HP F1905 19" dead. orange fast blinking power light.

[ntehicks]

I have an hp 19" F1905. when you plug the monitor in the power led blinks orange at a fast pace. I have done a search for this and Haven't been able to find info on the repair. Any help or direction would be very much appreciated.
I have examined all capacitors and also tested them with a cap tester. I have tested diodes on both boards.

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

Measure the voltage outputs from the power supply. It can also be caused by a corrupted user EEPROM (on the signal card).

PlainBill

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

Would I measure the voltage going to the Video processing board?

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

Would I measure the voltage going to the Video processing board?

Yes. Perhaps I should have been more explicit.

Don't measure the voltages going to the CCFLs, they can fry a DMM.

PlainBill

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

the 12 pin connecter that goes the the main video board I only am getting a 4.9 volt reading on pin 3 and 4 nothing on the rest of them.

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

I tested at T901 output is 18VCC at C914,C915,C922 I am getting 12.8v I think this is supose to be 13v

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

the 12 pin connecter that goes the the main video board I only am getting a 4.9 volt reading on pin 3 and 4 nothing on the rest of them.

Curious and curiouser. It appears there is only one secondary winding, and while it's difficult to be sure, it looks like IC905, Q904, and D901 are parts of a bucking regulator. L903 can be added to that, I think.

4.9 volts is reasonable for the output voltage to the signal card. I think the next order of business is pictures of that card.

PlainBill

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

here is the pictures of the Video card

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

here is the pictures of the Video card

First, I have marked two voltage regulators with their rated output voltages, please verify those voltages.

If the voltages are correct, the cause is likely to be a corrupted user eeprom. Google HP F1905 reset and see if any reset instructions can be found.

Next, I have marked U202 (left side of picture) with a yellow ?. What is the number on that IC?

I have marked 5 8 pin ICs with an orange ?. What are the numbers of those ICs?

PlainBill

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

I have checked both voltage regulators and they both test the correct voltage. I am having a hard time reading the numbers on the 4 Ic's
part U205 = M24C16-MN6T
part U203 = SST25VF010-20-4C-SA
part U101 = M24C02WMN6
part U102 = M24C02WMN6

I will search and see if I can find a reset procedure on this.

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

Part U202 = ALWH

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

I have checked both voltage regulators and they both test the correct voltage. I am having a hard time reading the numbers on the 4 Ic's
part U205 = M24C16-MN6T
part U203 = SST25VF010-20-4C-SA
part U101 = M24C02WMN6
part U102 = M24C02WMN6

I will search and see if I can find a reset procedure on this.

Well, let's see what you have there.

M24C16 = 16 Kbit serial EEPROM
SST25VF010 = 1 Mbit serial flash
M24C02 = 2 Kbit serial EEPROM

I'm going to say that U205 probably contains the user settings, U203 contains the firmware, and U101 and U102 contain ID information.

I'm hoping you find reset information for the monitor, because otherwise you are running out of options.

PlainBill

[jetadm123]

Re: HP F1905 19" dead. orange fast blinking power light.

Part U202 = ALWH

I did a little research and it would seem that ALWH is a factory marking for a EM6353 reset controller. It has a threshold of 2.93V and a 200ms reset timeout. Not sure if it failing will cause the power light to blink. It would be good to get PlainBill's opinion, since he's done the most research on reset controllers..

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

I did a little research and it would seem that ALWH is a factory marking for a EM6353 reset controller. It has a threshold of 2.93V and a 200ms reset timeout. Not sure if it failing will cause the power light to blink. It would be good to get PlainBill's opinion, since he's done the most research on reset controllers..

Thanks for doing the research for me. I'd briefly tried to verify that was a reset controller, but didn't find any leads.

ntehicks, it's a relatively easy test. Use one of the mounting screws as a ground point and measure the voltage on all three pins of U202. The pin by itself should be at 3.3 volts, the other two pins are Gnd and output. All three should be stable.

PlainBill

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

Thanks for doing the research for me. I'd briefly tried to verify that was a reset controller, but didn't find any leads.

ntehicks, it's a relatively easy test. Use one of the mounting screws as a ground point and measure the voltage on all three pins of U202. The pin by itself should be at 3.3 volts, the other two pins are Gnd and output. All three should be stable.

PlainBill

I tested the pin by itself and it has 5 volts. I tested the output and it is at 4.12 volts. does these mean that part is bad or it is getting to much voltage from something else that has failed.

[PlainBill]

Re: HP F1905 19" dead. orange fast blinking power light.

I tested the pin by itself and it has 5 volts. I tested the output and it is at 4.12 volts. does these mean that part is bad or it is getting to much voltage from something else that has failed.

That means the design was sub-optimal (i.e. crappy), but the reset controller is working properly.

Ordinarily you will tie the input of the reset controller to the power supply of the processor - which in this case is probably 3.3 volts; and you will use a controller whose threshold is slightly below the power supply voltage. Alternatively, you will tie the controller to the input voltage of the regulator supplying the processor, and choose a voltage above the minimum input voltage to the regulator.

This design is the worst of both possibilities. Still, that is NOT the reason the LED is flashing.

PlainBill

[ntehicks]

Re: HP F1905 19" dead. orange fast blinking power light.

do you know where I would find info on what it means for the power light to blink amber? I have looked at several service manuals for the 17" and 19" Hp monitors and they all talk about solid amber light nothing about blinking.