Need Help! - HP VS19e - Recapped Already

[jc2468]

Hi,

Need some help on what to check next. Still experiencing 2 seconds to black.
Board has been recapped. Backlight comes on and then goes black, image is visible by shining flashlight into screen.

-CCFL tubes appear good, tested with known good ones, same issue. I can see each tube light up briefly. Even tried swapping out 2 at a time.
-Inverter transformers appears good, primary 0 ohms, secondary about 450 ohms (both transformers the same, tested out of circuit)
-diodes/transistors/mosfets appear good, no shorts

Can someone point me where to look next?

thnx!

[jetadm123]

Re: Need Help! - HP VS19e - Recapped Already

Welcome to the forum! Nice pics and a good job of testing so far. Did you try checking the 8-pin chips Q104 and Q105 (next to each inverter transformer) for shorts? They might be duo mosfets or transistors.

[retiredcaps]

Re: Need Help! - HP VS19e - Recapped Already

-CCFL tubes appear good, tested with known good ones, same issue. I can see each tube light up briefly. Even tried swapping out 2 at a time.

People seem to test ccfls different than what I expect so please clarify.

1) you used one good ccfl with 3 original HP VS19e ones. Did all the ccfl's stay on more than 2 seconds?
2) you then moved the good ccfl into each of the 4 possible connectors. Did any connector stay on more than 2 seconds?

edit: Excellent clear focused pics.

[PlainBill]

Re: Need Help! - HP VS19e - Recapped Already

I agree, good pictures. ALMOST good enough to identify I101, the inverter controller. What is that part number?

The good news is this is a through-hole design. That makes tracing the circuit easier. The bad news is this is a very minimalist design.

Also, if tracing circuitry becomes necessary, it will be necessary to have a picture of the back that includes ALL of the traces.

PlainBill

[jc2468]

Re: Need Help! - HP VS19e - Recapped Already

jetadmin123,

I did a quick check of Q104/Q105. They seem ok. Dual mosfets with a diode between 2 terminals.

retiredcaps,

Yes, I tested the CCFL the same way you asked. All the bulbs stayed for the same amount of time, regardless on which position the good bulb was at. I even tried every combination with 2 known good bulds.

PlainBill,

The I101 has the following on it

0Z9930DN
52017212G
0051A


Thnx
J

[mockingbird]

Re: Need Help! - HP VS19e - Recapped Already

There are three small caps on the board which I would like you to check... One on the top right, and two on the bottom middle. Did you replace these? If not, list the series. Also, I noticed you have some Panasonics there, most probably FC or FM. What was there before?

Can you take a picture of your logic board?

[jetadm123]

Re: Need Help! - HP VS19e - Recapped Already

Check the following voltages on I101 (OZ9930):

pin 1 (ENA) greater than .55V

pin 6 (VDD) approx 5V

pin 8 (ISEN) approx 1.25V

[jc2468]

Re: Need Help! - HP VS19e - Recapped Already

mockingbird,

those small caps were replaced as well already. I believe they tested ok, but I replaced them anyways. The other caps, can't remember the brand/series, most likely ones that are on the bad caps list. Some were showing signs of failure.

jetadm123,
pin 1 - approx 5V
pin 6 - approx 5V
pin 8 - when backlight on, about 75mV, backlight off was -25mV

[jetadm123]

Re: Need Help! - HP VS19e - Recapped Already

Try checking the resistance values of R111 and R130. Be aware that surrounding devices can affect your readings.

[mockingbird]

Re: Need Help! - HP VS19e - Recapped Already

mockingbird,
those small caps were replaced as well already. I believe they tested ok, but I replaced them anyways. The other caps, can't remember the brand/series, most likely ones that are on the bad caps list. Some were showing signs of failure.

Yea, but what was there before that you needed to replace? Did you match the ESR and ripple of the original series?

[jc2468]

Re: Need Help! - HP VS19e - Recapped Already

jetadm123,
they are both 496 and 498 ohms. no difference measured in-circuit or out of circuit
are they within spec? i have a hard time deciphering the bands on these resistor.
red-black-white-white-gold if i'm not mistaken.

mockingbird,
i can't remember, but i think i did look at the series before replacing.
not sure about those smaller 3 caps mention, i might of just replaced it with whatever low esr panny i had on hand. I was actually under the assumption that any bloated high esr cap with be better off being replaced by any low esr type?

[jetadm123]

Re: Need Help! - HP VS19e - Recapped Already

The resisitor values should be 499 ohms 1% tolerance, so you're right on. Can you check the voltage on pin 7 of I101? And to verify you said in your first post, you checked all the the diodes and transistors for shorts?

[jc2468]

Re: Need Help! - HP VS19e - Recapped Already

jetadm123,
Pin 7 on I101 measures +1.,54V when the monitor is off and +1.42V when it is on.
yes, I did check all the transistors/diodes...no shorts, unless I missed something.
I even removed Q106/Q107 and checked, they appear fine.

[jetadm123]

Re: Need Help! - HP VS19e - Recapped Already

Need to verify that when you did the recap you used a 22uf for C102 and 2.2uf for C103.

Since you can see an image with a flashlight, is it possible to bring up the menu and try lowering the brightness to say 50%? Just wondering if lowering the current to the tubes might allow the OZ9930 to operate properly.

[alexanna]

Re: Need Help! - HP VS19e - Recapped Already

Check the following voltages on I101 (OZ9930):

pin 1 (ENA) greater than .55V

pin 6 (VDD) approx 5V

pin 8 (ISEN) approx 1.25V

Pin 1 was reported to be 5 volts,
First off a little disclaimer, I do not have a data sheet on the controller or schematic on this monitor.
On the monitors I have checked I have never noticed 5 volts on the enable pin at the inverter controller.
I wonder if there would be any benefit of checking the enable voltage at the connector of the logic board to the PS/inverter board to see if is indeed 5 volts. I usually see just above 3 volts at the enable pin at the connector, and a much lower voltage at the controller.

[jetadm123]

Re: Need Help! - HP VS19e - Recapped Already

Pin 1 was reported to be 5 volts,
First off a little disclaimer, I do not have a data sheet on the controller or schematic on this monitor.
On the monitors I have checked I have never noticed 5 volts on the enable pin at the inverter controller.
I wonder if there would be any benefit of checking the enable voltage at the connector of the logic board to the PS/inverter board to see if is indeed 5 volts. I usually see just above 3 volts at the enable pin at the connector, and a much lower voltage at the controller.

Good info. I've searched high and low for the controller datasheet and have come up with nothing. Therefore, it's very difficult to figure out what's the voltage should be. It would be interesting to see what the pin 1 voltage is if jc2468 were to push the power button off.