Hanns G HG216D flashing power button

[Sparks88]

i have the above monitor and after downloading about 20 schematics (various viewsonic) i still havnt found an exact match to the power board, 24 and 5 volt lines are present but the monitor just flashes the power led, there is a ticking noise which seems to be coming from the video card, if i disconnect the power cable from the video board then the monitor powers up with a white screen, i intend to recap the power board as soon as i can get to a supplier which is open after the xmas break, i replaced 2 caps in the power supply a 22uf 50v one and a 10uf 50v one because the originals looked burned and on the positive leg of the i am getting a very high dc voltage (150v) any help would be appreciated.

[retiredcaps]

Re: Hanns G HG216D flashing power button

ion the positive leg of the i am getting a very high dc voltage (150v) any help would be appreciated.

1) You should be getting around 165V DC on cap C805 and only C805. 150 V DC implies that you are AC is around 106 V (150/1.414) which is pretty low.

2) There is one voltage regulator on the main board. It is I104.

a) What is the part number?
b) What is the DC voltage on each pin?

3) Some monitors require an input. Hookup a working computer with your favourite wallpaper.

a) Does the power LED still blink?
b) If yes, what color?

[Sparks88]

Re: Hanns G HG216D flashing power button

c805 measures 170v dc
I104 measures 4.69v on one leg, 3.3v on middle and tab, 0v on final, part number is 7585-3.3st

power led flashes rapidly blue
no difference with working pc connected

[retiredcaps]

Re: Hanns G HG216D flashing power button

The output voltage is correct for a 7585-3.3st.
So all your voltages on the power and main board look correct.

I108 may be your eeprom/flash. If it is corrupt, that might explain the power led flashing blue.

The only other idea I have right now is what is that 4 pin connector (upper right on the main board) going to?

[Sparks88]

Re: Hanns G HG216D flashing power button

the connector is for the built in speakers
is there any way to reset the eeprom (i have tried the up/down and power then connect to mains but that doesnt work or as a last resort reprogram it, i have a programmer so i would need the flash file but cannot find anywhere to download it.

[jetadm123]

Re: Hanns G HG216D flashing power button

Can you post a photo of the bottom of the power board? There may be some mosfets there that should be checked.

[Sparks88]

Re: Hanns G HG216D flashing power button

power section and inverter reverse side of board

[jetadm123]

Re: Hanns G HG216D flashing power button

What are the part numbers of the 4 8-pin devices in your 2nd photo?

[Sparks88]

Re: Hanns G HG216D flashing power button

the 2 outer ones are stm6920 the 2 inner ones are stm4953, I801 is ld7575ps

[jetadm123]

Re: Hanns G HG216D flashing power button

the 2 outer ones are stm6920 the 2 inner ones are stm4953, I801 is ld7575ps

The 6920 contains 2 n-channel mosfets and the 4953 contains 2 p-channel mosfets. Their datasheets can be found at alldatasheet.com

I suggest you try checking them for shorts. With your meter set to resistance, start with:

S1-G1
G1-D1
S1-D1

Do the same for:

S2-G2
G2-D2
S2-D2

Perform these tests for all 4 chips and post your readings.

[Sparks88]

Re: Hanns G HG216D flashing power button

all readings are consistently high and no shorts measured across any ic's

[jetadm123]

Re: Hanns G HG216D flashing power button

At this point, I don't see recapping the power/inverter board will do any good, since your getting voltage output for the inverter section and the signal/logic card.

The problem lies with the signal card. Since you think that there's a ticking sound comming from that card, it might possibly indicate a bad capacitor. Try listening for the sound using a cardboard tube from a roll of paper towels. As another test, use a hair dryer to heat up the caps on the signal card to see if that makes any difference.

[alexanna]

Re: Hanns G HG216D flashing power button

if i disconnect the power cable from the video board then the monitor powers up with a white screen,

In the first post you said with the power cable from the video board disconnected you get a white screen, is that the 30 pin ribbon that goes to the LCD panel?And With that cable disconnected is the PLED still flashing?

[Sparks88]

Re: Hanns G HG216D flashing power button

when i disconnect the power board from the logic board i get a white screen, i did not leave it too long as i was worried in case i might damage the inverter/lcd section.
Today i took a longer look and the ticking noise is actually coming from the mains input side of the power supply from the area of the optocoupler/main dc cap and if i disconnect the logic board the ticking changes to a very faint buzzing, disconnecting the lcd ribbon does not change anything from the original fault, i have looked over the logic board with a big illuminated magnifier but there isn't anything obvious, i have ordered a esr meter from portugal so when it arrives i will be able to test further as this is turning into a epic battle which i dont want to lose just on principle and i thank everybody for the help they are offering.

[PlainBill]

Re: Hanns G HG216D flashing power button

Hello!!!! The input voltage to I104 is very low - 4.69 volts. I would have expected it to be more in the order of 5.1 volts.

Using one of the mounting screws as ground, what is the voltage on each pin of the connector to the signal (AKA logic) board?

PlainBill

[retiredcaps]

Re: Hanns G HG216D flashing power button

Hello!!!! The input voltage to I104 is very low - 4.69 volts. I would have expected it to be more in the order of 5.1 volts.

Hmm, if that is the case, then it is my bad in post #4.

The datasheet at



suggests than Vin => 4V and Vout is 3.3 V (page 2) are typical.

Page 3 says minimum is 2.75V and maximum is 7V so I thought nothing of 4.69V being low.

[Sparks88]

Re: Hanns G HG216D flashing power button

hi Bill, the numbers on the power board and wire colours are inverted/opposite on the logic board so i am giving you the numbers off the logic board as follows

pin 1 no dc volts but 3.6v ac
pin 2 2.9v dc
pin 3 low voltage pulsing in time with front power led about .8v dc
pin 4 5v dc
pin 5 5v dc
pin 6 0v
pin 7 0v
pin 8 5v dc
pin 9 0v

[Sparks88]

Re: Hanns G HG216D flashing power button

i would like to add that pin 1 on the logic board does not have a connection on the power board, the wire goes across but the connector does not have any form of component or link on the power board

[PlainBill]

Re: Hanns G HG216D flashing power button

hi Bill, the numbers on the power board and wire colours are inverted/opposite on the logic board so i am giving you the numbers off the logic board as follows

pin 1 no dc volts but 3.6v ac
pin 2 2.9v dc
pin 3 low voltage pulsing in time with front power led about .8v dc
pin 4 5v dc
pin 5 5v dc
pin 6 0v
pin 7 0v
pin 8 5v dc
pin 9 0v

And I would say that pin 2 is probably the brightness adjust pin for the inverter, while pin 3 is the inverter On / Off control. I note that pins 4,5, and 8 al read 5Vdc, about what I would expect. There is a jumper in place of L803. I would suggest either measuring the voltage on that jumper or lifting one end of it and seeing if the power led stays on.

I would also be curious about the drop from the connector to I104.

PlainBill

[Sparks88]

Re: Hanns G HG216D flashing power button

jumper l803 measures aound the 26v mark, one thing i am not sure about is the positive leg of c810 measures 122v, this is wrong as the startup ic I801 has a max on vcc of 30v, the 27v zener Z803 has been changed and this doesnt make and difference, the fault probably lies in this area but all the components running that part of the circuit test ok, i will take another look at the 5v feed voltage drop on the logic board.