HP ZR2740W - Flickered once and then wouldn't turn on

[darkdead]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

hello i just order a faulty HP ZR2740W, when it arrive i can help trobleshotining.
But soo far reading people there are to comon fail on the screeen led blacklight issues and scaler issues.
Tcon board and panel itslef i dont se issues at all.
one question is, the led strips operate voltage are 30v or 60v? xxx ma may be 250ma? this point is important becuse for test whit fake load instead the screen led strips becuse if one led open or shorted made the led protecting shut donw the monitor also can tricked on the led pwm chip but whit risk burn the led mosfets if led strips got a ground short.
whit the led voltage may be can tested whit whit led outside 30v 90ma led driver whitout risk burn the leds.
BTW any pcb numbers for find the monitor datasheets?
Soory for my english no my natural languaje but got enoght skill for fix it and love help others on the same boat.

[Teeva]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Not sure, I can't see anything on that page which matches your monitor or PSU - can you?

Probably best to start with comparing voltages on the PSUs, check all the controller ICs etc on bad PSU are they all getting voltage - are they getting the same voltage as the working PSU? That sort of thing

Check on Q808 to see if you get any 5v.

[Agent24]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

I found this, if it helps

http://www.eserviceinfo.com/index.ph...atung+pwb-1421

Not sure, I can't see anything on that page which matches your monitor or PSU - can you?

Probably best to start with comparing voltages on the PSUs, check all the controller ICs etc on bad PSU are they all getting voltage - are they getting the same voltage as the working PSU? That sort of thing

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

The power at the main cap, that's probably AC voltage. 120 vac comes in and drops down to 60vac at transformers.

If you can find the new PSU for $30, I think that's that the best way to go. I tried to find one on ebay but couldn't find any at the time.

This is what I found, but last night when I tried to check out it jist showed a blank page. I'll try again or call

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Ah, I see, Q808 is switched with the UCC24610 to provide rectification for the 5v rail instead of using a plain diode. No wonder I couldn't see one!

I found this, if it helps


http://www.eserviceinfo.com/index.ph...atung+pwb-1421

[Agent24]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Ah, I see, Q808 is switched with the UCC24610 to provide rectification for the 5v rail instead of using a plain diode. No wonder I couldn't see one!

[Teeva]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Yes, I am running with the original logic board.

The only thing that has changed is the PSU, the metal chassis that supports the PSU and Logic board, and I may have switched the PSU>Logic Board power cable and the Logic Board>LCD cables. I also added a cut-up ziplock bag between the back of the LCD and the PSU/Logic assembly, but I don't think it was doing anything as it was free to slide around. I figured it couldn't hurt though.

The original PSU was able to get voltage to the large main Caps, but I had zero output to the logic board.

Looking back at my notes, it looks like secondary PSU+Logic Board and the original LCD is the combo that fried the transistor. Very odd, that leads me to believe I accidentally did something wrong?
Then again, the fact that I easily got the current setup up and running first try and rather quickly makes me question whether I really did make a mistake or not.

Either way, I'm now likely going to try replacing that transistor and then seeing if I can get a working secondary going again from the leftover parts. I found that for $30 you can buy a new PSU for it, so I'm going to keep that in mind. I think it would be cooler to be able to fix it on my own, but $30 is hard to argue with.

The power at the main cap, that's probably AC voltage. 120 vac comes in and drops down to 60vac at transformers.

If you can find the new PSU for $30, I think that's that the best way to go. I tried to find one on ebay but couldn't find any at the time.

