hmm. sometimes multimeter shows low battery indicator. measured one more time. same results. in 20 v range its out of range. will try to find another multimeter meanwhile.
Sorry to say, that cannot be, unless the Zener is open. As you can see in the circuit, that 15V Zener is for regulating the VCC for the SMPS IC to be at 15V max.
About 10VDC is correct voltage for NCP1200 SMPS IC to run. Check R615 Source resistor 0.22 Ohm for MOSFET Q601 to see if it is open. Check the DC voltage at the Drain pin of Q601 using C605 Negative leg as the ground ref point for this primary circuit section.
OK, just to sure, you are not getting any DC voltages on these caps?
hmm. maybe i am doing smth absolutely wrong or problem is behind the power board? pinout differs on actual board versus schema. measurements was taken without logic board and lcd panel connected.
OK, the power supply is not dead after all since you are getting the 5V, so next step will be hooking up logic board back but leave the flat cable from the logic board that go to the panel and see if those voltage readings change or disappear, especially the 5VDC. one thing does bug me is that you are getting only 13V for the inverter, but then the sch does not match your board 100%.
I will need you to post good closed up pictures of your board, both sides so I can trace out the connections and compare it to the sch.
Can you tell me what voltage are you getting at those 4 locations?
Notes: number 4 location are 3 pins, report reading at those 3 pin with the monitor connected to running PC. One of those 3 pin is for BL_ON (Backlights ON), another pin is for Backlights Dimming control, the 3rd pin I do not know what that one is for.
Can you tell me what voltage are you getting at those 4 locations?
Notes: number 4 location are 3 pins, report reading at those 3 pin with the monitor connected to running PC. One of those 3 pin is for BL_ON (Backlights ON), another pin is for Backlights Dimming control, the 3rd pin I do not know what that one is for.
if i understood you right.. than
V1 - 3.3V
V2 - 4.97V (pin to GND)
V3 - 5.07V (pin to GND)
V4 - from left to right - 3.13V, 0.02V, 0.02V (each pin to GND)
After all came to conclusion that my Power supply board IS OK.
Cut and repaired old sleeve from logic board to control buttons.
Connected all cables back. Now i am not able to see any diode indicator lights on control menu (diodes are OK). Pressing power on button seems doesn't work (silent dead monitor state).
May be someone can provide Logic board chema for this HP 1955 ?
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