HP w2007 PTB-1773 - Where to start?

[maverick530]

I have a HP w2007 20" LCD monitor that has died. No lights, no nothing. I suspect the power board since there are no lights at all, but I'm at a loss as to where to start in order to fix it since it passes my visual inspection of the caps. No caps seem bulged and the fuse shows continuity still.

Any ideas?

Attached are pictures of the front and back, and here's some identifying markings:

Back sticker:
0716P
793V8A02810 AG

6832177300P02 PTB-1773 02/06 '07

Front:
E59670

0733-5

6832177300P02
PTB-1773 02/06 '07

Front Sticker:
5073291-6430 AE
7354C403687 30716P


(D809)
MOSPEC
URF1020C
MA6G

(Q803)
KHB
700N65F
728


It looks like a similar model if not the exact same PTB-1773 is also found in HP W1907 monitors? Anyone have success in fixing these? If so, what are common problems?

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

I have a HP w2007 20" LCD monitor that has died. No lights, no nothing. I suspect the power board since there are no lights at all, but I'm at a loss as to where to start in order to fix it since it passes my visual inspection of the caps. No caps seem bulged and the fuse shows continuity still.

Any ideas?

Attached are pictures of the front and back, and here's some identifying markings:

Back sticker:
0716P
793V8A02810 AG

6832177300P02 PTB-1773 02/06 '07

Front:
E59670

0733-5

6832177300P02
PTB-1773 02/06 '07

Front Sticker:
5073291-6430 AE
7354C403687 30716P


(D809)
MOSPEC
URF1020C
MA6G

(Q803)
KHB
700N65F
728


It looks like a similar model if not the exact same PTB-1773 is also found in HP W1907 monitors? Anyone have success in fixing these? If so, what are common problems?

The first step would be to check the voltages at P802. Use the screw head imeadiately above P802 as the ground point for the meter.

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Am I supposed to be measuring DC or AC Voltage at that point? If I place my meter on setting 'DC 2 V' (labeled in photo as 1) the reading goes all over the place plus and minus a few millivolts. If I place it on setting 'AC 200 V' (labeled as 2) it registers at most a .5 for a split second then zeroes for most of the pins. If I release the ground (black) it tends to stay at .5 but not sure that's a valid reading.

Am I doing it right? What does this mean?

[ratdude747]

Re: HP w2007 PTB-1773 - Where to start?

dc. ac is used for wall outlets and such

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

Am I supposed to be measuring DC or AC Voltage at that point? If I place my meter on setting 'DC 2 V' (labeled in photo as 1) the reading goes all over the place plus and minus a few millivolts. If I place it on setting 'AC 200 V' (labeled as 2) it registers at most a .5 for a split second then zeroes for most of the pins. If I release the ground (black) it tends to stay at .5 but not sure that's a valid reading.

Am I doing it right? What does this mean?

No, you aren't doing this right. Bear with me, teaching is not my strong suit.

Set the meter on 20Vdc. The main output voltage should be 5 Vdc, also it is possible ther is a 12Vdc output.

Also, do you have a picture of the entire meter (preferably without the leads plugged in). I think you have the leads plugged into the wrong holes.

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Here's my DMM. The position of the leads have worked well for capictance and diode testing thus far but I can understand if they're not right for this test.

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Also, here's my power board's output. Looks like it should be 5.1v.

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

The black lead should plug into the center socket (common) and the red lead into the left socket. There is a low resistance shunt from the right socket to the center. Again, set the meter to the 20 VDC range. Probe from Gnd to 5.1 VDC. You may be able to probe from the top of the connector.

If the voltage reads zero, set the meter to the 200 VDC range and check the voltage across the very large cap in the lower right corner of the board. It should read approximately 170 volts.

PlainBill

[Bobdee]

Re: HP w2007 PTB-1773 - Where to start?

The black lead should plug into the center socket (common) and the red lead into the left socket. There is a low resistance shunt from the right socket to the center. Again, set the meter to the 20 VDC range. Probe from Gnd to 5.1 VDC. You may be able to probe from the top of the connector.

If the voltage reads zero, set the meter to the 200 VDC range and check the voltage across the very large cap in the lower right corner of the board. It should read approximately 170 volts.

PlainBill

Good work spotting those wrong leads Plainbill,nice one
but i suspect that Maverick is on 240V supply, above might need amending (I suspect due to old postings)

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

Good work spotting those wrong leads Plainbill,nice one
but i suspect that Maverick is on 240V supply, above might need amending (I suspect due to old postings)

In which case he should set it on the 600 VDC range, right?

