HP EN623AA - static /blocky white areas

[torin3]

I got this as a non-working monitor. Took it apart, didn't see any obvious damage, so I resoldered the transformer connections, and anything that looked like it might be a bad joint.

Put it back together, and it seemed to work. When the person who owned it got it back, they reported it shut off when they touched the monitor.

I got it back and took it apart again, and saw that the cable between the logic board and the panel was a little loose. I taped it back down with fresh tape and put it back together. Tapped and shook the case a bit and it seemed fine.

However, after letting it sit for about 10 minutes, it started flickering and having static, white areas. Kind of blocky.

Any suggestions on what to look for? I'll be pulling apart the monitor again tomorrow but it is probably too late tonight. I'll take pics of the board then.

Also, I have a short (10 seconds or so) .mov video file of how it is behaving. If anybody thinks it will help, I'll post a link to it.

[Wrog]

Re: HP EN623AA - static /blocky white areas

Looks like a loose LVDS cable to me (the one you've already taped down between the logic board and panel -- did you check both sides?), but it might also be a panel going bad (bonded connectors, not permanently repairable).

Definitely post pics of the power/logic cards when you can, maybe something can be spotted that looks out of place.

[torin3]

Re: HP EN623AA - static /blocky white areas

Looks like a loose LVDS cable to me (the one you've already taped down between the logic board and panel -- did you check both sides?), but it might also be a panel going bad (bonded connectors, not permanently repairable).

Definitely post pics of the power/logic cards when you can, maybe something can be spotted that looks out of place.

Yep, checked both sides.

Oh, and logic and inverter are on the same pcb.

[jetadm123]

Re: HP EN623AA - static /blocky white areas

Does it stay that way after the 10 minutes, or does it clear up after a while? Does it still have the original caps? If so, what brand/series? Possible bad caps on the logic board. Check the voltage regulator(s) output on the logic board.

[torin3]

Re: HP EN623AA - static /blocky white areas

Does it stay that way after the 10 minutes, or does it clear up after a while? Does it still have the original caps? If so, what brand/series? Possible bad caps on the logic board. Check the voltage regulator(s) output on the logic board.

I let it run for about 4-5 minutes and no improvement. Turning it off for about 5 minutes, and back on and it is fine for another 10 minutes before the static returns.

I didn't recap the board, so it is still all the original caps.

Ahh...what the heck. I'll pull it apart now and take pictures.

Edit: Here they are.

[retiredcaps]

Re: HP EN623AA - static /blocky white areas

I'll pull it apart now and take pictures.

Board looks like the Dell E177FPf board at

https://www.badcaps.net/forum/showthread.php?t=12344

[jetadm123]

Re: HP EN623AA - static /blocky white areas

Nice photos! Interesting board with everything on one board. What brand/series caps are they? In the photo, I circled what I believe are the voltage regulators. What are their part numbers? Oh yeah, get some sleep and do this tomorrow.

[torin3]

Re: HP EN623AA - static /blocky white areas

Nice photos! Interesting board with everything on one board. What brand/series caps are they? In the photo, I circled what I believe are the voltage regulators. What are their part numbers? Oh yeah, get some sleep and do this tomorrow.

They appear to all be Su'scon SG series caps.

One of the voltage regulators (the larger one) is a 1117 (LD1117AL 33AGFSL06) part number. And I know the 33 inidicates a 3.3V. The other one is (logo AC) 6A2L 17-18L

Edit - Here are the caps:

1 1000uf - 25V 13mm
2 1000uf - 10V 10mm
3 680uf - 16V 10mm
3 470uf - 25V 10mm
1 470uf - 10v 8mm
3 100uf - 16v 5mm
6 47uf - 15v 5mm
1 10uf - 50v 5mm

And it looks like the board was designed for larger cans on most of the caps based on print size and wider lead hole spacing. Looks like the 8mm cap location can fit a 10mm cap. And most of the 5mm caps can fit 8mm caps.

Plenty of height.

So, keeping in the Panasonic FM / FC range, as long as the uf - volts - 105°C temp specs are kept the same, I'd be ok with going with the larger can sizes if available?

I do have some 680uf and I think some 100uf caps on hand. I'll swap those out now.

[torin3]

Re: HP EN623AA - static /blocky white areas

The 680uf -25v caps I have are Nichicon HEs. Good enough?

I also have a UCC KZE for 1000uf - 25V cap. Looks pretty close to the Panasonics from the data sheets.

Edit: Oh, and the white glue in the pics? Pops right off without leaving residue. Nice!

[jetadm123]

Re: HP EN623AA - static /blocky white areas

They appear to all be Su'scon SG series caps.