[Teeva]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Here is the list of the parts(ics) that I got when I tried to repair mine:

-FDS8842NZ(AP9468G) .... I802 .... MOSFET N-CH 40V 14.9A 8SOIC.... DIGIKEY PN: FDS8842NZCT-ND

-UCC28610D ..... I804..... IC CTLR PWM GREEN MODE 8SOIN.... DIGIKEY PN: 296-34756-5-ND

-UCC28051DR .... I801.... IC PFC CTRLR TRANSITION 8SOIC.... DIGIKEY:296-27158-1-ND

-UCC25600DR ....I811.... IC REG CTRLR ISO PWM VM 8SOIC... DIGKEY:296-38315-2-ND

-ATP404-TL-H ...Q808... .. MOSFET N-CH 60V 95A ATPAK ....DIGIKEY:869-1087-1-ND

-STP13NM60N(13NM60N) ...... MOSFET N-CH 600V 11A TO-220.... DIGKEY:497-8787-5-DN

-UCC24610DR .... I805 .... IC SECONDARY-SIDE CTRLR 8SOIC.... DIGIKEY:296-27855-1-ND

-TL103WIDR(Z103WA) .... I810.... IC OPAMP GP 900KHZ 8SOIC...... DIGIKEY:296-18861-2-ND

-LM358DR ..... I815 .... IC OPAMP GP 700KHZ 8SOIC...... DIGIKEY:296-1014-1-ND

[Agent24]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

It shouldn't be too hard, if you have the working PSU. You can compare voltages and things.

Last time I had a totally dead monitor it was a shorted rectifier on the 5v rail. I tried to find the 5v rail rectifier on this PSU but can't see anything. It seems to go straight back to the transformer output. There is only an obvious rectifier for the 12v rail. In any case, you could compare the resistance from 5v rail to GND on the PSU, see if it looks lower or shorted on the bad PSU for a start.

Edit: Brainfail - check the diode on 12v too for shorts, since it's on the same transformer, if it's bad it would probably cause problems too. D604 might as well test as well.

Can you give part numbers for the ICs on the PSU? The little 8-pin SMD ones, I804, I805 and I802

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Yes, I am running with the original logic board.

The only thing that has changed is the PSU, the metal chassis that supports the PSU and Logic board, and I may have switched the PSU>Logic Board power cable and the Logic Board>LCD cables. I also added a cut-up ziplock bag between the back of the LCD and the PSU/Logic assembly, but I don't think it was doing anything as it was free to slide around. I figured it couldn't hurt though.

The original PSU was able to get voltage to the large main Caps, but I had zero output to the logic board.

Looking back at my notes, it looks like secondary PSU+Logic Board and the original LCD is the combo that fried the transistor. Very odd, that leads me to believe I accidentally did something wrong?
Then again, the fact that I easily got the current setup up and running first try and rather quickly makes me question whether I really did make a mistake or not.

Either way, I'm now likely going to try replacing that transistor and then seeing if I can get a working secondary going again from the leftover parts. I found that for $30 you can buy a new PSU for it, so I'm going to keep that in mind. I think it would be cooler to be able to fix it on my own, but $30 is hard to argue with.

[Agent24]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

So you are currently running with the original logic board etc and the other PSU?

I wonder if the original PSU was faulty and blew that transistor on the other logic board?

But you say the bad PSU has no voltage output at all?

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Well, I've got my main up and running again... but it took a donor PWB-1421 from my second zr2740w.

So, obviously then the issue with my original monitor is the power supply.

[Teeva]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

I am not in front of the board right now, but would I be able to visually trace the 5V line from P803 backwards, testing components on the way, to hopefully find what ever is blocking 5V from being supplied to P803?

The area that I would get vdc, I remember, was in the area I hightlighted in the pic attached, so I would focus on that area. Please BE CAREFUL when work on the board, especially on high voltage area.

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

If you can locate the 5v source, then, I am sure, you can fix the power board.
If you get the 5v on P803, then power LED will be on but amber. In order to turn LED backlight on, you'll need to connect video cable to PC;otherwise, it won't turn on.

I am not in front of the board right now, but would I be able to visually trace the 5V line from P803 backwards, testing components on the way, to hopefully find what ever is blocking 5V from being supplied to P803?

