Hannspree HF289H With Unstable Picture

[zzazz]

Hey all,

I have a Hannspree HF289H monitor that started acting strangely a few days ago.

Regardless of the screen resolution, refresh rate or input used (hdmi, VGA), every 1-3 minutes the image will roll vertically for a few seconds. It reminds me of an old VHS tape.

I have also seen the upper corner of the screen turn white and spread outward, then just as suddenly the color will revert to normal.

The logic board and power supply looked fine, no bulged capacitors. What could be causing these issues?

Any help is appreciated, Thanks.

[retiredcaps]

Re: Hannspree HF289H With Unstable Picture

Post clear focused top down pictures of all your boards following my sig file below exactly. We want the picture compositions like so

https://www.badcaps.net/forum/showpo...94&postcount=1

[zzazz]

Re: Hannspree HF289H With Unstable Picture

Here are the pictures, thanks.

[jetadm123]

Re: Hannspree HF289H With Unstable Picture

On your third photo of the logic board, with the power supply connected to the logic board, try measuring the DC voltage output of the voltage regulators. They appear to be U103, U101, U102 and U901? (to the right of U102). Use a mounting screw as your ground and measure the legs and tab of each regulator. Report your readings along with the part number of each regulator.

[retiredcaps]

Re: Hannspree HF289H With Unstable Picture

OReport your readings along with the part number of each regulator.

Like jetadm123 says, report them like so along with the part number (include all lines on the IC) of the IC. For example,

U100
AS1117-33
pin 1 = 0.0
pin 2 = 3.3
pin 3 = 5.0

[zzazz]

Re: Hannspree HF289H With Unstable Picture

Here are the voltage readings, part number in italics.

U101
80e
17-18L
pin 1 = 0
pin 2 = 1.8
pin 3 = 3.2

U102
1084
0809nL
pin 1 = 2.4
pin 2 = 3.6
pin 3 = 5.1

U103
1084-33
0813LL
pin 1 = 0
pin 2 = 3.2
pin 3 = 4.8

U904
8cL
1117L
pin 1 = 0
pin 2 = 0
pin 3 = 0

[jetadm123]

Re: Hannspree HF289H With Unstable Picture

You might want to measure U904 again as you seem to have no input voltage to the regulator.

[retiredcaps]

Re: Hannspree HF289H With Unstable Picture

You might want to measure U904 again as you seem to have no input voltage to the regulator.

Also, unless you have an analog multimeter, report all the numbers on the multimeter.

A regulator that measures 3.2 implies 3.20 which means it is bad (out of specification). However, if the real reading is 3.29, then report it as 3.29.

[tom66]

Re: Hannspree HF289H With Unstable Picture

This sounds a lot like a loose LVDS cable, especially the fade to white. Try reseating the cable going from the main board to the board at the top of the LCD.