-2019, 11:07 AM

Quote:

Originally Posted by Topcat

Sounds like it to me. I think I have a spare power supply for one of these in the attic, I have one with a broken panel that I've bilked parts out of.

Hi,
thanks for the post.. would love to get my hands on a supply. I can't find a replacement transformer for this board. I search all over the internet and no one seems to carry that part number

**Topcat** · 11-04-2019, 09:45 PM

Quote:

Originally Posted by jason123

Hi,
thanks for the post.. would love to get my hands on a supply. I can't find a replacement transformer for this board. I search all over the internet and no one seems to carry that part number

I'll poke around tomorrow and see if I can locate it.

**Topcat** · 11-05-2019, 02:39 PM

Quote:

Originally Posted by jason123

Hi,
thanks for the post.. would love to get my hands on a supply. I can't find a replacement transformer for this board. I search all over the internet and no one seems to carry that part number

You're in luck, I found 2 of them. Shoot me a PM if you want one.

09-17-2019, 02:30 PM	#3
jason123 Badcaps Veteran Join Date: Oct 2015 City & State: Reno, Nevada My Country: USA I'm a: Knowledge Seeker Posts: 435	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF Ok, update (to myself ) ENA is simply pass through - maybe to turn on the inverter power? I tied 24_EN to 5V, and now the PFC is working and voltage on large cap is 384 VDC. However the 24 V only comes up to 5.2 V.. and gradually drops to 3 and continues to drop. Does the 24V require a load on it?

09-18-2019, 09:04 AM	#4
jason123 Badcaps Veteran Join Date: Oct 2015 City & State: Reno, Nevada My Country: USA I'm a: Knowledge Seeker Posts: 435	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF I'm not seeing a controller between the 5V to the 24V. Simply a transformer, some diodes and resistors and caps. Is that possible? are they modulating the 5V and transformer turn ratio sufficient to generate 24V then filter? is that it?

09-18-2019, 11:02 AM	#5
captainKKK Senior Member Join Date: Sep 2018 City & State: Katy, Texas My Country: United States Line Voltage: Low I'm a: Knowledge Seeker Posts: 146	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF Did you check that white fuse in your picture? close to R107. Last edited by captainKKK; 09-18-2019 at 11:04 AM..

09-18-2019, 04:17 PM	#6
jason123 Badcaps Veteran Join Date: Oct 2015 City & State: Reno, Nevada My Country: USA I'm a: Knowledge Seeker Posts: 435	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF That is labeled C107 - I know it's a bad photo. I didn't.. I will shortly and let you know. Seems that the PFC circuit is working - Large Cap voltage goes from 164 to 384 VDC.

09-19-2019, 11:19 AM	#7
jason123 Badcaps Veteran Join Date: Oct 2015 City & State: Reno, Nevada My Country: USA I'm a: Knowledge Seeker Posts: 435	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF Cap C107 checks out.

09-19-2019, 09:17 PM	#8
captainKKK Senior Member Join Date: Sep 2018 City & State: Katy, Texas My Country: United States Line Voltage: Low I'm a: Knowledge Seeker Posts: 146	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF What are the voltages on P802 and 803 when it's turned on?

10-09-2019, 06:56 AM	#10
jason123 Badcaps Veteran Join Date: Oct 2015 City & State: Reno, Nevada My Country: USA I'm a: Knowledge Seeker Posts: 435	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF Any help here is appreciated folks.. I'm still having the "Clicking noise" coming out of the transformer??? I replaced the parallel Cap on the primary, and that didn't fix the issue. I'm thinking maybe internal arching? However I can't find a replacement transformer. Can anyone confirm that this indeed could be coming from transformer?

10-15-2019, 09:23 PM	#11
Topcat The Boss Stooge Join Date: Oct 2003 City & State: Salem, MO My Country: United States Line Voltage: 240V @ 60Hz I'm a: Professional Tech Posts: 12,627	Re: Dell U3011 - Troubleshooting the Power Supply board PS-2201-3-HF Sounds like it to me. I think I have a spare power supply for one of these in the attic, I have one with a broken panel that I've bilked parts out of. __________________ <--- Badcaps.net Founder & Owner Badcaps.net Services: Premade Capacitor Kits Badcaps.net Capacitor Master List Motherboard Repair Services If you've come here in search of replacement capacitors or repair services, please use the links above. ---------------------------------------------- Badcaps.net Forum Members Folding Team http://folding.stanford.edu/ Team : 49813 Join in!! Team Stats

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