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Your readings do not make sense to me.
These are in Diode mode testing or DC Voltage testing with the monitor plugged into the outlet?
In testing the original Monitor 1 transistor from the same location:
M.M. Black lead to Base
2nd terminal: 0.000 VDC =This should mean shorted (same reading as shorting two probes together) if you are in diode mode testing
3rd terminal: 0.000 VDC =This should mean shorted (same reading as shorting two probes together) if you are in diode mode testing

M.M. red lead to Base
2nd terminal: 0.000 VDC =This should mean shorted (same reading as shorting two probes together) if you are in diode mode testing
3rd terminal: 0.374 VDC

Using resistance:
M.M. Black lead to Base
2nd terminal: 6.22 M Ohm: But then it show resistance in Mega Ohm here
3rd terminal: 6.27 M Ohm: But then it show resistance in Mega Ohm here

M.M. Red lead to Base
2nd terminal: begins at 80 K Ohm and quickly climbs
3rd terminal: begins at 1.1 M Ohm and quickly climbs

This was with nothing plugged in. I was using Diode test mode on my Multimeter.

Even in Diode test mode, do I need power to the monitor?

Also, when I say I am touching the base, I only determined that by following another tutorial on "determining base through resistance". If looking at the transistor from the top, with the single leg on the top side and dual legs on the bottom side, the base was the top leg.

So it sounds like this transistor is not functioning on both boards, one fried and the other silently died? I will order some replacements, but likely will need to fix what ever blew them to start.

[Teeva]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

If you can locate the 5v source, then, I am sure, you can fix the power board.
If you get the 5v on P803, then power LED will be on but amber. In order to turn LED backlight on, you'll need to connect video cable to PC;otherwise, it won't turn on.

[budm]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Your readings do not make sense to me.
These are in Diode mode testing or DC Voltage testing with the monitor plugged into the outlet?
In testing the original Monitor 1 transistor from the same location:
M.M. Black lead to Base
2nd terminal: 0.000 VDC =This should mean shorted (same reading as shorting two probes together) if you are in diode mode testing
3rd terminal: 0.000 VDC =This should mean shorted (same reading as shorting two probes together) if you are in diode mode testing

M.M. red lead to Base
2nd terminal: 0.000 VDC =This should mean shorted (same reading as shorting two probes together) if you are in diode mode testing
3rd terminal: 0.374 VDC

Using resistance:
M.M. Black lead to Base
2nd terminal: 6.22 M Ohm: But then it show resistance in Mega Ohm here
3rd terminal: 6.27 M Ohm: But then it show resistance in Mega Ohm here

M.M. Red lead to Base
2nd terminal: begins at 80 K Ohm and quickly climbs
3rd terminal: begins at 1.1 M Ohm and quickly climbs

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

D1 is probably a BCW31
http://www.datasheetarchive.com/BCW31-D1-datasheet.html

Thanks!

Do my results make sense and indicate a functioning transistor?

[selldoor]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

D1 is probably a BCW31
http://www.datasheetarchive.com/BCW31-D1-datasheet.html

[fl0w3n]

Re: HP ZR2740W - Flickered once and then wouldn't turn on

Just to double check, I tested the visibly fried transistor on Monitor #2 and it of course shows a short.

In testing the original Monitor 1 transistor from the same location:
M.M. Black lead to Base
2nd terminal: 0.000 VDC
3rd terminal: 0.000 VDC

M.M. red lead to Base
2nd terminal: 0.000 VDC
3rd terminal: 0.374 VDC

Using resistance:
M.M. Black lead to Base
2nd terminal: 6.22 M Ohm
3rd terminal: 6.27 M Ohm

M.M. Red lead to Base
2nd terminal: begins at 80 K Ohm and quickly climbs
3rd terminal: begins at 1.1 M Ohm and quickly climbs


It appears the imprint on top of this transistor reads "D1 T0G".