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

The black lead should plug into the center socket (common) and the red lead into the left socket. There is a low resistance shunt from the right socket to the center. Again, set the meter to the 20 VDC range. Probe from Gnd to 5.1 VDC. You may be able to probe from the top of the connector.

If the voltage reads zero, set the meter to the 200 VDC range and check the voltage across the very large cap in the lower right corner of the board. It should read approximately 170 volts.

PlainBill

Ok I probed the outputs of the power supply from the bottom of the board, and I get zeros. Probing the voltage across the largest cap reads 163 volts.

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

I never feel like probing the outputs of these boards reveals anything because what if there is feedback from the logic board that controls the power output? Without the logic board connected, it doesn't seem like it's a valid test. What has been your experience?

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

I never feel like probing the outputs of these boards reveals anything because what if there is feedback from the logic board that controls the power output? Without the logic board connected, it doesn't seem like it's a valid test. What has been your experience?

Every monitor I have worked on has had a similar power supply design. The supply is on whenever it receives AC power (A few have a switch that interrupts the AC power).

If you look at the connector you will see two lines that do feed back signals from the logic board. They are On/Off and BRI. They control the inverter. I'll let you figure out what the labels mean.

NOW, on to the interesting stuff. Assuming your house / shop voltage is 120 VAC, 163 volts across the large cap is about right.

I've attached edited versions of the pictures of the power supply. What are the numbers on the components I have circled? Also, what are the brand and series of the rest of the electrolytic caps on the board?

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

The circled caps are as follows:
82 uF 35v Su'scon 0729(M) UK 105 deg
2 x 1uF 50v Su'scon

The chip on the back of the board is hard to make out I think it's:
EA1530A
something10202
something7311

All other circular caps are Su'scon except for one black 22uF 50v CapXon directly above the circled caps.

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

I suspect one of the two 1 µf caps are bad. Actually, since they are Su'scon and CapXon, they are all suspect. I note that you saw some jitter the first time you tried to measure the voltage. I would double check that on the 2 V scale. If you de see signs of the voltage fluctuating it is virtually that the SMPS controller is good. In that case, replace every electrolytic capacitor in the power supply except the big one. If you are in the US I strongly recommend purchasing them from Digi-Key. Caps and shipping should run about $10.00

By the way, the control IC is a TEA1530AT.

PlainBill

[Krankshaft]

Re: HP w2007 PTB-1773 - Where to start?

Check Q105 and Q103 on the underside of the board as well they are the driver transistors for the inverter transformer.

Q103 looks especially bad with visible darkening around it.

Diode check function from gate to source reverse probes should only get reading in one direction. Do the same for gate to drain. The manufacturer was nice enough to silkscreen the lead designations for you.

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Are Q103 and Q105 the exact same part? I can make out most of Q105, but Q103 is all but burned off. If they are the same, they should probe/act the same, right? Because they don't.

When I probe Q105 (9962GH 722366) from G to S it approaches 1 fast. Reversing I get 0.8 ohms. G to D in both directions reads, but approaches 1 fast as well.

When I probe Q103 (suspected bad) from G to S it stays at 0.74 ohms in both directions. G to D reads a very slow increase from about 0.9 to 1.009 and a solid reading of 1.003 in the other direction.

Which one is acting correctly? BTW I left the probing leads in the same place on my DMM, just switched to Diode check.

[Krankshaft]

Re: HP w2007 PTB-1773 - Where to start?

It should only read a value in one direction if it reads in two the transistor is shorted.

If the text looks melted off you can bet the transistor is shorted.

Inverter transformer driver transistors seem to be like HOTs they are heavily stressed and fail often.

Yes both transistors are the same.

[Krankshaft]

Re: HP w2007 PTB-1773 - Where to start?

It looks like the two transistors are connected together the only way to get a true reading would be to remove one.

If you replace one be sure to replace them both.

Also be sure to check for cracked solder joints all over the board it may just be the pics R811 for example looks cracked to me.

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

If you look at the connector you will see two lines that do feed back signals from the logic board. They are On/Off and BRI. They control the inverter. I'll let you figure out what the labels mean.

PlainBill

PlainBill, I'll take a stab in the dark: does BRI stand for BRIghtness?

I took another power board (just to learn) that I knew was working, and sure enough, you can see the voltages even though it's not connected to the logic board. It makes sense now--how can the logic board give the feedback if it's not being constantly powered?