One of the voltage regulators (the larger one) is a 1117 (LD1117AL 33AGFSL06) part number. And I know the 33 inidicates a 3.3V. The other one is (logo AC) 6A2L 17-18L

Edit - Here are the caps:

1 1000uf - 25V 13mm
2 1000uf - 10V 10mm
3 680uf - 16V 10mm
3 470uf - 25V 10mm
1 470uf - 10v 8mm
3 100uf - 16v 5mm
6 47uf - 15v 5mm
1 10uf - 50v 5mm

And it looks like the board was designed for larger cans on most of the caps based on print size and wider lead hole spacing. Looks like the 8mm cap location can fit a 10mm cap. And most of the 5mm caps can fit 8mm caps.

Plenty of height.

So, keeping in the Panasonic FM / FC range, as long as the uf - volts - 105°C temp specs are kept the same, I'd be ok with going with the larger can sizes if available?

I do have some 680uf and I think some 100uf caps on hand. I'll swap those out now.

The second component, 6A2L 17-18L, I believe is also a regulator. A 1117-18 to be exact, or 1.8V. It would be interesting to take some voltage readings of these devices before and after the "event" just to see if there's any major difference. Other than that, I think you read my mind as to start replacing the caps. They are original and I'm guessing this monitor is 7-8 years old?

[torin3]

Re: HP EN623AA - static /blocky white areas

The second component, 6A2L 17-18L, I believe is also a regulator. A 1117-18to be exact, or 1.8V. It would be interesting to take some voltage readings of these devices before and after the "event" just to see if there's any major difference. Other than that, I think you read my mind as to start replacing the caps. They are original and I'm guessing this monitor is 7-8 years old?

At least 5 years old or older is my guess. Nicely maintained. Wasn't dusty at all, and no signs of heat damage on the board.

[jetadm123]

Re: HP EN623AA - static /blocky white areas

The 680uf -25v caps I have are Nichicon HEs. Good enough?

I also have a UCC KZE for 1000uf - 25V cap. Looks pretty close to the Panasonics from the data sheets.

Edit: Oh, and the white glue in the pics? Pops right off without leaving residue. Nice!

HE and KZE should work fine.

[torin3]

Re: HP EN623AA - static /blocky white areas

Finally got all the caps in and replaced the old with new.

Still has the same problem. Takes about 1/2 an hour to happen.

Any suggestions on where else to look?

[jetadm123]

Re: HP EN623AA - static /blocky white areas

Finally got all the caps in and replaced the old with new.

Still has the same problem. Takes about 1/2 an hour to happen.

Any suggestions on where else to look?

1) Sounds like it might be a thermal problem. Try heating up parts of the board with a blow dryer to see if you can accelerate the problem.

2) Once the the display goes bad, measure the input and output voltages of the 1.8 and 3.3 voltage regulators.

[torin3]

Re: HP EN623AA - static /blocky white areas

1) Sounds like it might be a thermal problem. Try heating up parts of the board with a blow dryer to see if you can accelerate the problem.

2) Once the the display goes bad, measure the input and output voltages of the 1.8 and 3.3 voltage regulators.

Taking the readings is going to be hard with the way the board is mounted.

Can I solder some wires onto the regulator leads and use those to take my readings?

[jetadm123]

Re: HP EN623AA - static /blocky white areas

Taking the readings is going to be hard with the way the board is mounted.

Can I solder some wires onto the regulator leads and use those to take my readings?

Yes, if that's the only way.

[torin3]

Re: HP EN623AA - static /blocky white areas

Yes, if that's the only way.

Ok, I'm finally going to have time to do this today. Should have the numbers for you in the next couple of hours.

[torin3]

Re: HP EN623AA - static /blocky white areas

Ok, I'm finally going to have time to do this today. Should have the numbers for you in the next couple of hours.

Well, the 3.3V one when I started out was a rock steady 3.30V. When it started doing its weird video thing I read it as 3.33VDC it was gradually climbing. When it got to 3.38VDC I took the probes off, waited a few seconds and then checked again and got 3.39VDC.

I went ahead and turned it off at that point.

Should I leave it on longer and see when it stops?

Should I just switch to the other voltage regulator now?

[retiredcaps]

Re: HP EN623AA - static /blocky white areas

Should I leave it on longer and see when it stops?

Should I just switch to the other voltage regulator now?

If I understand PlainBill correctly, it is better for a voltage regulator to fail low than to fail high. If it fails high, like what you are seeing, it can damage components with too much voltage.

I think you should swap it.

[torin3]

Re: HP EN623AA - static /blocky white areas

If I understand PlainBill correctly, it is better for a voltage regulator to fail low than to fail high. If it fails high, like what you are seeing, it can damage components with too much voltage.

I think you should swap it.

Sounds like a plan.

Would this be a good replacement?

http://search.digikey.com/scripts/Dk...=497-3455-1-ND